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Illustration of quadriceps angle (Q-angle) demonstrating a correlation between external tibial rotation and increasing Q-angle.
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Patellar stability is governed by unique anatomy and biomechanics, which greatly influence treatment strategies in the setting of instability. The patella is stabilized by the following 4 factors: lower extremity alignment, articular geometry, dynamic muscular stabilizers, and passive ligamentous stabilizers. Lower extremity malalignment results in...
Context in source publication
Context 1
... is measured in extension and is formed by the intersection of lines parallel to the quadriceps vector and patellar tendon. By convention, the quadriceps vector is measured from the anterior superior iliac spine to the center of the patella and the vector of the patellar tendon is measured from the center of the patella to the tibial tubercle (Fig. 2). Therefore, the Q-angle offers a rough estimate of the lateral force of the quadriceps on the patella. After dislocation, the Q-angle often decreases because of a new lateral resting position of the patella. One study confirmed that a small Qangle is associated with patients with chronic, recurrent dislocations. 10 The medial-lateral ...
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Background
Medial instability of the patellofemoral joint is a rare but known phenomenon that may result from an incompetent lateral patellofemoral ligament (LPFL). Surgical reconstruction of the LPFL has been described. However, anatomic details of the ligament have not been the subject of scrutiny.
Purpose
To describe the anatomic origin and ins...
Background
Recurrent patellar dislocation is common clinically, primarily in adolescents. However, the biomechanical properties of single- and double-bundle medial patellofemoral ligament (MPFL) reconstruction remain poorly understood. Methods
Six fresh frozen adult cadaveric knee specimens were obtained for this study. Each specimen was fixed at 0...
Introduction:
Trochlear dysplasia (TD) is a condition that is characterized by the presence of either a flat or convex trochlear, which impedes the stability of the patellofemoral joint (PFJ). The PFJ function is dependent on many different structures that surround the knee joint. The aim of this study was to analyse all the muscle components arou...
Background
A detailed understanding of the anatomy of the quadriceps tendon (QT) is clinically relevant, owing to its increased use as a graft in anterior cruciate ligament reconstruction.
Purpose
To qualitatively and quantitatively describe the anatomy of the QT in younger adult specimens.
Study Design
Descriptive laboratory study.
Methods
A to...
Objetivo
avaliar as condutas e os procedimentos feitos pelos cirurgiões de joelho do Brasil no tratamento das lesões do ligamento patelofemoral medial (LPFM) do joelho na luxação aguda traumática da patela.
Materiais e métodos
questionário de 15 questões fechadas que abordava tópicos relacionados ao tratamento das lesões do LPFM do joelho após lux...
Citations
... During the step-down task performed by university campus healthy women (age 18 years or older), a 3-D analysis of hip and knee kinematics revealed that the decreased ankle dorsiflexion ROM is linked to reduced knee flexion, greater hip adduction, and greater knee external rotation [50]. The observed faulty hip and knee kinematics (i.e., dynamic knee valgus) during functional activities have been linked with several overuse and overload injuries/disorders like ACL rupture [67], anterior knee pain [68], patellar instability/subluxation [69] and iliotibial band syndrome [70] in healthy young athletes and active individuals that can suggest that ankle dorsiflexion restriction may form a piece of the puzzle in these conditions' pathogenesis [50]. Furthermore, it was found that dynamic knee valgus (measured via high frontal knee projection angle) during a single-leg squat meant a 2.7 times higher possibility to be affected with acute lower limb injury and a 2.4 times higher chance of sustaining ankle injury within a year when compared with those with low frontal knee projection angles in basketball and floorball athletes (21 years old and under) [71]. ...
The objective of this literature review is to understand the role of ankle dorsiflexion range of motion in sports performance and the risk of injuries. The ankle harmonizes the interaction between the body and the supporting surface through adjusting to the supporting surface and handling forces to contribute effectually to different functional activities. Ankle dorsiflexion is an essential construct in many sport-specific skills. Ankle dorsiflexion is associated with activation of brain areas involved in movement preparation, sensory integration, motor planning/execution, balance, and visuomotor coordination. Ankle dorsiflexion was associated with enhanced activation of deep core and quadriceps muscles. Decreased ankle dorsiflexion is linked to compensations and altered kinetics and kinematics that can potentially affect sports performance and increase the chances of sustaining injuries. It is vindicated to consider more focus on ankle dorsiflexion range of motion in research studies, sports-related pre-season screening, clinical examination, injury rehabilitation, and return-to-sports judgment.
... 3 With patella alta, the patella articulates with the trochlear groove at greater flexion angle. 7,12,23 This anatomic difference increases risk of recurrent patellar instability with patella alta. The question of how this increased risk relates to chondral injury had not been answered. ...
Background
Patella alta is a risk factor for recurrent patellar instability. Differences in chondral injury in patients with patellar instability between patella alta and patella norma have not been evaluated.
Purpose
To analyze whether preoperative cartilage damage differs in severity and location between patellar instability patients with and without patella alta.
Study Design
Cohort study; Level of evidence, 3.
Methods
Patients with patellar instability who underwent patellar realignment surgery at a single institution with preoperative magnetic resonance imaging (MRI) scans were included. After measurement of Caton-Deschamps index (CDI) on MRI, patients were divided into patella alta (CDI ≥1.3) and patella norma groups. The area measurement and depth and underlying structures (AMADEUS) score was used to quantify cartilage defect severity on MRI.
Results
A total of 121 patients were divided into patella alta (n = 50) and patella norma (n = 71) groups. The groups did not differ significantly in sex ratio, age at MRI, body mass index, mean reported number of previous dislocations, or mean interval between first reported dislocation and date of MRI. A total of 34 (68%) of the patella alta group and 44 (62%) of the patella norma group had chondral defects ( P = .625) with no significant between-group differences in defect size ( P = .419). In both groups, chondral injuries most affected the medial patellar facet (55% in patella alta vs 52% in patella norma), followed by the lateral facet (25% vs 18%), and lateral femoral condyle (10% vs 14%). A smaller proportion of patients had full-thickness defects in the patella alta compared with the patella norma group (60% vs 82%; P = .030). The overall AMADEUS score was higher for the patella alta versus the patella norma group (68.9 vs 62.1; P = .023), indicating superior articular cartilage status.
Conclusion
Patients with patella alta had less severe cartilage injury after patellar instability, including a lower proportion with full-thickness defects and better overall cartilage grade. The location of injury when present was similar between alta and norma, with most defects affecting the medial facet, lateral facet, and lateral femoral condyle in descending frequency.
... As a consequence, joint laxity may be altered, resulting in patella dislocation due to an insufficient control of its movements (Carson et al., 1984). Similarly, muscle weakness affecting the quadriceps muscles (Greiwe et al., 2010), may facilitate the actions of the external forces acting to displace the patella, particularly weakness of the vastus medialis oblique that normally resists lateral patellar displacement. Additionally, foot deformities, observed in 74% of people with CMT (Laurá et al., 2018), may affect lower-limb biomechanics (Lufler et al., 2017), thereby altering the load distribution across the knee joint (Barton et al., 2010). ...
Background and purpose:
Patellofemoral (PF) dislocation is frequently encountered in clinical practice among people with Charcot-Marie-Tooth disease (CMT), but the frequency and risk factors for PF dislocation in adults with CMT are unknown. This study aimed to establish the incidence of PF dislocation in adults with CMT and to explore the risk factors associated with PF dislocation.
Methods:
This is a cross-sectional study involving adults with a diagnosis of CMT, attending their outpatient clinics at a specialist neuromuscular centre in the United Kingdom. Eighty-one individuals were interviewed about any PF dislocation and underwent a lower-limb assessment, with a focussed knee examination, to identify possible risk factors for PF dislocation. The incidence of PF dislocation was expressed as a percentage (number of individuals with a positive history of patellar dislocation/overall sample) and the association between different risk factors and PF dislocation was explored using logistic regression analysis.
Results:
The incidence of PF dislocation was 22.2% (18/81). PF dislocation was associated with a younger age at the time of the assessment (p = 0.038) and earlier disease onset (p = 0.025). All people bar two who dislocated had CMT1A (88.9%), but there was no difference in terms of CMT distribution with the non-dislocation group (p = 0.101). No association was found between PF dislocation and CMT severity measured by CMTSS (p = 0.379) and CMTES (p = 0.534). Patella alta (p = 0.0001), J-sign (p = 0.004), lateral patellar glide (p = 0.0001), generalised joint hypermobility (p = 0.001) and knee flexors weakness (p = 0.008) were associated with an increased risk of dislocation. Patella alta (p = 0.010) and lateral patellar glide (p = 0.028) were independent PF dislocation predictors.
Conclusions:
PF dislocation was common in this cohort with CMT and was associated with multiple risk factors. Future studies should be conducted to confirm the present findings so that the identified risk factors may be addressed by clinicians through preventive, supportive and corrective measures.
... The gold standard radiological assessment of the tibial tuberosity-trochlear groove (TTTG) distance, used in assessing lateral patellofemoral instability (PFI), is computed tomography (CT) or magnetic resonance imaging (MRI) measurement [1,2]. The TTTG is the distance in the axial plane between the trough of the trochlear groove and the apex of the tibial tuberosity, with larger distances associated with increased PFI and resultant patellofemoral disorders. ...
Background:
The tibial tuberosity-trochlear groove (TTTG) distance is used to assess patellofemoral instability (PFI) and the likelihood of the development of patellofemoral disorders. The current gold standard in the assessment of the TTTG is computed tomography (CT) or magnetic resonance imaging (MRI). The current image software used for viewing these CT images does not allow for easy assessment of the TTTG.
Aims:
This study presents a simple method to measure the TTTG on any image software, utilizing easily available and affordable stationary.
Methods:
Four consecutive patients with no known knee pathologies were selected from recent studies at our institution. Their TTTGs were measured using this study's method and validated using the standard, freely available image analysis software Fiji. Pre-defined anatomical landmarks were located and marked using adhesive pieces of paper. The TTTG was defined as the distance between parallel lines through the apex of the tibial tuberosity and trough of the trochlear groove, where each of these lines is perpendicular to the Dorsal Condylar Line.
Results:
The TTTG measured using this study's method was found to be in agreement with the measurements made using Fiji software.
Conclusions:
This study demonstrates that the TTTG can be simply and quickly assessed using readily available and affordable stationery, without the need for expensive or complex secondary analysis software. This could allow for the assessment of PFI in the outpatient clinic whilst the patient is present, offering valuable assistance to the orthopaedic surgeon in clinical decision making.
... Alt ekstremitenin hareketi esnasında patellanın stabil kalmasına etki eden dört faktör mevcuttur; bunlar alt ekstremitenin dizilimi, eklem yüzlerinin anatomik yapısı, dinamik kas kuvvetleri ve patellanın çevresinde yer alan statik bağlardır. [4] Patella çıkığı tipik olarak femurun, iç rotasyon ve adduksiyona, tibianın, dış rotasyon ve abdüksiyona zorlandığı pozisyonda meydana gelir. [5] Çıkığın oluştuğu bu pozisyonda ayak yerde sabit durumdayken diz ekleminde fleksiyon ve valgus zorlaması mevcuttur. ...
... [9] Troklear displazi PF instabilite etyolojisinde önemli yer oynamasına karşın cerrahi tedavide bu patolojiye yönelik girişimler çok sık uygulanan cerrahi girişimler değildir. [4] Bunun nedeni trokleoplasti ameliyatlarının teknik olarak zor olması, rapor edilen subkondral kemik hasarları ve bu hasarın troklear artroza zemin hazırlamasıdır. [12] Buna karşın trokleoplasti ameliyatlarının patellanın sulkustaki seyrini düzelttiği ve PF çıkığı başarıyla engellediği de bildirilmiştir. ...
... Kuadriseps kasının bir parçası olan VMO, medial intermusküler septum, adduktör longus ve adduktör magnus tendonlarından başlayarak patellanın superomedial kısmına, MPFL'ye ve medial retinakuluma, yaklaşık 47°'lik bir açıyla yapışır. [4] Vastus medialis oblikus, lateral instabiliteye karşı koyan, patellayı mediale ve posteriora çeken bir kuvvet oluşturur. Bu yapı patellası çıkan olgularda sıklıkla yaralanır ve tekrarlayan çıkıklar için risk oluşturur. ...
... The normal position of the patella is essential in establishing an ideal knee motion and stability. Anatomical alterations of the knee joint cause instability and further influence the patient's daily activity and quality of life [20]. A satisfactory functional outcome is obtained by maintaining proper intraoperative techniques, including ensuring an accurate determination of patellar height. ...
BACKGROUND: Neglected patellar tendon rupture is an extremely rare case among orthopedic injuries that severely compromises the function of the extensor mechanism of the knee. Therefore, a prompt and accurate diagnosis of a ruptured patellar tendon are a key to efficacious management, because a treatment delay is often associated with unsatisfactory functional outcomes.
CASE PRESENTATION: We report the case of an adult male patient with traumatic patellar tendon rupture after 9 months of a motorcycle accident. The patient underwent reconstruction surgery using semitendinosus and gracilis tendon augmentation. This procedure restores the anatomical position of the patella and prevents extensor lag. At a 3-month follow-up, a full recovery of the structure and function of the extensor mechanism was perceived. The patient could return to normal daily activities following rehabilitation protocol.
CONCLUSION: Semitendinosus and gracilis tendon autograft is the technique of choice to be applied in the surgical reconstruction of neglected patellar tendon rupture.
... 11 This is due to the fact that the patella does not engage in the trochlear groove until a high knee flexion angle in patients with patella alta, thereby increasing the risk of instability. 10,12,13 Hence, measurement of patellar height is an important technique for evaluating the risk of patellar instability and determining subsequent treatment options. 11,[14][15][16] There are a number of methods to radiographically measure patellar height, including the InsalleSalvati (IS), modified InsalleSalvati (MIS), CatoneDeschamps Index (CDI), and BlackburneePeel (BP). ...
Purpose
To compare the measurements of the Caton–Deschamps index on preoperative magnetic resonance imaging and radiographs of patients undergoing operative management of patellar instability.
Methods
Patients who underwent primary medial patellofemoral ligament reconstruction and/or tibial tubercle osteotomy between January 2015 and November 2019 were assessed. Caton–Deschamps indices were measured by 3 independent reviewers on both radiographs and magnetic resonance imaging. Intra- and interclass correlation coefficients and a Bland–Altman analysis were calculated to assess inter-rater reliability and measurement agreement between radiographic and magnetic resonance imaging.
Results
Seventy-two patients (73 knees) were identified. The average Caton–Deschamps index was 1.23 ± 0.18 on radiograph and 1.26 ± 0.18 on magnetic resonance imaging. Strong inter-rater reliability was observed between reviewers for both radiographic and magnetic resonance imaging Caton–Deschamps indices (intraclass correlation coefficients 0.700 and 0.715, respectively). Pooled observer measurements revealed a moderate agreement between radiographic and magnetic resonance imaging for patella to tibia distance, weak agreement for patellar articular cartilage distance, and strong agreement for the Caton–Deschamps index (intraclass correlation coefficients 0.687, 0.485, and 0.749, respectively). Bland–Altman analysis demonstrated a mean difference in Caton–Deschamps index of –0.03 ± 0.15 (95% limits of agreement: –0.29 to 0.23) between radiographic and magnetic resonance imaging, meaning that Caton–Deschamps indices were on average 0.03 lower on radiographic than on magnetic resonance imaging.
Conclusions
The Caton–Deschamps index has strong agreement between radiographic and magnetic resonance imaging in patients undergoing patellar stabilization surgery. Either modality can be reliably used to preoperatively assess patellar height.
Level of Evidence
Level IV, diagnostic case series.
... The force exerted by the quadriceps tendon on the patella is naturally lateral to the midline and, unchecked, can result in patella dislocation. Stability against excessive lateral pull is conferred by the medial patellofemoral ligament and vastus medialis oblique, both of which insert onto the medial aspect of the patella (Greiwe et al, 2010). Given the direction of pull of the quadriceps tendon, it is easy to see why deficiency or disruption of the medial patellofemoral ligament or vastus medialis oblique could result in patella dislocation and why most patella dislocations are lateral in direction (Figure 1). ...
Patella dislocation is one of the most common knee injuries, accounting for 3% of acute knee injuries. Despite its prevalence, patella dislocation is often missed, with a haemarthrosis often the only sign, albeit a non-specific one. A thorough history and examination are necessary to identify patella dislocation and its potential causes. Investigations should include cross-sectional imaging to evaluate both osseous and soft tissue structures in order to guide management. Management in the acute setting is normally non-operative, but damage to structural supports, osteochondral defects or recurrent dislocation should prompt consideration of operative treatment. Operative treatment should address the soft tissue stabilisers and/or osseus deformities that predispose to, or occur secondary to, patella dislocation.
... Bei der Patella alta kommt es in den frühen Knieflexionsgraden zu einem verspäteten Kontakt der Kniescheibe mit der Trochlea femoris. Beides führt zu Instabilität [4]. Zusätzlich ist bei der Patella alta die patellofemorale Kontaktfläche re-duziert, wodurch das Risiko für Arthrose steigt [8]. ...
Zusammenfassung
Das Operationsziel des hier dargestellten Verfahrens ist eine Distalisierung der Tuberositas tibiae. Dieser Eingriff ist bei Patienten mit einer symptomatischen Patella alta indiziert, zum Beispiel bei Kniescheibeninstabilität. Die Osteotomie erfolgt v‑förmig. Der bei der Distalisierung gewonnene Knochenblock wird als proximales Widerlager eingebracht. Dadurch wird die mediolaterale und proximale Stabilität verbessert. Außerdem wird die Oberfläche vergrößert, was eine bessere Knochenheilung ermöglicht. Bei dem vom Operateur behandelten Patientenkollektiv von 10 Patienten ist es bei dieser Technik zu keiner sekundären Dislokation gekommen.
... In the early and late stage, the variation ranges of all six parameters were larger than those in the middle stage, with a larger standard deviation among subjects. This was because the patella had not been captured by the trochlear groove and was only regulated by the soft tissue before 30°f lexion [16], while in the late stage, the fluctuation of the FHA was attributed to the transformation of the patella moving away from the circular pathway in deep flexion as it moved onto the bilateral femoral condyles [9]. The variations in the FHA decreased in the middle stage, as a result of the femoral condyles enhancing patellar movement after it entered the trochlear groove [16]. ...
... This was because the patella had not been captured by the trochlear groove and was only regulated by the soft tissue before 30°f lexion [16], while in the late stage, the fluctuation of the FHA was attributed to the transformation of the patella moving away from the circular pathway in deep flexion as it moved onto the bilateral femoral condyles [9]. The variations in the FHA decreased in the middle stage, as a result of the femoral condyles enhancing patellar movement after it entered the trochlear groove [16]. Clinically, trochlear dysplasia is one of the common causes of patellar instability [17,18]. ...
... Because the TEA is an anatomic marker which is easy to identify and is widely used clinically, and the present results showed that the patellar FHA was close to the TEA, it would be reliable to assess the FHA with the TEA as a reference. The insertion point of the medial and lateral retinaculum of the patellofemoral joint was near the sulcus of the medial epicondyle and the prominence of the lateral epicondyle, respectively [16], which explained why the FHA was close to the TEA. To date, the TEA has been regarded as an essential reference when installing the trochlear prosthesis in patellofemoral arthroplasty, and relatively successful clinical results have been achieved [25], which verifies the close relationship between the patellar FHA and TEA. ...
Background
To manage patellofemoral joint disorders, a complete understanding of the in vivo patellofemoral kinematics is critical. However, as one of the parameters of joint kinematics, the location and orientation of the patellofemoral finite helical axis (FHA) remains unclear. The purpose of this study is to quantify the location and orientation of the patellar FHA, both in vivo and non-invasively at various flexion angles, and evaluate the relationship of the FHA and the trans-epicondylar axis (TEA).
Methods
The magnetic resonance (MR) images of 18 unilateral knees were collected at full extension, 30°, 60°, 90°, and maximum angle of knee flexion. Three-dimensional models of the knee joint at different flexion angles were created using the MR images, and then used to calculate the patellar tracking and FHA with a spline interpolation algorithm. By using a coordinate system based on the TEA, the FHA tracking was quantified. Six parameters concerning the location and orientation of the patellar FHA were analysed.
Results
The average patellar FHA drew an L-shaped tracking on the midsagittal plane moving from the posteroinferior to the anterosuperior side of the TEA with knee flexion. Before 90° flexion, the patellar rotational radius decreased slightly, with an average value of 5.65 ± 1.09 cm. During 20° to 90° knee flexion, the average angle between the patellar FHA and the TEA was approximately 10° and that between the FHA and the coronal plane was maintained at about 0°, while that between the FHA and the level plane fluctuated between − 10° and 10°.
Conclusions
This study quantitatively reported the continuous location and direction of the patellar FHA during knee flexion. The patellar FHA was close to but not coincident with the femoral TEA both in location and orientation, and the patellar rotational radius decreased slightly with knee flexion. These findings could provide a clear direction for further studies on the difference in patellofemoral FHA among various types of patellofemoral disorders, and provide a foundation for the application of FHA in surgical evaluation, preoperative planning and prosthesis design, thereby assisting in the diagnosis and treatment of patellofemoral disorders.
