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Spontaneous Osteonecrosis/Subchondral Insufficiency Fractures of the Knee: High Rates of Conversion to Surgical Treatment and Arthroplasty
Abstract
Background:
Spontaneous osteonecrosis of the knee has recently been termed subchondral insufficiency fracture of the knee (SIFK) to appropriately recognize the etiology of mechanical overloading of the subchondral bone. The purpose of this study was to assess clinical outcomes of SIFK based on progression to surgical treatment and arthroplasty, and to evaluate the risk factors that increase the progression to arthroplasty.
Methods:
A retrospective review was performed on patients with a diagnosis of SIFK, as confirmed with use of magnetic resonance images (MRIs). Baseline and final radiographs were reviewed. Baseline MRIs were also reviewed for injury characteristics. Failure was defined as progression to surgical treatment or conversion to arthroplasty.
Results:
Two hundred twenty-three patients (71% female) with a mean age of 65.1 years were included. SIFK affected 154 femora (69%) and 123 tibiae (55%), with medial compartment involvement in 198 knees (89%); 74% of medial menisci had root or radial tears, with a mean extrusion of 3.6 mm. Varus malalignment was identified in 54 (69%) of 78 knees. Seventy-six (34%) of all patients progressed to surgical intervention at 2.7 years, and 66 (30%) underwent arthroplasty at 3.0 years. The rates of conversion to surgical intervention and arthroplasty increased to 47% (37 of 79; p = 0.04) and 37% (29 of 79; p = 0.09), respectively, in patients with >5 years of follow-up. The 10-year survival rate free of arthroplasty for patients with SIFK on the medial femoral condyle (p < 0.01), SIFK on the medial tibial plateau (p < 0.01), medial meniscal extrusion (p = 0.01), varus alignment (p = 0.02), and older age (per year older; p = 0.003) was significantly higher than the survival rates of those without each respective condition.
Conclusions:
Subchondral insufficiency fractures predominantly involve the medial compartment of the knee and commonly present with medial meniscal root and radial tears. Approximately one-third of patients progressed to total knee arthroplasty. Baseline arthritis, older age, location of the insufficiency fracture on both the medial femoral condyle and medial tibial plateau, meniscal extrusion, and varus malalignment were all associated with progression to arthroplasty.
Level of evidence:
Prognostic Level IV. See Instructions for Authors for a complete description of levels of evidence.
... Conservative treatment usually includes reduced weight bearing, optimized supplementation with vitamin D and calcium as well as antiresorptive therapy with denosumab or bisphosphonates [4,15,27,31]. Surgical procedures include subchondral core decompression, osteochondral grafting, autologous chondrocyte implantation or even total-/uni-compartmental knee replacement [6, 19,25,33,34]. ...
... In the case of an infracted subchondral bone plate, surgery is often recommended. Based on other factors such as anatomic location and lesions size, the most suitable surgical option is determined, such as core decompression, osteochondral grafting, autologous chondrocyte implantation or, in the case of severe ndings, partial or total knee arthroplasty [6, 19,25,29,33,34]. Furthermore, accurate veri cation of the bony lesion and therefore the subchondral bone plate is also important to evaluate possible progression. ...
... A comparison between CBCT and MDCT was not performed due to radiation safety concerns. However, it can be stated that CBCT has a more favourable cost-bene t pro le compared to MDCT due to a higher spatial resolution of CBCT with lower radiation dose exposure, providing excellent image quality for bone visualization [21,25,[32][33][34]. While routine MDCT scans and reconstructions of the knee in our department usually contain a slice thickness of 1-2 mm, the CBCT with a slice thickness of 0.2 mm clearly provides superior properties. ...
Purpose
To determine the diagnostic yield of cone beam computed tomography (CBCT) compared with 3T magnetic resonance imaging (MRI) for the evaluation of subchondral insufficiency fractures of the knee.
Methods
Consecutive patients with subchondral insufficiency fractures of the knee examined by 3T MRI and CBCT of the femoral condyles were reviewed. Two experienced raters graded the lesion severity on 3T MRI and CBCT images: grade 1: no signs of a subchondral bone lesion; grade 2: subchondral trabecular fracture or cystic changes, but without infraction of the subchondral bone plate; grade 3: collapse of the subchondral bone plate. Ratings were repeated after six weeks to determine reliability. In addition, the bone lesion size was measured as elliptical area (mm²) and compared between CBCT and T1-weighted MRI sequences.
Results
Among 30 patients included (43.3% women; mean age: 60.9 ± 12.8 years; body mass index (BMI) 29.0 ± 12.8 kg/m²), the medial femoral condyle was affected in 21/30 patients (70%). The grading of subchondral lesions between MRI and CBCT did not match in twelve cases (40%). Based on MRI images, an underestimation (i.e., undergrading) compared with CBCT was observed in nine cases (30%), whereas overgrading occurred in three cases (10%). Compared to CBCT, routine T1-weighted 3T sequences significantly overestimated osseus defect zones in sagittal (84.7 ± 68.9 mm² vs. 35.9 ± 38.2 mm², p < 0.01) and coronal orientation (53.1 ± 24.0 mm² vs. 22.0 ± 15.2 mm², p < 0.01). The reproducibility of the grading determined by intra- and inter-rater agreement was very high in MRI (intra-class correlation coefficient (ICC) 0.78 and 0.90, respectively) and CBCT (ICC 0.96 and 0.96, respectively).
Conclusion
In patients with subchondral insufficiency fractures of the knee, the use of CBCT revealed discrepancies in lesion grading compared with MRI. These findings are clinically relevant, as precise determination of subchondral bone plate integrity may influence the decision about conservative or surgical treatment. CBCT represents our imaging modality of choice for grading the lesion and assessing subchondral bone plate integrity. MRI remains the gold standard modality to detect especially early stages.
... Plain radiographs are typically used as initial imaging to investigate knee pain in middle-aged and older patients [3]. Therefore, MRI should be considered for older people presenting with sudden-onset non-traumatic knee pain and normal radiographs to ensure that other less common diagnoses do not fail [4][5][6]. ...
... The differential diagnosis of subchondral insufficiency fractures includes spontaneous osteonecrosis of the knee (SONK) which is due to circulatory impairment, leading to the ischemic death of the cellular components of the bone and marrow [2,6]. Nowadays, it is widely accepted that SONK may correspond to distinct evolutive phases of the same disease mechanism. ...
... Disease progression has been related to initial gravity and continued weight bearing. [9] Baseline arthritis, older age, location of the insufficiency fracture on both the medial femoral condyle and medial tibial plateau, meniscal extrusion, and varus malalignment have been associated with progression to arthroplasty [6,14,15]. ...
Subchondral insufficiency fracture of the knee (SIFK) is a non-traumatic condition that has been, historically, associated with the elderly. Early diagnosis and management are essential to prevent evolution to subchondral collapse and secondary osteonecrosis, developing prolonged pain and functional losses.
This article presents the case of an 83-year-old patient with severe right knee pain with 15 months of evolution, with sudden onset, and no history of trauma or sprain. Upon observation, the patient presented with a limping gait, antalgic posture with the knee in semi-flexion, pain on palpation of the joint medial line, severe pain on passive mobilization, limited joint range of motion, and a positive McMurray test. The X-ray only demonstrated a gonarthrosis grade 1 in the Kellgren and Lawrence classification with medial compartment affection. Due to the exuberant clinical picture with marked functional compromise, as well as clinical radiological dissociation, MRI was requested to rule out SIFK, which was later confirmed. The therapeutic orientation was then adjusted with an indication for non-weight bearing and analgesia, as well as orientation to an orthopedics consultation to request a surgical evaluation.
SIFK is difficult to diagnose and may have an unpredictable outcome due to delayed treatment approaches. This clinical case encourages clinicians to consider subchondral fracture in the differential diagnosis of knee pain when an older patient, with subnormal radiographic findings, reports severe knee pain in the absence of overt traumatic injury.
... Spontaneous osteonecrosis of the knee (SONK), also known as subchondral bone insufficiency fracture of the knee (SIFK), is described as a subchondral bone injury, with uncertain pathogenesis [1]. Primary vascular insult, mild trauma in an osteoarthritic joint, meniscal injuries and even osteoporosis are cited as possible related factors [1][2][3][4]. This disease affects more females over 60 years old [4]. ...
... SONK has its name under discussion because some authors suggest that necrosis is not the main involved factor. Due to its relationship with mechanical overload and focal stress on the subchondral bone resulting in small fractures, the suggestion is this would better be called subchondral bone insufficiency fracture [1,3,12]. ...
... Some risk factors are related to worse prognosis like meniscal extrusion, a SIFK affecting >40% of the involved site, advanced age, varus alignment and Kellgren & Lawrence radiographic classification > III [3,4,12]. In our reported cases, all patents presented large involvement of the MP (> 40%). ...
Spontaneous osteonecrosis or subchondral bone insufficiency fracture of the knee is a frequent injury in elderly female patients. The medial femoral condyle followed by the medial plateau is the most prevalent sites. When its evolution after conservative treatment is not favorable, medial unicompartimental arthroplasty is a surgical option with good results. We report three cases of early tibial component loosening of medial unicompartimental arthroplasty that could be related to a severe subchondral bone insufficiency fracture of the tibial plateau. In these cases of severe involvement of the tibial plateau, a more careful evaluation would be recommended to choose between unicompartimental and total knee replacement to avoid this early loosening.
... The MRI-based criteria used for the differential diagnosis of SONK were found to be heterogeneous. While some authors screened images for speci c features, such as focal hypointense areas on T1-or T2-weighted images, visible fracture lines or focal epiphyseal contour depressions [7,[13][14][15][16][17][18][19][20][21][22][23][24], others diagnosed SONK in the presence of bone marrow edema (BME) accompanying typical symptoms [25][26][27]. Two case reports radiologically demonstrated the primary overlay of fracture lines by BME [28,29]. ...
... In the included studies, the following parameters were found to negatively in uence the course of the disease: age over 65 years [24], varus alignment [17,19,24], affection of the medial femoral condyle or medial tibial plateau [24], meniscal extrusion [24], end stage osteoarthritis [24] and larger defect size [18,19]. Decreased bone mineral density [18,19] was associated with the onset of SONK, but not with its progression [17][18][19]. ...
... In the included studies, the following parameters were found to negatively in uence the course of the disease: age over 65 years [24], varus alignment [17,19,24], affection of the medial femoral condyle or medial tibial plateau [24], meniscal extrusion [24], end stage osteoarthritis [24] and larger defect size [18,19]. Decreased bone mineral density [18,19] was associated with the onset of SONK, but not with its progression [17][18][19]. ...
Background: Spontaneous osteonecrosis of the knee (SONK) is an insufficiently defined disease. Although recent research suggests that SONK may be caused by subchondral insufficiency fractures, its precise etiology remains unclear. Currently, no therapeutic guidelines exist.
Purpose: This systematic review aimed to collate the scientific literature on conservative treatment approaches for SONK and to derive respective recommendations.
Methods: The PUBMED database was searched for relevant articles published until November 2020. All articles in German or English language dealing with the conservative therapy of SONK were included. Animal research studies and reviews were not considered. Studies that used specific treatment outcomes as inclusion criterion and those that lacked a conservative treatment group, magnetic resonance imaging-based diagnosis, reported outcomes of conservatively managed patients or basic descriptions of the treatment modalities were excluded.
Results: Twenty-two articles comprising a total sample size of 521 patients were included. Eighteen of the included studies (82%) tested the effects of some form of restriction of weight-bearing, bisphosphonates or a combination of both. Sixteen studies (73%) reported clinical and/or radiological improvements. However, outcomes varied considerably in dependency of the radiologic presentation, demography and further prognostic factors.
Conclusion: Many conservative therapy methods appear effective in the treatment of orthopedic syndromes classified as SONK, with the most robust evidence existing for restriction of weight-bearing and bisphosphonates. The heterogeneity of radiologic presentations and treatment outcomes suggests that the generic term SONK might obscure the presence of different underlying pathologies. Indeed, many lesions may represent subchondral fractures, which should be referred to as subchondral fractures of the knee (SFK). A clear delineation of the disorders and standardized MRI-based diagnostic criteria are required.
... It has recently been suggested that the term "subchondral insufficiency fracture of the knee" (SIFK) should replace the historical "spontaneous necrosis of the knee" (SONK) nomenclature due to evidence that SONK usually does not manifest spontaneously nor present with necrotic bone on histologic entities (Hussain et al. 2017). Rather, SIFK has been described as sequela of mechanical overloading of the knee, which is often attributable to meniscal lesions and extrusion (Hussain et al. 2017;Pareek et al. 2020). Despite the revised nomenclature, the optimal management of these lesions at initial presentation remains challenging. ...
... Despite the revised nomenclature, the optimal management of these lesions at initial presentation remains challenging. Patients with SIFK have demonstrated high rates of pain, chondral thinning, and progression to arthroplasty (Pareek et al. 2020;Filardo et al. 2015;Meier et al. 2013;Pareek et al. 2019;Strauss et al. 2011). It is necessary for orthopedic surgeons to understand pharmacologic treatment options in order to improve outcomes and ideally prevent arthroplasty in this patient population. ...
Subchondral Insufficiency Fractures of the Knee (SIFK) can result in accelerated cartilage degeneration and poor outcomes. The presence of SIFK is difficult to manage and can cause persistent knee swelling, pain, and prolonged disability. Pharmacologic agents to suppress extensive bone remodeling, improve blood supply, and reduce pain have been suggested as treatment for these lesions. Nonoperative management with prostaglandins and bisphosphonates has emerged as a potentially efficacious intervention for symptom reduction and resolution of knee bone marrow edema. However, previous reports of potential serious adverse effects including atypical femoral fractures of the proximal femur raise concerns for clinical safety. This evidence-based opinion article demonstrates the potential clinical efficacy of various pharmacologic therapies, including prostaglandins and bisphosphonates, for the treatment of SIFK. The overall rate of reporting adverse effects in the literature is high (47.3%), while significant clinical improvements have been identified in 66% to 100% of the patient population. This collective information may help guide physicians during prescription drug therapy for the treatment of SIFK.
... Условно можно выделить начальную и развёрнутую стадии, стадию осложнений [4,5]. Также в данном случае очень подходящими классификациями являются модифицированная классификация Ficat для остеонекроза и рентгенологическая классификация Koshino [4][5][6][7]. На начальной (1-й) стадии перелома на МР-томограммах имеется только зона субхондрального отёка костного мозга, линии перелома ещё нет. Во второй стадии заболевания на фоне отёка костного мозга уже становится видимой субхондральная линия перелома, имеющая гипоинтенсивный на Т1-ВИ и Т2-FS-ВИ (PD-FS-ВИ) сигнал. ...
... Во второй стадии заболевания на фоне отёка костного мозга уже становится видимой субхондральная линия перелома, имеющая гипоинтенсивный на Т1-ВИ и Т2-FS-ВИ (PD-FS-ВИ) сигнал. Данная линия перелома может быть различной формы, но чаще встречаются два её варианта -линия почти параллельна поверхности мыщелка или линия имеет полулунную форму [7,8]. В третью стадию, помимо линии перелома, уже можно наблюдать склеротическую линию или фокальные гипоинтенсивные на Т1-ВИ и Т2-FS-ВИ (PD-FS-ВИ) участки склероза в зоне кортикального слоя кости. ...
Stress fractures are an actual problem of modern medicine. A fracture associated with insufficiency of the bone tissue of the knee condyles is a new type of stress fracture that occurs in people aged 50–55 years in response to a normal daily activity, but with damage to the weakened subchondral bone tissue of the joint caused by various reasons. This literature review is mainly based on data from foreign medical sources, since there is very little information on this type of fracture in Russian sources. This is primarily due to the fact that initially the world and Russian medical communities designated this type of fracture as a spontaneous osteonecrosis of the knee (SONK). In recent years, this term has been revised abroad and replaced by a more suitable one – subchondral insufficiency fracture of the knee (SIF/SIFK). According to modern concepts, it is necessary to clearly distinguish among the concepts of osteonecrosis and subchondral insufficiency fracture of the knee. The reason for this is not only differences in the pathogenesis of these pathologies, but also fundamentally different approaches to managing these patients. Thus, taking into account the fundamental differences in the treatment of patients with stress fracture associated with bone insufficiency and patients with osteonecrosis, and also the relevance of stress fracture of the knee condyles, we state the following aim – to study the available literature on this problem.
... Yamamoto and Bullough demonstrated the primary event of SONK was subchondral insufficiency fracture followed by secondary osteonecrosis between the fracture line and the subchondral bone plate, thus suggesting the shift of terminology into SIFK [3]. Historically, both SONK and SIFK have been used to describe the same disease, and the 2 terms were sometimes used interchangeably in the literature [8]. Some studies have challenged the term "spontaneous" in SONK does not reflect the actual pathophysiology and should be considered as a misnomer. ...
... The medial femoral condyle is affected in up to 94% of cases, while lateral femoral condyle involvement is much rarer. A review by Pareek et al. showed the lateral femoral condyle was involved in 7.2% of SIFK cases [8]. Some studies attributed the difference in blood supply between the medial and lateral femoral condyles. ...
Spontaneous insufficiency fracture of the knee is a potentially devastating yet poorly understood disease entity that can lead to secondary osteoarthritis. Most cases involve the medial femoral condyle, and the lateral femoral condyle is rarely affected. The optimal treatment for spontaneous insufficiency fracture of the lateral femoral condyle remains undetermined, and there are no previous dedicated reports on treatment outcome with unicompartmental knee arthroplasty. A middle-aged lady presented with subacute left knee pain and a locked knee. Subsequent imaging studies revealed a spontaneous insufficiency fracture of the lateral femoral condyle. In view of the isolated compartment involvement, unicompartmental knee arthroplasty was performed with satisfactory outcome. At 1 year postoperatively, the patient had complete resolution of knee pain and was able to resume working.
... In parallel, recent work shed light on spontaneous osteonecrosis of the knee (SONK) seen with MRTs. Originally thought to occur in idiopathic relation [45], evidence and terminology now accurately reflects the etiology as tear-associated extrusion and loss of biomechanic competence resulting in subchondral insufficiency fractures of the knee (SIFK) [13,46]. SIFK predominantly occurs with medial meniscus root and radial tears and has a known association with arthroscopic meniscectomy. ...
... Of these, 89% of SIFK involved the medial compartment and 75% had a BMI >35 [14•]. Unfortunately, this pathology is significant given the 30-50% rate of conversion to arthroplasty [13]. With the increase in machine learning utility in orthopedics, Pareek et al. created a model to predict progression to TKA following SIFK. ...
Purpose of Review
The role of the meniscus in preserving the biomechanical function of the knee joint has been clearly defined. The hypothesis that meniscus root integrity is a prerequisite for meniscus function is supported by the development of progressive knee osteoarthritis (OA) following meniscus root tears (MRTs) treated either non-operatively or with meniscectomy. Consequently, there has been a resurgence of interest in the diagnosis and treatment of MRTs. This review examines the contemporary literature surrounding the natural history, clinical presentation, evaluation, preferred surgical repair technique and outcomes.
Recent Findings
Surgeons must have a high index of suspicion in order to diagnose a MRT because of the nonspecific clinical presentation and difficult visualization on imaging. Compared with medial MRTs that commonly occur in middle age/older patients, lateral meniscus root injuries tend to occur in younger males with lower BMIs, less cartilage degeneration, and with concomitant ligament injury. Subchondral insufficiency fractures of the knee have been found to be associated with both MRTs and following arthroscopic procedures. Meniscus root repair has demonstrated good outcomes, and acute injuries with intact cartilage should be repaired. Cartilage degeneration, BMI, and malalignment are important considerations when choosing surgical candidates. Meniscus centralization has emerged as a viable adjunct strategy aimed at correcting meniscus extrusion.
Summary
Meniscus root repair results in a decreased rate of OA and arthroplasty and is economically advantageous when compared with nonoperative treatment and partial meniscectomy. The transtibial pull-through technique with the addition of centralization for the medial meniscus is associated with encouraging early results.
... Posterior root tears of the medial and lateral meniscus are known to have devastating consequences for the knee if left untreated [1,4,9,32]. Currently, the transtibial meniscal root repair is the surgical treatment of choice and with this technique the intraarticular contact pressures and tibiofemoral contact areas can be restored [8,10,23,30]. ...
... Meniscal root tears treated with non-operative treatments or other repair techniques were not evaluated 8:114 in this study and no control group was available. However, previous studies have shown less favorable results in patients with non-operative treatment or with partial meniscectomy [5,6,32]. Other limitations were the lack of baseline PROMs. ...
Purpose
To evaluate patient MRI results, demography and clinical outcome following transtibial repair of lateral and medial meniscal posterior root tears.
Methods
Patients treated with transtibial repairs of posterior meniscal root tears from 2015 through 2018 performed pre- and postoperative MRI scans. Outcome measures were continuity/discontinuity of the meniscal root and change in meniscal extrusion on MRI. Other outcomes were KOOS, Lysholm score, Tegner activity scale and the Global Rate of Change (GRoC) score for function and pain at follow-up.
Study design
Retrospective case-series.
Results
Of 41 patients, 36 attended follow-up at mean 26 (12–38) months postoperatively. At follow-up, 11 out of 18 lateral meniscus posterior root tear (LMPRT) versus 5 out of 18 medial meniscus posterior root tear (MMPRT) repairs were classified as healed. Meniscal extrusion decreased in LMPRTs from of 2.3 ± 1.5 mm to 1.4 ± 1.09 mm ( p = 0.080) and increased in MMPRTs from 3.1 ± 1.6 mm to 4.8 ± 1.9 mm ( p = 0.005) at FU (between-group difference, p < 0.001). LMPRT repairs were associated with ACL injury and additional meniscal injury and were younger and with lower BMI. No between-group differences were found for KOOS, Lysholm or GRoC Function scores. Tegner scale was higher and GRoC Pain score lower in the LMPRT group compared to the MMPRTs.
Conclusion
Following transtibial repair for meniscal posterior root repairs, the LMPRTs had a higher frequency of healing, whereas most MMPRTs continued to extrude, despite surgical intervention. The study confirmed that LMPRTs and MMPRTs differ in demography and associated injuries.
... 2,3,12 However, if MMPRT remains untreated, rapid degeneration occurs, resulting in medial compartmental OA or SIFK, which are consequences of insufficiency fractures combined with the necrosis of the surrounding bone. 13,14 The time from injury to surgery was longer (195 days) in this study than that reported in studies reporting MMPRT treatment using transtibial pullout repair (80e99 days); thus, relatively severe chondral damage was observed. 2,15,16 It is difficult to treat MMPRT using transtibial pullout repair if the cartilage is severely damaged because knee symptoms caused by chondral or subchondral lesions, such as knee pain at night or on weight-bearing, might not be relieved. ...
... 2,15,16 It is difficult to treat MMPRT using transtibial pullout repair if the cartilage is severely damaged because knee symptoms caused by chondral or subchondral lesions, such as knee pain at night or on weight-bearing, might not be relieved. 5,13,14,17 Therefore, UKA could be a beneficial option to treat isolated medial compartmental OA following untreated MMPRT that could not be treated using pullout repair. Furthermore, although UKA is generally performed for bone-on-bone medial OA due to its inferior outcome on patients without bone-on-bone arthritis, it could be a reliable option for the treatment of less radiographic OA after MMPRT. ...
Background
Cartilage degradation progresses rapidly following medial meniscus posterior root tear (MMPRT). Unicompartmental knee arthroplasty (UKA) has been performed for medial compartmental osteoarthritis following MMPRT. We evaluated the clinical and radiographic outcomes of UKA for medial compartmental osteoarthritis after an untreated MMPRT.
Methods
Twenty-one patients who underwent UKA for isolated medial compartment osteoarthritis following MMPRT were retrospectively investigated. Clinical outcomes were assessed using the Knee Injury and Osteoarthritis Outcome Score and knee range of motion. The posterior tibial slope and tibial component inclination were evaluated using plain radiographs.
Results
The mean follow-up periods were 25.5 ± 13.8 months. Clinical outcomes improved significantly postoperatively. The mean postoperative knee extension angle was −1.1° ± 2.1°, and the knee flexion angle was 134.3° ± 4.9°. The posterior tibial slope angle decreased from 9.0° ± 2.0° preoperatively to 5.4° ± 1.8° postoperatively, and postoperative tibial component inclination at the final follow-up was 2.9° ± 1.1° varus. No aseptic loosening or deep infections were observed.
Conclusion
UKA significantly improved clinical outcomes and could be a viable surgical option for treating isolated medial compartmental osteoarthritis accompanied by untreated MMPRT.
... At the medical center where this study was conducted, MRI was readily available and the mean time between symptom onset and first MRI was 2.2 months. However, in another study of 223 patients with SIFK and a mean follow-up time of 4.4 years, the rate of conversion to surgical treatment was 34% [13]. This may suggest that early diagnosis is important for nonoperative treatment to be successful. ...
... Although observational and case studies have suggested beneficial effects of bisphosphonates, a double-blind, placebocontrolled trial showed that ibandronate (a bisphosphonate) was not associated with a statistically significant or clinically meaningful improvement in functional status for patients with SIFK/SONK [15]. For those who progress to end-stage disease, knee arthroplasty is the treatment of choice [13]. Other surgical treatments include arthroscopic debridement, arthroscopic microfracture treatment, meniscal root repair, core decompression, and high tibial osteotomy. ...
... The presence of subchondral insufficiency fractures of the knee (SIFK), previously known as spontaneous osteonecrosis of the knee (SONK), [29,30] has been widely related to meniscal root tears with concomitant extrusion [30]. Several studies have found high rates of OA and the need for arthroplasty in patients with SIFK as a result of mechanical overload [30,31]. Other prior studies have suggested that the presence of bone marrow edema was directly associated with an increased risk of subchondral bone attrition [8]. ...
... 5. Протокол остеоденситометрии -Т-критерий минеральной плотности костной ткани шейки бедра на стороне поражения 1,9 (остеопения) Рис. 6. Протокол остеоденситометрии -Т-критерий минеральной плотности костной ткани тел позвонков L1-4 соответствует 3,0 (остеопороз) го сустава является МРТ. Именно МРТ позволяет успешно диагностировать Клинические наблюдения и краткие сообщения Clinical reviews and short reports данное заболевание на любой стадии его развития (в том числе на ранней стадии) [3,9,10]. Основными симптомами стресс-перелома от недостаточности являются субхондральная линия перелома, зона диффузного перифокального отека, участок субхондрального «гипоинтенсивного утолщения» в области перелома. ...
A clinical example is presented that demonstrates the capabilities of magnetic resonance imaging (MRI) in the diagnosis of a subchondral insufficiency fracture of the medial femoral condyle. An MR study protocol has been demonstrated that allows ensure successful diagnosis of this type of fracture.
... Medial meniscus extrusion and insufficiency fracture of subchondral bone are believed to be the prime factors that contribute to abnormal stress loading on the medial cartilage and the development of SIFK. 8,21,22 Ultimately, this can lead to subchondral collapse and secondary OA. Until now, it has been unclear whether the transcriptional profiling in the cartilage of SIFK differ from those of OA. ...
Purpose
Subchondral insufficiency fracture of the knee (SIFK) is a common cause of knee joint pain that mainly afflicts the elderly. Until now, how a sudden insufficiency fracture of subchondral bone affects the transcriptomic profiles of cartilage in SIFK and OA patients are largely unknown.
Methods
Single-cell RNA sequencing (scRNA-seq) was used to identify various cell subsets and evaluate transcriptomic differences in cartilage of SIFK and OA patients. In addition, the above findings were confirmed by histological evaluation and immunohistochemical (IHC) staining.
Results
We found that the transcriptomic profiles of cartilage in the SIFK patient was completely different from those of normal and OA patients. Accordingly, several novel cell clusters with activation of hypoxia and endochondral ossification signaling were identified in the SIFK cartilage. Chondrocyte trajectories analysis and IHC staining revealed that transcription factors including TCF4 were found to be highly up-regulated during the occurrence of SIFK, which might drive the reactive formation of cartilage and fibrous tissue and the activation of endochondral ossification.
Conclusion
This is the first report to elucidate the transcriptomic alterations and distinct cell type subpopulations in the cartilage of SIFK and OA by the use of scRNA-seq, which provides a new insight in the understanding of the initiation and progression of SIFK.
... 25,26 Given the significant potential for multisystem microvascular injury in COVID-19, it can be hypothesized that there is an increased risk of SONK related to COVID-19 -secondary to damage to blood vessels supplying the MFC regions, leading to impaired microcirculation blood flow and tissue perfusion, and ultimately causing ischemic necrosis of subchondral bone. 27,28 Such phenomenon may occur more often in patients with pre-existing, but clinically silent, excessive subchondral bone stress, with SARS-CoV-2 microvascular flow disturbances exacerbating the underlying knee pathology. ...
Background:
This article describes 2 cases of post-coronavirus disease 2019 (COVID-19) transient spontaneous osteonecrosis of the knee (PCT-SONK) observed in patients who had previously recovered from COVID-19 without corticosteroid administration.
Objectives:
The possible pathomechanisms by which a recent SARS-CoV-2 infection may contribute as a causative factor for osteonecrosis are reviewed, and the differential diagnosis and treatment are discussed.
Material and methods:
Two patients (males, 45- and 47-year-old) presented with sudden onset knee pain with no trauma history. The pain persisted during rest and at night. On magnetic resonance imaging (MRI), no subchondral bone thickening was observed; bone edema was diffusely distributed in the whole femoral condyle, in contrast to the more focal edema that is typically concentrated mainly around the subchondral region in classic SONK. Both patients were treated nonoperatively with no weight bearing and pharmacological agents, and complete resolution of symptoms was achieved.
Results:
A follow-up MRI 10 weeks after presentation revealed a near-complete loss of signal in the medial femoral condyle in both patients.
Conclusion:
Orthopedic surgeons should be cautious when sudden knee pain without concurrent trauma or a history of injury occurs shortly after severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, even with mild COVID-19 illness. While some studies report the development of post-COVID-19 osteonecrosis after lower doses of corticosteroids and sooner after their administration than in comparable non-COVID-19 cases, our study is the first to report 2 cases with no corticosteroid administration at all. Therefore, the authors believe it adds to the body of knowledge on the potential connections between COVID-19 and PCT-SONK. The transient nature of symptoms and radiological findings suggest that aggressive surgical treatment of non-injury local bone edema occurring shortly after SARS-CoV-2 infection should be avoided.
... Ранние диагностика и консервативная терапия обычно приводят к консолидации перелома без по следствий и позволяют избежать прогрессирова ния во вторичный остеонекроз и субхондральный коллапс [2,3,11]. Однако часто из-за негативных результатов первичной рентгенографии и отсут ствия назначения МРТ раннее лечение оказывает ся невозможным. ...
Subchondral stress insufficiency fracture of the knee is a new type of fracture that occurs in people of the older age group (from 50–55 years old) when exposed to a normal load on weakened bone trabeculae. In Russian sources, there is few information about this type of fracture. This is primarily due to the fact that initially the world and domestic medical communities designated this type of pathology as “spontaneous osteonecrosis of the knee”. In recent years, this term has been revised abroad and replaced by a more suitable one – “subchondral insufficiency fracture”. The etiology of insufficiency fracture is based on many diseases and conditions that lead to bone tissue weakening (osteoporosis, collagenosis, rheumatoid arthritis, post-radiation changes in bones, etc.). The main method for diagnosing this type of fracture is magnetic resonance imaging, since it is able to detect a fracture at any stage (especially at an early one). According to modern concepts, the terms “osteonecrosis” and “subchondral insufficiency fracture” require completely different approaches to the treatment. In the presence of complications, a fracture of insufficiency of the knee joint condyles threatens with subchondral collapse and secondary osteoarthritis, which leads to disability of a patient. Given the relevance of this medical problem, the aim of the review is to show the current state of literature data on the issue.
... Many studies have shown that patients who have had surgical repair of a tibial plateau fracture are at 1 1 1 1 increased risk of conversion to total knee arthroplasty (TKA) [1][2][3][4][5][6][7][8][9]. Often, these patients present with stiffness, pre-existing surgical incisions, orthopedic implants in place, cartilage damage, and possible malunion with or without bony defects [2,10]. ...
Objective
Total knee replacement after previous open reduction and internal fixation for tibial plateau fracture (conversion total knee) increases the complexity of the procedure and the complication rate. However, very little research exists to report on opioid use and cost associated with total knee arthroplasty (TKA) following tibial plateau fracture fixation as compared to primary TKA patients with no history of tibial plateau fracture. The aim of this study is to compare the differences in opioid use, reimbursements, and complication rates between patients with and without a history of tibial plateau fracture undergoing TKA.
Methods and materials
This is a retrospective large database review study. The study included patients across the country and in various clinical settings including, but not limited to, institutions, primary and tertiary care centers, and private practice. The PearlDiver database was reviewed for patients undergoing TKA between 2010 and 2019. Patients who underwent TKA following surgical repair of a tibial plateau fracture were identified using Common Procedural Terminology (CPT) codes and the appropriate International Classification of Diseases Ninth and Tenth Revision (ICD-9, ICD-10) codes. This group was then matched by age, gender, Charleston Comorbidity Index (CCI) score, Elixhauser Comorbidity Index (ECI) score, obesity, tobacco use, and diabetes to a group of similar patients who underwent TKA with no history of tibial plateau fracture. Opioid use over the episode of care, evaluated by morphine milligram equivalents (MME), and 30-day reimbursed cost were compared between groups using an unequal variance t-test. Complication rates at 30 days, 90 days, and one year postoperatively, and revision rates at one and two years postoperatively were compared using the odd’s ratio (OR) with 95% confidence intervals (95%CI).
Results
The episode of care cost for TKA was significantly lower for patients with a history of tibial plateau fracture ($11,615 ± $15,704) than it was for patients without a history of tibial plateau fracture ($16,088 ± $18,573) (p = 3.56E-14). At 30 days after knee arthroplasty, patients with a history of tibial plateau fracture had significantly more episodes of dehiscence (OR 2.665 [95% CI 1.327-5.351]; p = 0.006) and surgical site infection (SSI) (OR 1.698 [95% CI 1.058-2.724]; p = 0.028), which was significant at 90 days postop for both dehiscence (OR 1.358 [95% CI 0.723-2.551]; p = 0.001) and SSI (OR 1.634 [95% CI 1.100-1.802]; p = 0.015), as well as mechanical complications of the implant device (OR 2.420 [95% CI 1.154-5.076]; p = 0.019). There was no significant difference in the number of opioids prescribed postoperatively to patients with a history of tibial plateau fracture (2218 ± 3255 MME) compared to those without prior tibial plateau fracture (2400 ± 4843 MME) (p = 0.258). However, there was a small but statistically significant increase in the number of days postoperatively patients with a history of tibial plateau fracture were prescribed opioids (11.99 ± 7.73 days) compared to non-tibial plateau fracture patients (11.15 ± 7.18 days) (p = 0.004).
Conclusion
Patients with a history of tibial plateau fracture who then underwent conversion TKA have a lower reimbursed cost of TKA but a higher postoperative risk for dehiscence, mechanical complications, and surgical site infections. There is no significant difference in postoperative opioid use between the two groups.
... However, the extent of the lesion has no prognostic significance [29]. SIFK typically is observed along the central weight-bearing aspect of the femoral condyle (60-90%) and is commonly associated with medial meniscus tears [31][32][33]. It has been proposed that more than 50% of patients demonstrate radial or posterior root tears [34]. ...
Subchondral bone pathology (SBP) includes a wide range of pathologies, including trauma, post-cartilage surgery, osteoarthritis, transient bone marrow lesions (BML) syndromes, spontaneous insufficiency fractures, and osteonecrosis. They show common magnetic resonance imaging (MRI) findings termed bone marrow lesions (BMLs). However, the etiology and evolution of SBP in multiple conditions remains unclear. A key factor to address when studying a patient with BMLs is the distinction between reversible and irreversible lesions. MRI plays a significant role in the differential diagnosis based on recognizable typical patterns that have to be considered together with coexistent abnormalities, age, and clinical history. This chapter will focus on the current understanding of subchondral bone pathologies. Future research of BML will be mandatory to address the different pathologies better and determining appropriate treatment strategies.
... Several studies have described the outcome and natural history of spontaneous osteonecrosis of the knee. The outcome is affected by the size and width of the lesion, and small lesions heal under conservative treatment [24][25][26][27]. The healing mechanism of this disease is considered to result from reduced mechanical stress to the affected lesion without further collapse [19]. ...
Subchondral insufficiency fracture (SIF) of the medial femoral condyle has been proposed to be a primary event in so-called 'spontaneous osteonecrosis of the knee'. SIF is also known to be associated with bone marrow lesions (BML), but the detailed histopathology of the BML has not been fully clarified. We thus investigated the pathophysiology of BML based on MRI and histology in the 4 consecutive patients diagnosed with SIF, whose onset was within 4 months. In all cases, BMLs were enhanced on T1 Gd-enhanced MRI. Histologically, BMLs comprised serous exudate, fibrous tissue, and vascular-rich granulation tissue in the marrow space. In addition, a lower signal intensity line was observed within the BML in all cases on T1 MRI. Histologically, this line showed thickened bone trabeculae accompanied by fibrovascular tissue in two cases, while the other two cases showed formation of woven bone trabeculae around the original fractured bone trabeculae indicating the presence of another fracture in the bone marrow space. In summary, BML in SIF was considered to be a secondary phenomenon resulting from a subchondral fracture.
... Among the MRI-detected changes, the meniscus has attracted attention and its alterations are considered to be related to the pathophysiology of knee OA [13]. Indeed, medial meniscus extrusion (MME) and meniscus tearing are major risk factors for incidence and progression of knee OA [14][15][16][17][18][19][20][21][22]. However, the structural alterations associated with the gait speed of knee OA patients were not elucidated. ...
Objective
Knee osteoarthritis (OA) is one of the most common causes for reduction in gait speed. Research into the mechanism of underlying knee OA pain and other symptoms such as the reduction in the gait speed is essential to development of disease-modifying treatments for knee OA. We examined the magnetic resonance imaging (MRI)-detected structural alterations in knee joints those were associated with gait speed in knee OA patients.
Design
In this cross-sectional study, structural alterations in knee joints of 74 knee OA patients (51 females; mean 72.2 years old) were evaluated by MRI, and subjects’ gait speed was measured.
Results
The mean self-selected gait speed of the subjects was 0.73±0.21 m/s. A simple linear regression analysis revealed that MME was only correlated with the gait speed of the subjects with knee OA, while cartilage lesion, bone marrow lesion, subchondral bone cyst, subchondral cyst, osteophytes and meniscal pathology were not. A multiple regression analysis revealed that only MME was associated with gait speed (R²=0.484, p<0.001). The area under the receiver operating characteristic curve for determining <0.8 m/s of gait speed as evaluated by MME were 0.72 (95% confidence interval: 0.60-0.84). The relative risks at a cut-off <0.8 m/s for gait speed as evaluated by MME at 6.2 mm were 2.19 (1.28-3.46, p=0.01).
Conclusions
MME was associated with and the determinant for gait speed among MRI-detected structural alterations in patients with knee OA, suggesting the importance for elucidating the etiology of MME for developing a disease-modifying treatment for knee OA.
... Once substantial joint surface collapse has occurred, joint arthroplasty becomes to the most appropriate treatment option. [6,7] Although it is reported that unicompartmental knee arthroplasty is an excellent approach for patients with SONK, [8] there are some inevitable complications, such as infection, postoperative pain, prosthesis loosening. Thus, it is critical to develop a method for preventing further progression or delaying the onset of end-stage arthritis of the knee. ...
Background:
Bisphosphonates are commonly used to treat spontaneous osteonecrosis of the knee (SONK), while there are no relevant systematic review or meta-analysis designed to evaluate the effects of bisphosphonates on SONK.
Methods:
We will identify relevant randomized controlled trials from the PubMed, EMBASE, CINAHL and China National Knowledge Infrastructure, up to March 20, 2020. Data that meets the inclusion criteria will be extracted and analyzed using RevMan V.5.3 software. Two reviewers will assess quality of the included studies by using the Cochrane Collaboration risk of bias tool. Egger test and Begg test will be used to evaluate publication bias. And Grading of Recommendations Assessment, Development and Evaluation will be employed to assess the quality of evidence.
Results:
In this study, we will analyze the effect of bisphosphonates on pain intensity, physical function, biochemical including alkaline phosphatase, N-terminal propeptide of type I procollagen, and C-terminal type I collagen telopeptide, radiological outcome (evaluated by using Magnetic resonance imaging) and ratio of secondary surgery for patients with SONK.
Conclusion:
Our findings will provide evidence for the effectiveness and potential treatment prescriptions of bisphosphonates acupuncture for patients affected by SONK.
Purpose
To investigate the risk factors for varus progression after arthroscopic medial meniscal posterior root tear (MMPRT) repair and to compare the clinical outcomes between two groups: one with more varus progression and the other with less varus progression.
Methods
Patients who underwent isolated arthroscopic repair of MMPRT between 2015 and 2020 were enroled, and 2‐year follow‐up data were collected. Participants were categorized into two groups based on preoperative values of the weight‐bearing line (WBL) ratio: group A with <5.9% increase and group B with ≥5.9% increase. Various factors, including demographic features and radiological findings, were analysed and compared between the two groups. Intra‐meniscal signal intensity, meniscal healing, medial meniscal extrusion (MME), and articular cartilage grade were assessed preoperatively and 1‐year postoperatively using coronal magnetic resonance imaging.
Results
The final cohort consisted of 34 patients in group A and 46 in group B, with a mean age of 55.8 ± 11.2 and 59.8 ± 6.6 years, respectively. Preoperative WBL ratio and cartilage lesions in the medial compartment did not differ between the groups. Preoperative MME were significantly lower in group A than those in group B (2.6 ± 0.6 mm in group A and 3.5 ± 0.7 mm in group B, p < 0.05). Patient‐reported outcomes at the 2‐year follow‐up did not differ between the two groups (n. s.). In a logistic analysis, the odds ratio of MME was 2.1 ( p < 0.05), and the cutoff value of MME was 3.02 mm.
Conclusion
Preoperative MME is a risk factor for varus progression. However, no differences in patient‐reported outcomes were observed at 2‐year follow‐up, even in the group with greater varus progression.
Level of Evidence
Level IV.
These authors contributed equally to this work. Abstract: A medial meniscus posterior root tear (MMPRT) contributes to knee joint degeneration. Arthroscopic transtibial pullout repair (ATPR) may restore biomechanical integrity for load transmission. However, degeneration persists after ATPR in certain patients, particularly those with preoperative subchondral insufficiency fracture of the knee (SIFK). We explored the relationship between preoperative SIFK and osteoarthritis (OA) progression in retrospectively enrolled patients who were diagnosed as having an MMPRT and had received ATPR within a single institute. Based on their preoperative magnetic resonance imaging (MRI), these patients were then categorized into SIFK and non-SIFK groups. OA progression was evaluated by determining Kellgren-Lawrence (KL) grade changes and preoperative and postoperative median joint widths. SIFK characteristics were quantified using Image J (Version 1.52a). Both groups exhibited significant post-ATPR changes in medial knee joint widths. The SIFK group demonstrated significant KL grade changes (p < 0.0001). A larger SIFK size in the tibia and a greater lesion-to-tibia length ratio in the coronal view were positively correlated with more significant KL grade changes (p = 0.008 and 0.002, respectively). Thus, preoperative SIFK in patients with an MMPRT was associated with knee OA progression. Moreover, a positive correlation was observed between SIFK lesion characteristics and knee OA progression.
Subchondral insufficiency fracture of the knee (SIFK) causes acute knee pain in adults and often requires surgical management. Unicompartmental knee arthroplasty (UKA) and total knee arthroplasty (TKA) are the two most common surgical treatments for SIFK. While both UKA and TKA have their advantages, there is no consensus for SIFK localized on the medial compartment. We hypothesized that patients with SIFK treated with UKA would show superior patient-reported outcomes compared to those who underwent TKA. A total of 90 patients with SIFK located medially were included in the TKA (n = 45) and UKA (n = 45) groups. Size of SIFK lesions were measured on MR images. Patient reported outcomes in the form of the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), Hospital Special Surgery (HSS) scores, and Knee Society Scores (KSS) were assessed preoperatively, postoperative 6, 12 months, and at the final follow-up. There were no differences in the size of the SIFK lesion between two groups. At 6 months, WOMAC score was better in the UKA group than the TKA group (p < .01). Both groups had a significant improvement in WOMAC, HSS, and KSS scores at the final follow-up compared to preoperative scores. The UKA group had better range of motion of the knee preoperatively and postoperatively than the TKA group (p < .01 and p < .01). UKA group showed a higher relative risk than the TKA group in terms of complications (RR = 3.0) but with no statistical significance (P = 0.31). Unicompartmental arthroplasty and total joint arthroplasty can produce successful outcomes in patients with SIFK with proper patient selection, regardless of the size of SIFK lesion.
» Subchondral insufficiency fractures of the knee (SIFKs) are subchondral plate fractures with a prevalence of 2% to 4% of all knee injuries.
» Magnetic resonance imaging is the gold standard for evaluating SIFK, while plain radiographs have limited the use in the diagnosis of SIFK.
» Among patients with SIFK, 50% to 100% have meniscal pathology.
» Medical therapies and standard treatments traditionally used in the management of knee osteoarthritis differ from recommended management of SIFK patients.
» Randomized controlled trials and cohort studies with long-term follow-up are needed to determine the optimal rehabilitation protocol, interventional therapy, and prognosis of SIFK patients.
Background
Subchondral insufficiency fracture of the knee (SIFK) causes acute knee pain in adults and often requires surgical management. Unicompartmental knee arthroplasty (UKA) and total knee arthroplasty (TKA) are the two most common surgical treatments for SIFK. While both UKA and TKA have their advantages, there is no consensus for SIFK localized on the medial compartment. We hypothesized that patients with SIFK treated with UKA would show superior patient-reported outcomes compared to those who underwent TKA.
Methods
A total of 90 patients with SIFK were included in the TKA (n = 45) and UKA (n = 45) groups, respectively. SIFK lesions were measured on MR images. Hip knee ankle (HKA) angle was obtained preoperatively and at the final follow-up. Patient-reported outcomes in the form of the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), Hospital Special Surgery (HSS) scores, and Knee Society Scores (KSS) were assessed preoperatively, post-operative 6, 12 months, and at the final follow-up.
Results
The UKA group had better range of motion of the knee preoperatively and postoperatively than the TKA group (p<.01 and p<.01). At 6 months, WOMAC score was better in the UKA group than the TKA group (p<.01). Both groups had a significant improvement in WOMAC, HSS, and KSS scores at the final follow-up compared to preoperative scores. There were no surgical complications in the TKA group, but the UKA group had 3 revision cases due to a bearing failure.
Conclusion
Unicompartmental arthroplasty and total joint arthroplasty can produce successful outcomes in patients with SIFK with proper patient selection, regardless of the size of SIFK lesion.
Osteonecrosis has become the standardized term for a condition of many and varied etiologies. In this brief review, we note the evolution of the standardization of the condition and we also delve into the intraosseous versus extraosseous etiologies. Additionally, we list some of the more common medications known to cause osteonecrosis.
Spontaneous insufficiency fracture of the knee (SIFK) previously termed spontaneous osteonecrosis of the knee (SONK) is a painful knee condition that can occur spontaneously from unknown causes. Histology confirms that a subchondral insufficiency fracture is the true finding and osteonecrosis is a secondary and end-stage finding of the SIFK spectrum of disease. SIFK demonstrates a subchondral fracture and bone marrow edema (BME) on MRI and if left untreated, it can lead to collapse. SONK is most often diagnosed in middle-aged and older patients and is more common in females. It is usually found in the medial femoral condyle. Approximately one-third of patients progressed to total knee arthroplasty. Factors that contributed to disease progression included baseline arthritis, older age, location of the insufficiency fracture, meniscal extrusion, and varus malalignment. Positive outcomes have been reported when SIFK is treated with a combination of mosaicplasty (MOS) and high tibial osteotomy (HTO). And just as like MOS and HTO work better together, we need to collaborate to find solutions. We too are better together.
Introduction:
Subchondral insufficiency fractures of the knee (SIFK) can result in high rates of osteoarthritis and arthroplasty. The Implantable Shock Absorber (ISA) implant is a titanium and polycarbonate urethane device which reduces load on the medial compartment of the knee by acting as an extra-articular load absorber while preserving the joint. The purpose of this study was to evaluate whether partially unloading the knee with the ISA altered the likelihood of progression to arthroplasty utilizing validated predictive risk model (SIFK score).
Methods:
A retrospective case-control (2:1) study was performed on patients with SIFK without any previous surgery and those implanted with the ISA with outcome being progression to arthroplasty compared to non-operative treatment at 2 years. Baseline and final radiographs, as well as MRIs, were reviewed for evaluation of meniscus or ligament injuries, insufficiency fractures and subchondral edema. Patients from a prospective study were matched using the exact SIFK Score, a validated predictive score for progression to arthroplasty in patients with SIFK, to those with the ISA implant. Kaplan-Meier analysis was conducted to assess survival.
Results:
Total of 57 patients (38 controls:19 ISA) with mean age of 60.6 years were included. The SIFK score was matched exactly between cases and controls. The 2-year survival rate of 100% for the ISA group was significantly higher than corresponding rate of 61% for the control group (p<0.01). In ISA, 0% of the patients converted to arthroplasty at 2 years, and 5% (1 patient) had hardware removal at 1 year. When stratified by risk, the ISA group did not have a significantly higher survival compared to low-risk (p=0.3) or medium-risk (p=0.2) controls, though it had a significantly higher survival for high-risk groups at 2-years (100% vs 15%, p<0.01).
Conclusion:
SIFK of the medial knee can lead to significant functional limitation and high rates of conversion to arthroplasty. Implants such as the Implantable Shock Absorber have the potential to alter progression to arthroplasty in these patients, especially those at high-risk.
The history of subchondral insufficiency fracture of knee is closely related to a pre-existing diagnosis of spontaneous osteonecrosis (SONK). Previously, it was believed that subchondral linear or lunate pathological changes on magnetic resonance imaging in elderly patients with osteoporosis are the result of spontaneous osteonecrosis that has occurred, but it was later found that a small proportion of patients with osteonecrosis of the femoral head initially have a failure fracture, then complicated by secondary osteonecrosis. The main methods for diagnosing subchondral insufficiency fracture are radiography and magnetic resonance imaging. Magnetic resonance imaging has demonstrated high information content in subchondral insufficiency fracture of knee.
Knee pain is among the most common complaints that an orthopedic surgeon may see in practice. It is often worked up with X-rays and MRI, leading to a myriad of potential diagnoses ranging from minimal edema patterns to various types of osteonecrosis. Similarities in certain causes can pose diagnostic challenges. The purpose of this review was to present the 3 types of osteonecrosis observed in the knee as well as additional causes to consider to help aid in the diagnosis and treatment..
Purpose
To determine the magnetic resonance imaging (MRI) findings after mosaicplasty (MOS) for knee subchondral insufficiency fracture (SIFK), and to analyze the relationship between MRI findings and clinical outcomes.
Methods
We retrospectively reviewed the cases of consecutive patients who underwent MOS for SIFK with/without high tibial osteotomy (HTO) between Jan 1998 and Dec 2015. The MRI findings at 12 months after the surgery were assessed by modified MOCART score to determine the degree of bone marrow edema (BME), plug union, and plug necrosis. The clinical outcomes were assessed by Lysholm score to clarify the minimal clinically important difference(MCID) and patient acceptable symptom state(PASS) analysis.
Results
Total of 58 patients (17 men and 41 women) were enrolled in this study. Among them, 30 knees were treated by MOS alone and 28 knees were treated by MOS with HTO. The MOCART score of MOS alone patients were significantly lower in BME score(P =0.0060), and plug union score(P =0.0216), and in plug necrosis score(P =0.0326) than MOS with HTO patients. BME lesion was less likely to persist among elderly (odds ratio (OR) =1.20, P =0.0248) and female (OR =41.8, P =0.0118) patients. The MCID of Lysholm score were6.6 in MOS alone and 8.4 in MOS with HTO cases, but there were no significant association between MRI findings and the postoperative Lysholm score.
Conclusion
The MOS with HTO cases had better MOCART scores with less BME, better plug union, and less plug necrosis compared to MOS alone cases. Females and older patients had better resolution of BME, but there is no significant correlation between MRI findings and the postoperative Lysholm score. All cases in both groups showed improvement of Lysholm score exceeding MCID, thus MOS may be effective as a joint preserving surgery for SIFK.
The history of subchondral insufficiency fracture of knee is closely related to a pre-existing diagnosis of spontaneous osteonecrosis (SONK). Previously, it was believed that subchondral linear or lunate pathological changes on magnetic resonance imaging in elderly patients with osteoporosis are the result of spontaneous osteonecrosis that has occurred, but it was later found that a small proportion of patients with osteonecrosis of the femoral head initially have a failure fracture, then complicated by secondary osteonecrosis. The main methods for diagnosing subchondral insufficiency fracture are radiography and magnetic resonance imaging. Magnetic resonance imaging has demonstrated high information content in subchondral insufficiency fracture of knee.
Bone Marrow Lesions (BMLs) are typical findings in magnetic resonance imaging (MRI) present in different pathologies, such as spontaneous insufficiency fractures, osteonecrosis, transient BML syndromes, osteoarthritis, and trauma. The etiology and evolution of BMLs in multiple conditions remain unclear. There is still no gold standard protocol for the treatment of symptomatic BMLs in the knee. The biologic augmentation by Osteo Core Plasty is a new treatment modality showing promising results reducing pain with the aim to stop the progression of the disease. The purpose of this prospective study is to report the clinical outcomes and safety of Osteo Core Plasty for the treatment of symptomatic BMLs in the knee. Fifteen patients with symptomatic BMLs of the knee treated with the Osteo Core Plasty technique were included and followed prospectively for a minimum of 12 months. Each patient was evaluated before the surgery and respectively at 6 and 12 months using the Tegner Score, Marx Score, the International Knee Documentation Committee (IKDC), the Knee Injury and Osteoarthritis Outcome Score (KOOS) divided in pain, activity daily living (ADL) and Quality of Life (QOL) subscale and the Visual Analogue Scale (VAS) for pain. All clinical scores except Tegner and Marx score showed an overall statistically significant improvement through the entire follow-up (p<0.05) and a significant improvement (p<0.05) between each follow-up period (T0 versus T1; T0 versus T2; T1 versus T2). No complications were reported. These preliminary results confirm that biological subchondral bone augmentation by Osteo Core Plasty technique is a safe and effective minimally invasive treatment option for symptomatic BMLs in the knee at 1-year follow-up. There is still a need for high-quality RCTs studies and systematic reviews in the future to enhance further treatment strategies in preventing or treating BMLs of the knee.
Introduction
Subchondral bone pathology includes a wide range of pathologies, such as osteoarthritis, spontaneous insufficiency fractures, osteonecrosis, transient bone marrow lesions syndromes, and trauma. They show typical magnetic resonance imaging (MRI) findings termed bone marrow lesions (BMLs). However, the etiology and evolution of BMLs in multiple conditions remains unclear. There is still no gold standard treatment protocol in treating BMLs in the knee, and a variety of treatment modalities have been tested in the hope that they might reduce pain and stop disease progression.
Objectives
To review the treatment options for BMLs of the knee.
Methods
A literature review was performed that included searches of PubMed, Cochrane, and Medline databases using the following keywords: Bone marrow lesions, subchondroplasty, bone marrow concentrate, platelet-rich plasma (PRP), subchondral bone augmentation.
Results
The use of novel biologic techniques to treat BMLs in the knee, such as PRP and Bone Marrow Cells, has yielded promising clinical outcomes.
Conclusions
Future research of BMLs will be mandatory to address the different pathologies better and determining appropriate treatment strategies. There is still a need for high-quality RCTs studies and systematic reviews in the future to enhance further treatment strategy in preventing or treating BMLs of the knee.
Background
Subchondral insufficiency fracture of the knee (SIFK) is characterized by a subchondral lesion that may lead to end-stage osteoarthritis (OA). In patients who have SIFK in a precollapse state with varus malalignment, a joint-preserving technique such as open wedge high tibial osteotomy (OWHTO) should be considered.
Purpose
To evaluate the efficacy of OWHTO in primary OA and SIFK-dominant OA by clinical and radiological evaluations including magnetic resonance imaging (MRI).
Study Design
Cohort study; Level of evidence 3.
Methods
A total of 33 SIFK-dominant OA knees and 66 with primary OA that underwent biplanar OWHTO between March 2014 and February 2016 were included after 1:2 propensity score matching. The MRI Osteoarthritis Knee Score was used to assess bone marrow lesions (BMLs) preoperatively and at follow-up. The weightbearing line ratio, the hip-knee-ankle angle, and the joint line convergence angle were measured. The clinical outcomes assessed were range of motion, the American Knee Society Score, and the Western Ontario and McMaster University (WOMAC) score.
Results
The mean follow-up period was 41.2 ± 12.6 months. The distribution of preoperative BML grade in the SIFK-dominant OA group was significantly higher in both the femur and tibia ( P < .001 and <.001, respectively) than that in the primary OA group. However, the difference was not significant postoperatively (femur, P = .425; tibia, P = .462). In both groups, postoperative BMLs showed significant improvement compared with preoperative BMLs (primary OA [femur, P < .001; tibia, P = .001] and SIFK-dominant OA [femur, P < .001; tibia, P < .001]). The WOMAC pain score was higher in the SIFK-dominant OA group preoperatively (primary OA, 7.0 ± 3.73; SIFK-dominant OA, 9.17 ± 2.6; P = .032) even though it was not different at the final follow-up (primary OA, 2.11 ± 1.7; SIFK-dominant OA, 1.79 ± 1.32; P = .179).
Conclusion
OWHTO is an effective procedure not only for primary OA but also for SIFK-dominant OA. OWHTO can improve BMLs, which represent the main pathological feature of SIFK. Therefore, in patients who have SIFK with varus malalignment, OWHTO can be an attractive treatment option for preserving the joint and enhancing subchondral bone healing.
Purpose
The purpose of this study was to evaluate both the potential etiologies and resultant outcomes of patients who develop subchondral insufficiency fractures of the knee (SIFK) following arthroscopy.
Materials/Methods: A retrospective review was performed of all patients with an MRI diagnosis of SIFK following arthroscopic meniscectomy and chondroplasty over a 12-year period.
Results
28 patients were included with a mean age of 61 years and mean follow-up of 5.7 years. SIFK had a predilection for the medial compartment (n=25, 89%), specifically the medial femoral condyle (n=21, 75%). 7 patients (25%) developed SIFK in both the femoral condyle and tibial plateau in the ipsilateral compartment. 15 patients (54%) went on to conversion to arthroplasty at a mean of 0.72 years. The survival-free of conversion to arthroplasty was 57%, 45%, and 40% at 1-, 2-, and 5-years, respectively. Furthermore, 63% of patients with a meniscus tear and SIFK in the same compartment went on to arthroplasty (p=0.04). There was an increased risk of conversion to arthroplasty if SIFK was present in both the femur and tibia in the same compartment (p=0.04). Higher K-L grade at the time of SIFK diagnosis increased the likelihood of eventual arthroplasty (p=0.03). The presence of SIFK in both the femur and tibia in the ipsilateral compartment, increased K-L grade, and meniscus tear or prior meniscectomy in the same compartment as SIFK were associated with increased risk of eventual arthroplasty.
Conclusion
Post-arthroscopic SIFK most commonly occurs in the medial compartment, particularly for those who underwent a prior meniscectomy. The presence of root and radial meniscus tears in these patients is notable (75%). Ultimately, there is a high rate of progression of arthrosis (33%) and eventual conversion to arthroplasty.
Objective:
Treatments for steroid-induced osteonecrosis of the knee remains challenging, and there has not been sufficient evidence to support joint preservation surgery. This study evaluated long-term outcomes of osteochondral autologous transplantation (OAT) for steroid-induced osteonecrosis of the knee.
Design:
This retrospective case series included patients who underwent OAT for steroid-induced osteonecrosis of the knee from 1998 to 2008. The survivorship and need for secondary surgery were evaluated, and the clinical outcome was evaluated with the International Knee Documentation Committee (IKDC) subjective score. Preoperative and final Kellgren-Lawrence (KL) grade of the femorotibial and patellofemoral joints were individually evaluated.
Results:
Fourteen knees of 10 patients whose mean age was 32.5 (95%CI 26.4-38.6) years were included and followed for 14.0 (12.4-15.7) years. The mean lesion size of 6.9 (5.3-8.5) cm2 was repaired using 4 median (minimum 2, maximum 5) osteochondral plugs. No revision surgeries were performed for transplanted osteochondral plugs. The IKDC subjective score improved from 32.9 (24.5-41.3) to 74.2 (61.9-88.5) (P < 0.001). Knee flexion was improved at the final follow-up, and Seiza sitting was finally possible in 9 knees in 7 patients. Although the osteoarthritic change did not progress in femorotibial joint, patellofemoral joint showed early osteoarthritic changes at the final follow-up (mean KL grade: 0.8 [0.5-1.1]).
Conclusions:
Prosthetic joint replacement was successfully avoided for at least the first decade by OAT in young patients with steroid-induced osteonecrosis of the knee. The progression of KL grade of the patellofemoral joint is of concern.
Authors’ Response:
We thank Dr Filbay for her letter and comments. We agree that the articles Dr Filbay brought to our attention provide useful additional evidence about potential outcomes of nonoperatively managed patients, but the data do not alter our conclusion that the available evidence suggests meniscus repair should be adopted as the preferred initial intervention for medial meniscus root tears.1,4,5
Our search terms for our systematic review were included in our ‘‘Methods.’’ As published, our search terms were (‘‘meniscal’’[All Fields]) AND (‘‘plant roots’’[MeSH Terms] OR (‘‘plant’’[All Fields] AND ‘‘roots’’[All Fields]) OR ‘‘plant roots’’[All Fields] OR ‘‘root’’[All Fields]) AND
(‘‘therapy’’[Subheading] OR ‘‘therapy’’[All Fields] OR ‘‘treatment’’[All Fields] OR ‘‘therapeutics’’[MeSH Terms] OR ‘‘therapeutics’’[All Fields]). Unfortunately, neither of these articles was identified because ‘‘meniscal’’ was not included in the MeSH terms. While including these studies would have been helpful, they were not identified for indexing reasons, as stated in our ‘‘Limitations’’ section. In addition, both of these studies do not provide sufficient clarity about our key effectiveness parameter, osteoarthritis (OA) progression. Neogi et al,5 in Table 5, provide information about the number of patients in different Kellgren-Lawrence (K-L) grades at baseline and final follow-up. This information suggests at least 9 patients (27.3%) progressed by one or more K-L grades and thus developed OA according to our criteria.But the way the information is presented does not support an unequivocal assessment of the actual proportion of patients who progressed by one or more K-L grades. It might well be higher than 27.3%. The second study, Lim et al,4 does not present data about OA progression according to the criteria used for our definition in the analysis. However, the reported 2 observed total knee replacement (TKR) cases suggest that at least these 2 patients developed OA before undergoing TKR. Even using these ‘‘best case’’ assumptions for the studies of Neogi et al and Lim et al, and pooling them with the Krych data would lead to a computed annual rate of OA development of 15.3%, more than twice as high as the rate for repair of 7.2%.3-5 Furthermore, the 2 TKR cases in the Lim et al study suggest a best case TKR rate of 6.7% at 36-month follow-up, with corresponding freedom from TKR of 93.3% at 3 years. This is exactly in line with our model-based projection of freedom-from-TKR for the nonoperative group shown in Figure 3B of our article, suggesting our TKR event projection is not in disagreement with the Lim et al study data.
Furthermore, we welcome the opportunity to provide further comment on the Krych et al3 (2017) data, as Dr Filbay’s comments suggest a misinterpretation of these data. In that study, 27% of patients developed 2 grades or more radiographic OA change. Progression of at least 1 or more K-L grade occurred in 79% of patients. This study showed 87% of patients met the failure criteria (defined as progression to a total knee arthroplasty [TKA] or a severely abnormal International Knee Documentation Committee [IKDC] score), including 16 arthroplasties and 29 severely abnormal IKDC scores.3 In addition, all 7 of the patients who did not meet failure criteria rated their knee as abnormal and had radiographic progression of arthritis. While higher baseline K-L grade (2 or more compared to \2) was the only factor associated with an increased rate of arthroplasty, females
had worse subjective knee outcome score by IKDC compared with males. Body mass index (BMI) was not found to be a factor, but the average patient was obese with a mean BMI of 33.4 (reflective of a North American cohort). Lastly, while subjective outcomes may lag radiographic changes, Krych et al2 also demonstrated progression of medial compartment chondral thinning within 1 year after patients
being diagnosed with a medial meniscus root tear.
When interpreting data from the Lim et al and Neogi et al studies, several limitations should be considered. Lim et al4 had only 30 patients compared with Krych et al3 with 52. Furthermore, their study had a shorter follow-up period of 36 months compared with Krych et al3 with a 62-month average follow-up. Importantly, Krych et al3 reported a 31% progression to TKA at an average of 30 months, but many of these occurred after 36 months. Neogi et al5 also had a limited number of patients and a shorter follow-up. In addition, this study excluded patients with varus malalignment, which is a known factor for worse outcomes and, therefore, may not be representative
of a typical meniscal root tear population.
We thank Dr Filbay again for her interest in our study, bringing to our attention these 2 studies and the importance that systematic reviews have on our practice.4,5 However, as we have outlined, our study conclusion that meniscus repair should be adopted as the preferred initial intervention for medial meniscus root tears to prevent knee OA does not change.
Scott C. Faucett, MD, MS
Washington, DC, USA
Benjamin P. Geisler, MD
Menlo Park, California, USA
Jorge Chahla, MD, PhD
Santa Monica, California, USA
Aaron J. Krych, MD
Rochester, Minnesota, USA
Robert F. LaPrade, MD, PhD
Vail, Colorado, USA
Jan B. Pietzsch, PhD
Menlo Park, California, USA
REFERENCES
1. Faucett SC, Geisler BP, Chahla J, et al. Meniscus root repair vs meniscectomy
or nonoperative management to prevent knee osteoarthritis
after medial meniscus root tears: clinical and economic effectiveness
[published online March 1, 2018]. Am J Sports Med. doi:10.1177/
0363546518755754.
2. Krych AJ, Johnson NR, Mohan R, et al. Arthritis progression on serial
MRIs following diagnosis of medial meniscal posterior horn root tear
[published online September 26, 2017]. J Knee Surg. doi:10.1055/s0037-1607038.
3. Krych AJ, Reardon PJ, Johnson NR, et al. Non-operative management
of medial meniscus posterior horn root tears is associated with worsening
arthritis and poor clinical outcome at 5-year follow-up. Knee
Surg Sports Traumatol Arthrosc. 2017;25(2):383-389.
4. Lim HC, Bae JH, Wang JH, Seok CW, Kim MK. Non-operative treatment
of degenerative posterior root tear of the medial meniscus.
Knee Surg Sports Traumatol Arthrosc. 2010;18(4):535-539.
5. Neogi DS, Kumar A, Rijal L, Yadav CS, Jaiman A, Nag HL. Role of nonoperative
treatment in managing degenerative tears of the medial
meniscus posterior root. J Orthop Traumatol. 2013;14(3):193-199.
Background:
The cause of spontaneous osteonecrosis of the knee (SONK) and postarthroscopic osteonecrosis of the knee is unknown, and the mechanisms involved have been poorly characterized. Hypothesis/Purpose: The purpose of this study was to perform a detailed systematic review of the literature to examine proposed etiological mechanisms for SONK in order to establish an improved understanding of the processes involved. We hypothesized that the etiology of SONK would be multifactorial.
Study design:
Systematic review.
Methods:
A systematic review of the literature was performed by searching PubMed, Medline, Cochrane Database of Systematic Reviews, and the Cochrane Central Register of Controlled Trials. Inclusion criteria were all original research articles presented in the English language that reported on the suspected etiology of SONK. Reviews, case reports with fewer than 3 patients, cost-effectiveness studies, technical reports, editorial articles, surveys, special topics, letters to the editor, personal correspondence, and studies that only proposed factors for the progression of SONK were excluded.
Results:
After a comprehensive review of 255 articles, 26 articles were included for final analysis. Twenty-one (80.7%) of 26 articles implicated the role of the meniscus in the development of SONK, in an association with either meniscal tears or its development after meniscectomy. The medial meniscus and posterior meniscal root tears were implicated more frequently. All 4 studies incorporating histological findings supported the insufficiency fracture hypothesis as a pathological basis of SONK.
Conclusion:
Physicians should be cognizant of the high prevalence of medial meniscus root tears in patients with SONK. Meniscectomy and meniscal tears, particularly of the medial meniscus posterior root, increase contact pressures and create an environment from which insufficiency fractures can emanate. We believe the term SONK is a misrepresentation of the etiology and pathogenesis of the condition and should be replaced with subchondral insufficiency fractures of the knee. Further elucidation of the etiology is required.
Objectives
Medial meniscus posterior root tears (MMPRTs) are recognized as a source of pain and dysfunction, but treatment options remain a clinical challenge. Currently, outcomes are unknown following partial meniscectomy for these lesions. To determine (1) the efficacy of partial meniscectomy to treat MMPRTs compared to a matched group of non-operatively treated MMPRTs, and (2) risk factors for worse clinical and radiographic outcome.
Methods
This retrospective comparative study was performed to include 27 patients with MMPRTs that were treated with arthroscopic partial meniscectomy (PMM) and a minimum 2-year follow-up. These patients were then matched by age, gender, and BMI to a group of 27 patients with MMPRTs treated non-operatively (control group). Demographic data, radiographic findings, final Tegner and IKDC scores were obtained and compared between the two groups. Risk factors for worse clinical and radiographic outcome in the PMM group alone, including age, sex, BMI, initial K-L grade, subchondral edema, and insufficiency fracture on MRI were determined.
Results
Overall, 54 patients were included in the study. 27 patients (10M: 17F) with a mean age of 55±9 and a mean BMI of 32.8±5.3 were treated with PMM and followed for a mean of 5.5±2 years (range 2.3-9.3 years). In the PMM group, final median Tegner score was 3, mean IKDC scores were 67.8±20, median KL grades on weight-bearing AP films demonstrated progressive arthritis (median grade 1 to 2, p=0.001) and more patients had grade II or higher arthritis at final follow-up than baseline (91.3% vs. 36% p<0.01. Overall, 14 of the 27 patients (52%) treated operatively progressed to total knee arthroplasty at a mean of 54.3 months. When comparing the PMM and control groups, there was no significant difference in final median Tegner scores, mean IKDC, median K-L grades, progression to arthroplasty, or overall failure rate. Following PMM, female patients had lower final IKDC scores (74.6±16.7 vs. 44.00±2.8, p=0.02) compared to males, as well as a higher rate of arthroplasty (70.6% vs, 20.0%, p=0.009). Higher BMI correlated with lower IKDC scores (r=-0.91, p=0.01) and meniscal extrusion was associated with higher rate of arthritis at final follow-up (100% vs. 57%, p=0.02).
Conclusion
Partial meniscectomy for a MMRT provides no benefit in halting arthritic progression. Patients who undergo arthroscopic debridement for MMPRTs still progress to significant arthritis, poor clinical outcomes and a high arthroplasty rate (52%) at over 5-year follow-up. Compared to a non-operative control group, there was no benefit in any subjective or objective outcome measures from the arthroscopic partial meniscectomy. Female patients, higher BMI, and presence of meniscus extrusion were associated with worse outcomes and a higher rate of subsequent knee arthroplasty.
Bone marrow lesions (BML) of the knee are a frequent MRI finding, present in many different pathologies including trauma, post-cartilage surgery, osteoarthritis, transient BML syndromes, spontaneous insufficiency fractures, and true osteonecrosis.
Osteonecrosis (ON) is in turn divided into spontaneous osteonecrosis (SONK), which is considered to be correlated to subchondral insufficiency fractures (SIFK), and avascular necrosis (AVN) which is mainly ascribable to ischaemic events.
Every condition has a MRI pattern, a different clinical presentation, and specific histological features which are important in the differential diagnosis.
The current evidence supports an overall correlation between BML and patient symptoms, although literature findings are variable, and very little is known about the natural history and the progression of these lesions.
A full understanding of BML will be mandatory in the future to better address the different pathologies and develop appropriately-targeted treatments.
Cite this article: Marcacci M, Andriolo L, Kon E, Shabshin N, Filardo G. Aetiology and pathogenesis of bone marrow lesions and osteonecrosis of the knee. EFORT Open Rev 2016;1:219-224. DOI: 10.1302/2058-5241.1.000044.
Background:
High tibial osteotomy (HTO) is a well-established and commonly utilized technique in medial knee osteoarthritis secondary to varus malalignment. Accurate measurement of the preoperative limb alignment, and the amount of correction required are essential when planning limb realignment surgery. The hip-knee-ankle angle (HKA) measured on a full length weightbearing (FLWB) X-ray in the standing position is considered the gold standard, since it allows for reliable and accurate measurement of the mechanical axis of the whole lower extremity. In general practice, alignment is often evaluated on standard anteroposterior weightbearing (APWB) X-rays, as the angle between the femur and tibial anatomic axis (TFa). It is, therefore, of value to establish if measuring the anatomical axis from limited APWB is an effective measure of knee alignment especially in patients undergoing osteotomy about the knee.
Methods:
Three independent observers measured preoperative and postoperative FTa with standard method (FTa1) and with circles method (FTa2) on APWB X-ray and the HKA on FLWB X-ray at three different time-points separated by a two-week period. Intra-observer and inter-observer reliabilities and the comparison and relationship between anatomical and mechanical alignment were calculated.
Results:
Intra- and interclass coefficients for all the three methods indicated excellent reliability, having all the values above 0.80. Using the mean of paired t-student test, the comparison of HKA versus TFa1 and TFa2 showed a statistically significant difference (p<.0001) both for the pre-operative and post-operative sets of values. The correlation between the HKA and FTal was found poor for the preoperative set (R=0.26) and fair for the postoperative one (R=0.53), while the new circles method showed a higher correlation in both the preoperative (R=0.71) and postoperative sets (R=0.79).
Conclusions:
Intra-observer reliability was high for HKA, FTal and FTa2 on APWB x-rays in the pre- and post-operative setting. Inter-rater reliability was higher for HKA and TFa2 compared to FTal. The femoro-tibial angle as measured on APWB with the traditional method (FTal) has a weak correlation with the HKA, and based on these findings, should not be used in everyday practice. The FTa2 showed better correlation with the HKA, although not excellent.
Level of evidence:
Level III, Retrospective study.
Meniscal root tears present in many forms and can have profound consequences on the health of knee articular cartilage. While the biomechanics, natural history, and treatment of root tears have been increasingly investigated, the spectrum of meniscal root tear patterns observed during arthroscopic examination has yet to be defined and categorized.
To establish a classification system for meniscal root tears by reporting the morphology of meniscal root tears from a consecutive series of arthroscopic surgeries. It was hypothesized that meniscal root tears could be grouped into types by distinct tear patterns and that recognition of tear pattern would affect treatment choice.
Case series; Level of evidence, 4.
All patients who underwent arthroscopic surgery from April 2010 to May 2014 by a single orthopaedic surgeon were included. After arthroscopic examination, data regarding the integrity of the meniscal roots were prospectively recorded in a data registry. Tear morphology and treatment received were subsequently extracted by 2 independent reviewers from operative notes and arthroscopic surgical photos.
A total of 71 meniscal root tears in 67 patients were grouped into tear types with similar tear morphologies. Meniscal root tear patterns were categorized into partial stable root tears (type 1; n = 5); complete radial tears within 9 mm of the bony root attachment (type 2; n = 48), further subclassified into types 2A, 2B, and 2C, located 0 to <3 mm, 3 to <6 mm, and 6 to 9 mm from the root attachment, respectively; bucket-handle tears with a complete root detachment (type 3; n = 4); complex oblique tears with complete root detachments extending into the root attachment (type 4; n = 7); and bony avulsion fractures of the root attachments (type 5; n = 7).
This study demonstrated that it was possible to establish a concise classification system to group patients with meniscal root tears by tear morphology. Treatments received varied across tear types.
© 2014 The Author(s).
The term insufficiency fracture implies inadequate bone and is applied to some subchondral knee magnetic resonance images. We reviewed bone mineral density, body mass index, meniscal extrusion, comorbidities, and demographics in 32 knee insufficiency fracture patients. Only five were osteoporotic. Meniscal extrusion was predominant.
Purpose
The literature supports systemic osteoporosis as a risk fracture for spontaneous osteonecrosis of the knee (SONK). SONK is also called a subchondral insufficiency fracture. Recognizing that insufficiency fracture and SONK are related, we designed this retrospective study to determine if knee subchondral insufficiency fractures were associated with osteoporosis based on bone mineral density.
Methods
Based on magnetic resonance imaging findings, 32 patients were diagnosed as having an insufficiency fracture by an orthopaedic surgeon with magnetic resonance imaging confirmation by a musculoskeletal radiologist. We reviewed body mass index, age, sex, comorbidities, demographics, and bone mineral density using both T-scores and Z-scores.
Results
The average age was 70, and only five patients were osteoporotic. Twenty-six of the 32 patients were female. The average age-related Z-score was 1 standard deviation above normal.
Conclusions
We conclude that osteoporosis is not the underlying cause of this disorder in the majority of patients.
Background and purpose Primary spontaneous osteonecrosis of the knee is a painful lesion in the elderly without any known cause. The onset of pain is usually acute. The prognosis is poor with high frequency of osteoarthritis, joint surface collapse, and subsequent knee surgery. In the present study, we determined whether bisphosphonates can prevent the joint surface collapse by delaying the post-necrotic remodeling.
Patients and methods Between 2006 and 2009, 17 consecutive patients (mean age 68 years) with clinical and radiographic signs of knee osteonecrosis were identified and given alendronate, 70 mg perorally, once a week for a minimum of 6 months. The patients were followed clinically, radiographically, and by MRI.
Results 10 of the 17 patients did not develop osteoarthritis (group A), 4 patients developed mild osteoarthritis but no knee joint surface collapse (group B), and 3 patients had a joint surface collapse (group C). 2 of the 3 patients in group C—as compared to none in the other groups—stopped medication prematurely, due to side effects.
Interpretation Compared to a previous, untreated series of osteonecrosis patients at our hospital, the clinical results in the present series appeared better. 59% of the patients had a complete radiographic recovery, as compared to 25% in the original study. 12% were failures regarding need to undergo surgery when bisphosphonates were given, as compared to 32% in the previous untreated series. An anticatabolic drug delaying the remodeling might be an effective treatment in osteonecrosis of the knee but further (preferably randomized) studies are necessary.
Meniscal root tears, less common than meniscal body tears and frequently unrecognized, are a subset of meniscal injuries that often result in significant knee joint disorders. The meniscus root attachment aids meniscal function by securing the meniscus in place and allowing for optimal shock-absorbing function in the knee. With root tears, meniscal extrusion often occurs, and the transmission of circumferential hoop stresses is impaired. This alters knee biomechanics and kinematics and significantly increases tibiofemoral contact pressure. In recent years, meniscal root tears, which by definition include direct avulsions off the tibial plateau or radial tears adjacent to the root itself, have attracted attention because of concerns that significant meniscal extrusion dramatically inhibits normal meniscal function, leading to a condition biomechanically similar to a total meniscectomy. Recent literature has highlighted the importance of early diagnosis and treatment; fortunately, these processes have been vastly improved by advances in magnetic resonance imaging and arthroscopy. This article presents a review of the clinically relevant anatomic, biomechanical, and functional descriptions of the meniscus root attachments, as well as current strategies for accurate diagnosis and treatment of common injuries to these meniscus root attachments.
The primary event preceding the onset of symptoms in spontaneous osteonecrosis in the medial femoral condyle (SONK) may be a subchondral insufficiency fracture, which may be associated with underlying low bone mineral density (BMD). However, the pathogenesis of SONK is considered to be multifactorial. Women over 60 years of age tend to have higher incidence of SONK and low BMD. We investigated whether there may be an association between low BMD and SONK in women who are more than 60 years old.
We compared the BMD of 26 women with SONK within 3 months after the onset of symptoms to that of 26 control women with medial knee osteoarthritis (OA). All the SONK patients had typical clinical presentations and met specified criteria on MRI. The BMDs measured at the lumbar spine, ipsilateral femoral neck, and knee condyles and the ratios of medial condyle BMD to lateral condyle BMD (medial-lateral ratios) in the femur and tibia were compared between the two groups. The medial-lateral ratios were used as parameters for comparisons of the BMDs at both condyles.
The mean femoral neck, lateral femoral condyle, and lateral tibial condyle BMDs were between x% and y% lower in the SONK patients than in the OA patients (p < 0.001). The mean femoral and tibial medial-lateral ratios were statistically significantly higher in the SONK patients than in the OA patients.
A proportion of women over 60 years of age have low BMD that progresses rapidly after menopause and can precipitate a microfracture. These findings support the subchondral insufficiency fracture theory for the onset of SONK based on low BMD.
Purpose:
Spontaneous osteonecrosis of the knee (SONK/Morbus Ahlback) mainly affects the medial condyle of elderly women. It is assumed that localized vascular insufficiency leads to necrosis of the subchondral bone with subsequent disruption of the nutrition supply to the cartilage above. The aetiology remains unclear in detail. Operative treatment procedures compete against non-operative strategies, whereas the outcome is unpredictable in many cases.
Method:
A consecutive case series of five patients suffering from SONK was analysed. All patients underwent a clinical examination, magnetic resonance imaging (MRI) and dual-energy X-ray absorptiometry scan, as well as laboratory analyses and visual analogue scale (VAS) evaluation. Our treatment regime is based on high-dose vitamin D administered orally and intravenous application of 3 mg ibandronate two times within 8 weeks. Another 8 weeks later, all patients were followed up including a follow-up MRI.
Results:
Within 4 weeks, all patients were free of symptoms. The MRI follow-up showed remission of the bone marrow oedema in every case studied. VAS decreased significantly from 7.4 ± 1.0 pre-interventional to 0.8 ± 1.0 post-interventional. No allergic reactions or other side effects were documented.
Conclusion:
We showed that our treatment regime not only eliminated the pathological findings in the MRI of all cases studied, but also decreased the pain level and functional limitations within a short-time period.
Level of evidence:
IV.
Researchers commonly use the femoral shaft-tibial shaft angle (FS-TS) from knee radiographs to estimate the hip-knee-ankle angle (HKA) in studies examining risk factors for knee osteoarthritis (OA) incidence and progression. The objective of this study was to determine the relationship between HKA and FS-TS, depending on the method of calculating FS-TS and the direction and degree of knee deformity.
120 full-length digital radiographs were assigned, with 30 in each of four alignment groups (0.0°-4.9°, and ≥5.0° of varus and valgus), from a large cohort of persons with and at risk of knee OA. HKA and five measures of FS-TS (using progressively shorter shaft lengths) were obtained using Horizons Analysis Software, Orthopaedic Alignment & Imaging Systems Inc. (OAISYS). The offsets between HKA and the different versions of FS-TS were calculated, with 95% confidence intervals (CIs). Pearson correlations were calculated.
In varus limbs use of a shorter shaft length increased the offset between HKA and FS-TS from 5.1° to 7.0°. The opposite occurred with valgus limbs (from 5.0° to 3.7°). Correlations between HKA and FS-TS for the whole sample of 120 individuals were excellent (r range 1.00-0.88). However, correlations for individual alignment groups were low to moderate, especially for the shortest-shaft FS-TS (r range 0.41-0.66).
The offsets obtained using the shorter FS-TS measurements vary depending on direction and degree of knee deformity, and therefore may not provide reliable predictions for HKA We recommend that full-length radiographs be used whenever an accurate estimation of HKA is required, although broad categories of alignment can be estimated with FS-TS.
Many different methods of evaluating disability after knee ligament injury exist. Most of them differ in design. Some are based on only patients' symptoms. Other include patients' symptoms, activity grading, performance in a test, and clinical findings. The rating in these evaluating systems can be either numerical, as in a score, or binary, with yes/no answers. Comparison between a symptom-related score and a score of more complex design showed that the symptom-related score gave a more differentiated picture of the disability. It was also shown that the binary rating system gave less detailed information than a score and that differences in a binary rating can depend on at what level the symptoms are regarded as "significant." A new activity grading scale, where work and sport activities were graded numerically, was constructed as complement to the functional score. When evaluating knee ligament injuries, stability testing, functional knee score, performance test, and activity grading are all important. However, the relative importance varies during the course of treatment, and therefore they should not all be included in one and the same score.
The natural history of spontaneous osteonecrosis of the medial tibial plateau remains controversial and incomplete. We have studied 21 patients (aged between 53 and 77 years) with clinical and scintigraphic features of spontaneous osteonecrosis of the medial tibial plateau who were observed prospectively for at least three years (37 months to 8.5 years). The mean duration of follow-up was 5.6 years.
The mean duration of symptoms at presentation was 4.7 weeks (3 days to 12 weeks). Radiographs of the affected knee at the first visit were normal in 15 patients and mildly arthritic in six. The characteristic radiographic lesion of osteonecrosis was noted at presentation in five of the mildly arthritic knees and during the evolution of the disease in eight of the radiographically normal knees. During the follow-up, subchondral sclerosis of the affected medial tibial plateau was noted in 16 knees.
There are three distinct patterns of outcome: 1) acute extensive collapse of the medial tibial plateau in two knees within three months of onset; 2) rapid progression to varying degrees of osteoarthritis in 12 knees, in eight within a year, in all within two years and deterioration of the pre-existing osteoarthritis in three; and 3) complete resolution in four knees, two of which were normal at presentation and two mildly osteoarthritic.
The two patients with acute extensive collapse and three who had rapid progression to severe osteoarthritis required total knee arthroplasty.
We conclude that osteonecrosis of the medial tibial plateau progresses in most cases to significant degenerative disease of the knee.
Background::
Arthroscopic meniscectomy has been commonly performed for persistent pain caused by degenerative medial meniscal posterior root tears (MMPRTs). However, risk factors that affect long-term outcomes and joint survivorship after meniscectomy are unclear.
Purpose::
To identify the risk factors associated with end-stage osteoarthritis after arthroscopic meniscectomy for degenerative MMPRT for middle-aged or elderly patients and to determine the joint survivorship according to the identified risk factors.
Study design::
Case-control study; Level of evidence, 3.
Methods::
Data from 288 patients (24 male and 264 female), followed for at least 5 years after arthroscopic meniscectomy for degenerative MMPRTs performed between 1999 and 2010, were examined retrospectively. The modified Lysholm score was used for clinical evaluation. Cox proportional hazards regression analysis was used to assess factors that affect joint survivorship when conversion to total knee arthroplasty (TKA) was taken as the endpoint; these factors were age, sex, body mass index (BMI), preoperative tibiofemoral alignment (varus [<2° valgus] vs well-aligned [2°-10° valgus]), preoperative Kellgren-Lawrence grade (0 or 1 vs 2 or 3), and the modified Outerbridge grade of the medial compartment. Kaplan-Meier survival analysis and the log-rank test were used to compare overall survivorship with respect to each significant risk factor.
Results::
Mean age at the time of surgery was 58.9 years (range, 43-78 years). Sixty (20.8%) patients underwent TKA at 7.0 ± 3.6 years (range, 1.1-14.4 years) postoperatively. The mean follow-up time for those who did not undergo TKA was 8.9 ± 2.9 years (range, 4.5-16.5 years). The overall modified Lysholm score improved from 64.4 to 81.3 ( P < .001), but progression of radiographic arthritis was noted in 156 (61.9%) patients ( P < .001) at 2 years postoperatively. Age (hazard ratio [HR] = 1.049), BMI (HR = 1.092), varus alignment (HR = 2.283), and Kellgren-Lawrence grade 2 or higher (HR = 2.960) were significant risk factors for end-stage arthritis requiring TKA. Well-aligned nonarthritic knees (n = 131, 45.5%) survived significantly longer before requiring TKA than did knees with varus alignment or radiographic arthritis ( P < .05). The 5- and 10-year survival rates in these low-risk groups were 97.7% (95% CI, 95.2%-100.2%) and 89.1% (95% CI, 82.4%-95.8%), respectively.
Conclusion::
Arthroscopic meniscectomy is an effective treatment for degenerative MMPRTs, with favorable long-term survival in well-aligned nonarthritic knees. However, meniscectomy should be undertaken cautiously in patients with varus alignment and preoperative radiographic osteoarthritis.
Purpose:
Spontaneous osteonecrosis of the knee affects the medial femoral condyle in patients above 55 years of age. Many reports and studies are available from western countries. But there is a gross paucity of literature on spontaneous osteonecrosis of the knee (SPONK) in the Indian subcontinent, either it is under-reported or detected at a later stage. The aim of our study was to detect SPONK in Indian population and describe its characteristics, treatment, and outcome.
Material and method:
A prospective study was conducted over a period of three years. All patients above 18 years with knee pain at rest and medial condyle tenderness without joint laxity were evaluated with plain radiographs and MRI. Further tests were done if radiological signs of osteonecrosis were present. Various parameters were recoded like Visual Analog Scale (VAS), Knee Society Score (KSS), and MRI Osteoarthritis Knee Score. Conservative treatment consisted of a combination of NSAIDs and bisphosphonates. Decompression with bone grafting was done if there was no improvement or deterioration at three month follow-up.
Results:
Ten patients were diagnosed with SPONK. The mean age was 50 years with male predominance (60%) with the involvement of medial femoral condyle (80%) or left knee (70%). Most cases were in Koshino stage 1. Mean VAS was 6.5 and mean KSS was 59. All clinical parameters showed improvement at one year.
Discussion:
A study with a bigger sample size and longer follow-up is needed to fill the lacunae of literature on this topic from the Indian subcontinent. In spite of the limitations, we did observe that in our population, males were more commonly affected than females, which is contrary to most studies on the subject. Also, the disease had an early age of onset (50 years) in Indian population as compared to Western and East Asian populations.
Conclusion:
Combined therapy of NSAIDs and bisphosphonates shows excellent results over a period of one year. Joint-preserving surgeries are effective even in Koshino stage 3 SPONK.
Objective:
Whether meniscal extrusion and bone marrow lesions (BMLs) are independently associated with the risk of knee osteoarthritis (OA) is unknown.
Methods:
Data was extracted from the Osteoarthritis Initiative (OAI) cohort. Participants were grouped according to the absence (Kellgren-Lawrence (KL) grade ≤ 1, n = 2120) or presence (KL ≥ 2, n = 2249) of ROA. Baseline meniscal extrusion and tibial BMLs were assessed. Tibial plateau cartilage volume was assessed at baseline and 72 months, while radiographic disease was assessed at baseline and 48 months. TKR was assessed at 72 months.
Results:
In those with ROA, the presence of a baseline meniscal extrusion (independent of BMLs) was associated with accelerated cartilage volume loss (medial tibia: -2.1%/annum vs -1.5%; lateral: -2.6%/annum vs -1.6%; both p < 0.001), progressive ROA and TKR (OR range 1.4 to 1.8; 95% CI range 1.1 to 2.9). The presence of a baseline BML (independent of meniscal extrusion) was associated with accelerated cartilage volume loss (medial tibia: -2.1%/annum vs -1.6%; lateral: -1.9%/annum vs -1.6%; p ≤ 0.02), progressive ROA and joint replacement (OR range 1.5 to 2.4; 95% CI range 1.1 to 3.4). In those with no ROA, a baseline medial meniscal extrusion was associated with accelerated cartilage volume loss (medial tibia: -2.1%/annum vs -1.2%, p < 0.001), and a baseline medial BML with incident ROA (OR 1.7, 95% CI 1.1 to 2.9).
Conclusions:
The presence of baseline meniscal extrusion and BMLs (independent of each other) are associated with incident and progressive knee OA and represent important structural targets for the treatment and prevention of knee OA.
PurposeMedial meniscus posterior root tears (MMPRTs) are recognized as a source of pain and dysfunction, but treatment options remain a challenge. The purpose of the study was to determine (1) the efficacy of partial meniscectomy to treat MMPRTs compared to a matched group of non-operatively treated MMPRTs, and (2) risk factors for worse clinical and radiographic outcome. Methods
This retrospective comparative study was performed to include patients with complete, isolated MMPRTs with documented clinical symptoms and were treated with arthroscopic partial meniscectomy (PMM) and a minimum 2-year follow-up. These patients were then matched by age, gender, and BMI to patients with the same diagnosis who were treated non-operatively. Clinical and radiographic outcomes were compared between the two groups. Analysis was performed to determine risk factors for worse clinical and radiographic outcome in the PMM group alone. ResultsOverall, 52 patients were included in the study. Twenty-six patients (9M:17F) with a mean age of 55 ± 9 and a mean BMI of 32.8 ± 5.3 were treated with PMM and followed for 5.5 ± 2.0 years (range 2.3–9.3 years). In the PMM group, final median Tegner score was 3, mean IKDC score was 67.8 ± 20, and more patients had grade II or higher arthritis at final follow-up than baseline (91.3 vs. 36%, p < 0.01). Overall, 14 of the 26 patients (54%) treated operatively progressed to total knee arthroplasty at a mean of 54.3 months. There was no significant difference in final Tegner scores, IKDC, K-L grades, progression to arthroplasty, or overall failure rate between the PMM group and non-operative group. Following PMM, female patients had lower final IKDC scores (44.0 ± 2.8 vs. 74.6 ± 16.7, p = 0.02) compared to males, as well as a higher rate of arthroplasty (70.6 vs. 20.0%, p = 0.009). Higher BMI correlated with lower IKDC scores (r = −0.91, p = 0.01) and meniscal extrusion was associated with higher rate of arthritis at final follow-up (p = 0.02). Conclusion
Partial meniscectomy for a complete MMPRT provides no benefit in halting arthritic progression. Patients who undergo PMM for MMPRTs still progress to significant arthritis, poor clinical outcomes and a high arthroplasty rate (54%) at over 5-year follow-up. Female gender, increased BMI, and meniscus extrusion were associated with worse outcome. Study designLevel III.
Background:
Medial meniscus posterior root tear (MMPRT) has been reported to play a key role in the development of spontaneous osteonecrosis of the knee (SONK) and osteoarthritis (OA) of the knee. However, little is known about the differences in the development of SONK and OA after MMPRT. The purpose of this study was to investigate the factors contributing to the development of these conditions.
Methods:
We evaluated the existence of MMPRT and the extent of medial meniscal extrusion in preoperative magnetic resonance images and proximal tibial morphology in radiographs of 45 patients with SONK and 104 patients with OA who underwent knee surgery.
Results:
There were no significant differences in age, gender, height, weight, and body mass index between the two groups. The incidence of MMPRT and the mean posterior tibial slope (PTS) were significantly higher in SONK than in OA patients (62.2% versus 34.3%, P=0.002, and 12.8° versus 10.5°, P<0.001, respectively). The mean extent of meniscal extrusion was larger in OA than in SONK patients (7.5mm versus 5.3mm, P<0.001). The mean tibial varus angle was 4.8° in SONK and 5.4° in OA, with no significant difference between the two (P=0.088). Multivariable logistic regression analysis showed that compared with OA, SONK was more closely associated with the existence of MMPRT and had a smaller extent of medial meniscus extrusion and higher PTS.
Conclusion:
MMRPT and higher PTS were more closely associated with the development of SONK than with that of OA.
Purpose:
Medial meniscus posterior root tears (MMPRTs) are a significant source of pain and dysfunction, but little is known about the natural history and outcome and for non-operative management of these lesions. The purpose of this study was to evaluate (1) the mid-term clinical and radiographic outcomes of non-operative treatment of MMPRTs and (2) risk factors for worse outcomes.
Methods:
A retrospective review was performed for patients with symptomatic, unrepaired MMPRTs and a minimum 2-year follow-up for IKDC and Tegner outcome scores. Baseline and final radiographs were reviewed and graded according to Kellgren-Lawrence scores. Baseline MRIs were reviewed for the presence of meniscal extrusion, subchondral oedema, and insufficiency fractures. Failure was defined as conversion to arthroplasty or severely abnormal patient subjective IKDC score.
Results:
Fifty-two patients (21M:31F) with a mean age of 58 ± 10 years were diagnosed with symptomatic MMPRTs clinically and confirmed by MRI and followed for a mean of 62 ± 30 months. Sixteen patients (31 %) underwent total knee arthroplasty at a mean of 30 ± 32 months after diagnosis with higher Kellgren-Lawrence grades associated with increased rates of arthroplasty (p = 0.01). Mean IKDC scores for the remaining patients were 61.2 ± 21 with significantly lower scores in females compared to males (75 ± 12 vs. 49 ± 20; p = 0.03). Mean Kellgren-Lawrence grades and rates of arthritis progressed over time on radiographs (1.5 ± 0.7 vs. 2.4 ± 1.0; p < 0.001 and 78 % vs. 51 %; p = 0.01). Overall, 87 % of patients failed non-operative treatment.
Conclusions:
Non-operative treatment of medial meniscus posterior horn root tears is associated with poor clinical outcome, worsening arthritis, and a relatively high rate of arthroplasty at 5-year follow-up. Female gender was associated with lower subjective scores and higher rate of arthroplasty. The current study provides a natural history benchmark for clinical outcomes that can be expected in patients with medial meniscus posterior horn root tears undergoing non-operative treatment and helps in counselling patients with these types of injuries.
Level of evidence:
IV.
Management guidelines for early-stage spontaneous osteonecrosis of the knee (SONK) have not been established. The purposes of this study were to review the outcome of conservative treatment for patients with early-stage SONK and to examine clinical factors affecting the prognosis.
Diagnosis of early-stage SONK was made based on the criteria consisting of specific clinical features including magnetic resonance imaging (MRI) findings. During the study period, all patients with this diagnosis underwent standardized conservative treatment. The study population comprised 38 knees in 36 patients with a mean age at presentation of 66.4years. The mean follow-up period was 34.9months. During the treatment course, progressive joint space narrowing or collapse of bony contours identified in serial follow-up radiographs was regarded as indicating a poor prognosis. The significance of potential prognostic factors such as age, gender, obesity, coronal alignment, lesion size, and MRI findings was analyzed using a multivariate logistic regression analysis.
The prognosis was defined to be poor in eight knees (21.1%). The multivariate logistic regression analysis for potential risk factors revealed that only varus alignment with a femorotibial angle (FTA) of 180° or more on the initial radiograph was significantly associated with the poor prognosis (P=0.01, odds ratio 28.1) while no other factors significantly correlated with the prognosis.
Approximately 80% of patients with early-stage SONK could be managed successfully with conservative treatment without progression of the disease process. The presence of varus deformity (FTA of 180° or more) was significantly associated with poor prognosis complicated with progressive deformity and prolonged disability.
Level IV, case series.
Copyright © 2015. Published by Elsevier B.V.
To determine the characteristics of femoral condyle insufficiency fracture (FCIF) lesions and their relative associations with the risk of clinical progression.
This HIPAA-compliant retrospective study was approved by our Institutional Review Board. Seventy-three patients (age range, 19-95) were included after excluding patients with post-traumatic fractures, bone marrow infarct, osteochondritis dissecans, or underlying tumor. Two board-certified musculoskeletal radiologists classified morphologic findings including lesion diameter, associated bone marrow edema pattern, and associated cartilage/meniscus damage. Electronic medical charts were evaluated for symptoms, risk factors, and longitudinal outcomes, including total knee arthroplasty (TKA). Imaging characteristics were correlated with clinical findings, and comparison of outcome groups was performed using a regression model adjusted for age.
The majority of patients with FCIF were women (64.4 %, 47/73), on average 10 years older than men (66.28 ± 15.86 years vs. 56.54 ± 10.39 years, p = 0.005). The most common location for FCIF was the central weight-bearing surface of the medial femoral condyle; overlying full thickness cartilage loss (75.7 %, 53/70) and ipsilateral meniscal injury (94.1 %, 64/68) were frequently associated. Clinical outcomes were variable, with 23.9 % (11/46) requiring TKA. Cartilage WORMS score, adjacent cartilage loss, and contralateral meniscal injury, in addition to decreased knee range of motion at presentation, were significantly associated with progression to TKA (p < 0.05).
FCIF are frequently associated with overlying cartilage loss and ipsilateral meniscal injury. The extent of cartilage loss and meniscal damage, in addition to loss of knee range of motion at the time of presentation, are significantly associated with clinical progression.
Purpose:
The incidence of root tears in patients with spontaneous osteonecrosis of the knee has been studied, but the incidence of spontaneous osteonecrosis of the knee in patients with medial meniscus root tears has not. We assessed the latter incidence and evaluated the characteristics of medial meniscus root tears by comparing clinical status, the degree of osteonecrosis, and meniscal extrusion in patients with horizontal tears.
Methods:
Sixty-three patients who were diagnosed with medial meniscus posterior horn tear and treated by arthroscopic surgery between March 2005 and March 2009 were evaluated retrospectively. Patients were divided into 2 groups, the root tear group (R group) and the horizontal tear group (H group). Functional scores and radiography, simple radiography, and magnetic resonance imaging were investigated.
Results:
No significant differences in age, body mass index, and symptom duration were observed between the 2 groups. The incidence of osteonecrosis was 12 of 36 knees (33.3%) in the R group and 4 of 27 (14.8%) in the H group. The mean absolute extrusion was 4.1 ± 0.7 mm and 3.5 ± 1.4 mm in the R and H groups, respectively (P = not significant). The mean relative percentage of extrusion in the R group (46.1% ± 9.0%) was greater than that in the H group (35.3% ± 13.2%) (P = .01). The degree of osteonecrosis (ellipsoidal volume) was also greater in the R group (423.1 ± 236.7 mm(3)) than that in the H group (175.8 ± 43.6 mm(3)) (P = .03). Though not significant, the visual analog pain score had a tendency to be more severe and knee scores had a tendency to be lower in the R group than in the H group.
Conclusions:
Medial meniscus root tears had a greater degree of meniscal extrusion and wider osteonecrosis than horizontal tears of the posterior horn related to loss of the main function of the meniscus.
Level of evidence:
Level III, retrospective comparative study.
A radiolucent lesion in the medial femoral condyle was observed in 40 knees in 39 patients over age 60. Most patients had had spontaneous onset of severe knee pain. Twelve knees were radiographically normal within 2 months following onset of pain. Seven knees proceeded to osteoarthritis whereas others became rather asymptomatic. Strontium-85 scintimetry of symptomatic knees showed exceedingly high values. Biopsy showed evidence of repair of bone tissue. The condition was identified as osteonecrosis, the natural history and management of which were discussed. Only 2 patients had a history of systemic adrenocorticosteroid treatment; no other conditions commonly associated with osteonecrosis were identified.
To discuss terminology, radiological differential diagnoses and significance of magnetic resonance imaging (MRI)-detected subchondral bone marrow lesions (BMLs) of the knee joint.
An overview of the published literature is presented. In addition, the radiological appearance and differential diagnosis of subchondral signal alterations of the knee joint are discussed based on expert consensus. A recommendation for terminology is provided and the relevance of these imaging findings for osteoarthritis (OA) research is emphasized.
A multitude of differential diagnoses of subchondral BMLs may present with a similar aspect and signal characteristics. For this reason it is crucial to clearly and specifically define the type of BML that is being assessed and to use terminology that is appropriate to the condition and the pathology. In light of the currently used terminology, supported by histology, it seems appropriate to apply the widely used term "bone marrow lesion" to the different entities of subchondral signal alterations and in addition to specifically and precisely define the analyzed type of BML. Water sensitive sequences such as fat suppressed T2-weighted, proton density-weighted, intermediate-weighted fast spin echo or short tau inversion recovery (STIR) sequences should be applied to assess non-cystic BMLs as only these sequences depict the lesions to their maximum extent. Assessment of subchondral non-cystic ill-defined BMLs on gradient echo-type sequences should be avoided as they will underestimate the size of the lesion. Differential diagnoses of OA related BMLs include traumatic bone contusions and fractures with or without disruption of the articular surface. Osteonecrosis and bone infarcts, inflammation, tumor, transient idiopathic bone marrow edema, red marrow and post-surgical alterations should also be considered.
Different entities of subchondral BMLs that are of relevance in the context of OA research may be distinguished by specific imaging findings, patient characteristics, symptoms, and history and are discussed in this review.
We describe injuries to the posterior root of the medial meniscus in patients with spontaneous osteonecrosis of the medial compartment of the knee. We identified 30 consecutive patients with spontaneous osteonecrosis of the medial femoral condyle. The radiographs and MR imaging were reviewed. We found tears of the posterior root of the medial meniscus in 24 patients (80%). Of these, 15 were complete and nine were partial. Complete tears were associated with > 3 mm of meniscal extrusion. Neither the presence of a root tear nor the volume of the osteonecrotic lesion were associated with age, body mass index (BMI), gender, side affected, or knee alignment. The grade of osteoarthritis was associated with BMI.
Although tears of the posterior root of the medial meniscus were frequently present in patients with spontaneous osteonecrosis of the knee, this does not prove cause and effect. Further study is warranted.
Several factors may play a role in the etiology of "spontaneous" osteonecrosis of the medial femoral condyle. Corticosteroids are known to induce osteonecrosis, and 45% of the patients in this study received steroids parenterally or by intra-articular injection. Another factor, heretofore given little attention, is the association of medial meniscal tears and "spontaneous" osteonecrosis. Twenty-one (78%) of 27 knees examined by arthrography demonstrated meniscal tears. Stress concentration over the edge of the meniscal fragment may result in ischemic necrosis of the femoral condyle. Early detection of a medial meniscal tear by arthrography in older patients and prompt treatment may be important in avoiding the late changes of "spontaneous" osteonecrosis.
A new total knee rating system has been developed by The Knee Society to provide an up-to-date more stringent evaluation form. The system is subdivided into a knee score that rates only the knee joint itself and a functional score that rates the patient's ability to walk and climb stairs. The dual rating system eliminates the problem of declining knee scores associated with patient infirmity.
A formula is derived for determining the number of observations necessary to test the equality of two survival distributions when concomitant information is incorporated. This formula should be useful in designing clinical trials with a heterogeneous patient population. Schoenfeld (1981, Biometrika 68, 316-319) derived the asymptotic power of a class of statistics used to test the equality of two survival distributions. That result is extended to the case where concomitant information is available for each individual and where the proportional-hazards model holds. The loss of efficiency caused by ignoring concomitant variables is also computed.
Aseptic osteonecrosis of the medial femoral condyle has recently been reported as a complication of arthroscopic surgery. The time interval between the onset of symptoms and pathognomonic MRI changes (diagnostic window) is not known for osteonecrosis of the knee. To determine the prevalence of early-stage spontaneous osteonecrosis of the knee (SONK) we prospectively examined 176 patients by MRI between May 1998 and December 1999. In six patients MRI revealed a bone marrow edema pattern and subtle subchondral bone changes in the medial condyle consistent with early-stage SONK (prevalence of 3.4%); in the 53 patients older than 65 years the prevalence was 9.4%. In 10 patients (5.7%) the bone and marrow changes on MRI imaging either resolved on follow-up MRI and were regarded as transient epiphyseal lesions or were considered to be reactive changes due to underlying degenerative articular disease. Including MRI in the preoperative diagnostic procedures could avoid missing the diagnosis of avascular necrosis before planning an operative treatment of suspected meniscal tears in elderly patients.
We report on a series of 5 patients over 60 years of age who had a symptomatic medial meniscus degenerative tear followed-up with magnetic resonance imaging (MRI) sequence without arthroscopic surgery who developed spontaneous osteonecrosis of the knee. The average patients age was 68 years. Clinically, all 5 patients had tenderness at the medial joint line. At initial evaluation, MRI studies showed degenerative tears of the posterior horn of the medial meniscus with no evidence of osteonecrosis. After a mean time of 2.7 months, all patients had increased pain and were re-evaluated with a second MRI study that showed images compatible with osteonecrosis. The size of the osteonecrotic image shown on the MRI was measured, and values obtained averaged 21% of the femoral condyle with a range from 17% to 26%. Development of osteonecrosis after arthroscopic partial meniscectomy has been previously reported as a rare and unexpected complication. We report an MRI sequence between medial meniscus degenerative tears and the development of spontaneous osteonecrosis without any arthroscopic procedure. Elderly patients with medial meniscal tears should be alerted of this potential sequence of events and the impossibility for the surgeon to predict or prevent this situation at this stage, especially before performing an arthroscopic meniscectomy.
Randomized, controlled trials, observational studies, and the hierarchy of research designs
- Concato