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Postoperative limb length discrepancy measurement: Significant limb length discrepancy (80.77 − 82.02 = 12.5 mm limb length discrepancy)
Source publication
PurposeLimb length discrepancy (LLD) has been related to inferior outcomes after total hip arthroplasty (THA), but few studies have dealt with the LLD in primary total knee arthroplasty (TKA). The aims of the study were to examine the incidence of LLD after TKA and how it can influence in the outcomes scores.
Methods
We analysed preoperative, posto...
Citations
... The patellofemoral joint can be affected by a PTO. The courses of the patella can indeed shift in the sagittal and coronal planes and be influenced by rotational changes [34,45]. A medial opening PTO decreases the height of the patella, while a lateral closing PTO may increase it [46,47]. ...
... Limb length discrepancies (LLD) may cause long term osteoarthritis, scoliosis, and gait abnormalities [73]. Hinarejos et al. reported that the clinically significant LLD lies at 10 mm [45], while other authors reported that differences of more than 20 mm can be compensated [74]. An attempt was made to generate a mathematical model allowing for patient-specific estimation of limb length change. ...
Proximal tibial osteotomy (PTO) is an effective procedure for active and young adult patients with symptomatic unicompartmental osteoarthritis and malalignment. They were considered technically demanding and prone to various complications related to the surgical technique, biomechanical or biological origin. Among the most important are hinge fractures and delayed or non-healing, neurovascular complications, loss of correction, implant-related problems, patellofemoral complaints, biological complications and changes in limb length. Being aware of these problems can help minimizing their prevalence and improve the results of the procedure.
The aim of this narrative review is to discuss the potential complications that may occur during and after proximal tibial osteotomies, their origin and ways to prevent them.
... In a literature search, there seems to be a lack of a definitive consensus on where the threshold lies for a clinically significant LLD. However, Hinarejos et al. and Khamis et al. currently report an estimated clinically significant LLD that lies at 10 mm [9,11]. Conversely, some outlying manuscripts in the literature suggest that LLD > 20 mm can still be compensated [19]. ...
... Hinarejos et al. [9] and Khamis et al. reviewed and found evidence to support that gait deviations occur starting from a discrepancy of > 1 cm [11]. In addition, Gordon et al. reviewed studies dealing with the effects of LLD and reported that there is a consensus that LLD > 2.0 cm often result in pathologies [8]. ...
Purpose:
This study aims to assess the significance of post-operative change in limb length in medial opening wedge high tibial osteotomy (MOWHTO), and evaluate the correlation between correction angles and changes in limb length. We hypothesize that opening wedge height and correction angles directly correlate to changes in limb length.
Methods:
The medical records and radiographs of 91 MOWHTO patients were retrospectively evaluated for relevant radiographical parameters both pre- and post-operatively. The exclusion criteria are: (i) concurrent distal femur osteotomy in the same setting, (ii) other previous unilateral lower limb surgeries prior to MOWHTO and (iii) failure to follow-up with post-operative radiographs. A linear regression model was performed and a line of best fit, Pearson's correlation coefficient (r) and coefficient of determination (R2) were computed. Chi-squared test was also performed, and results with P < 0.05 were considered statistically significant.
Results:
There is a statistically significant increase in post-MOWHTO limb length (Absolute Δ = 4.3 ± 2.86 mm, % Δ = 0.652% ± 0.434%, p < 0.001). There was no significant difference in the limb length change between patients with larger (> 8 mm) and smaller (< 8 mm) opening widths. There was a weakly positive correlation between limb length change versus actual (R2 = 0.140, 95%CI [-0.068, 0.336]) and planned correction angles (R2 = 0.196, 95%CI [-0.012, 0.387]).
Conclusion:
In conclusion, post-MOWHTO change in limb length is statistically significant, but the clinical significance is minimal. Further studies are required to assess other factors. Development of a reliable mathematical model that predicts post-MOWHTO limb length change would be useful in predicting the anatomical outcomes.
Level of evidence:
Level III. Retrospective Cohort Study.
... Some patients may suffer from leg length discrepancy caused by leg length change after operation, which can reduce the patient's satisfaction with the operation. In addition, post-operative leg length discrepancy may result in many unwanted effects, such as poor recovery, limping, acceleration of contralateral knee osteoarthritis, and lower back pain [2][3][4]. As the total knee arthroplasty (TKA) is the most common operation for end-stage knee osteoarthritis, most of the research have been focused on the leg length change after TKA. ...
Background
Leg length change after knee arthroplasty is one of the most concerned problems for patients and doctors. However, as there was only one literture focused on the leg length change after unicompartmental knee arthroplasty, we aimed to clarify the leg length change after medial mobile-bearing unicompartmental knee arthroplasty (MOUKA) using a novel double calibration method.
Methods
We enrolled patients who underwent MOUKA and had taken full-length radiographs in a standing position prior to and at 3 months after the operation. We eliminated the magnification by a calibrator and corrected the longitudinal splicing error by measuring the femur and tibia lengths before and after operation. Perceived leg length change was collected 3 months after operation. Bearing thickness, preoperative joint line convergence angle, preoperative and postoperative varus angles, flexion contracture and Oxford knee score (OKS) were also collected.
Results
From June 2021 to February 2022, 87 patients were enrolled.76 (87.4%) of them showed an increase with an average of 0.32 cm (range from -0.30 cm to 1.05 cm) in leg length change. The lengthening was strongly correlated with the degree of varus deformity and its correction value (r = 0.81&0.92, P < 0.01). Only 4 (4.6%) patients perceived leg length lengthening after operation. There was no difference in OKS between the patients who had an increase in leg length and those who had a decrease (P = 0.99).
Conclusions
Majority of patients only experienced a slight increase in leg length after MOUKA, and such an increase did not affect patients’ perception and short-term function.
... Some studies have focused on radiological results to predict clinical outcomes and satisfaction after knee replacement [2][3][4], especially those aiming to compare robotic-assisted surgery and conventional surgery [5,6]. Nevertheless, these studies focus mainly on anteroposterior views, sometimes lateral views, but less frequently on the axial view of the patella or the rotation of the femoral component. ...
Background
Total knee arthroplasty (TKA) is a cost-effective treatment for the end-stage of knee osteoarthritis. Despite the improvements in this surgery, a significant percentage of patients still report dissatisfaction after knee arthroplasty. Radiological results have been used to predict clinical outcomes and satisfaction after knee replacement. This study aims to evaluate the concordance of a set of radiographic views to assess alignment on total knee arthroplasty.
Methods
A concordance study was designed with 105 patients (130 TKA) that underwent conventional total knee arthroplasty cruciate-retaining design recruited for the study and scheduled for their annual radiograph control. Measurements were performed on the following radiograph after total knee replacement: full-length standing anteroposterior and lateral radiograph, anteroposterior standing, lateral and axial knee view, and the knee "seated view". A musculoskeletal radiologist and a knee surgeon were recruited to perform the radiological measurement and then estimate the interobserver agreement.
Results
There was an excellent correlation between Limb Length (LL), Hip-knee-ankle angle (HKA), Sagittal mechanical tibial component alignment (smTA), extension lateral and medial joint space (eLJS and eMJS), 90º flexion lateral and medial joint space (fLJS and fMJS) and Sagittal anatomic lateral view tibial component alignment (saLTA); the good correlation between Mechanical lateral femoral component alignment (mLFA), Sagittal anatomic tibial component alignment (saTA), Sagittal anatomic lateral view femoral component alignment 2 (saLFA2), Patella Height (PH); and moderate to poor correlation for the rest of measurements.
Conclusion
Excellent and good concordance can be achieved for radiographic measurements in different knee views to assess results after TKA. These findings must encourage future studies to address functional and survival outcomes using all knee views and not just one plane.
... Only a few studies in the literature evaluated LLD after TKA [5,6,10,14,15,[17][18][19][20][21][22][23]. While the western literature reported minimal LLD (< 5.5 mm) that has no clinical relevance [6,[18][19][20][21]23], others have reported substantial limb length discrepancy (≥ 10 mm) following unilateral TKA [10,14,15,17]. ...
... Only a few studies in the literature evaluated LLD after TKA [5,6,10,14,15,[17][18][19][20][21][22][23]. While the western literature reported minimal LLD (< 5.5 mm) that has no clinical relevance [6,[18][19][20][21]23], others have reported substantial limb length discrepancy (≥ 10 mm) following unilateral TKA [10,14,15,17]. The LLD issue is more alarming in India and few other Asian countries because of the late presentation, advanced disease with bone defect, ligamentous laxity and proceeding for unilateral TKA despite severe bilateral disease. ...
... The preoperative LLD and perceived LLD in TKA have recently gained more importance [18][19][20]. However, many studies have not evaluated these aspects. ...
Abstract Background Limb length alteration following total knee arthroplasty (TKA) has been under-reported. Few studies have shown a significant association between limb length discrepancy (LLD) and poor functional outcome. This prospective study evaluated the impact of radiographic and perceived LLD on functional outcome in TKA. The variables affecting LLD were also evaluated. Methods The preoperative and postoperative limb lengths of TKA patients (112 knees, 81 patients, KL grade ≥ 3) were measured in full-length digital radiographs. The Hip-Knee-Ankle (HKA) angles were also measured. The functional outcome (Western Ontario and McMaster Universities Arthritis Index) and perception about LLD were evaluated after six months. Results The mean preoperative radiographic LLD in the unilateral and bilateral TKA groups was 0.75 cm ± 0.60 cm and 0.58 cm ± 0.52 cm (P = 0.197), respectively. Similarly, postoperative LLD was 0.76 cm ± 0.85 cm in the unilateral group and was 0.59 cm ± 0.92 cm (P = 0.402) in the bilateral group. Only 19.7% of patients had postoperative radiographic LLD of ≥ 10 mm, and 80.2% of patients had LLD of
... Chinnappa et al. found that perceived LLD was associated with decreased satisfaction and poorer functional scores but was not associated with radiographic LLD [13]. Hinarejos et al. found postoperative LLD as described by ≥10 mm to have significant worse functional outcome in KSS [15]. Kim et al. found that >15 mm LLD computer-assisted TKA showed lower functional outcome scores, although the authors state that the correlation was low [16]. ...
Introduction:
Expectations for limb length differences after TKA are important for patient perception and outcomes. Limb length discrepancies may occur due to postoperative leg length increases, which can lead to decreased patient functionality and satisfaction and even possible litigation. The purpose of this study is to examine the frequency and extent of limb lengthening among various preoperative deformities and between two different implant systems.
Methods:
Preoperative and postoperative full-length standing radiographs were obtained between August 2018 and August 2019 to measure mechanical axis and limb length of operative limbs. Demographic information such as age, sex, and BMI was also collected. Patients were grouped into categories for pre- and postoperative subgroup analysis: valgus, varus, customized implant, and conventional implant. Regression analysis was performed to evaluate significant relationships.
Results:
Of the 121 primary TKAs analyzed, 62% of the knees showed an increase in limb length after TKA, with an average lengthening of 5.32 mm. Preoperative varus alignment was associated with a mean lengthening of 3.14 mm, while preoperative valgus alignment was associated with a mean lengthening of 16.2 mm. Overall, there were no statistically significant differences in limb lengths pre- and postoperatively (p = 0.23) and no significant changes in limb length for any subgroup. Further, no variables were associated with limb length changes (p = 0.49), including the use of customized implants (p = 0.2).
Conclusions:
Limb lengthening after TKA is common and, on average, occurs more significantly in valgus knees. No significant difference in limb lengthening could be demonstrated using customized over conventional implants. Preoperative counseling is important to manage patient expectations.
... There may be precipitations of low back pain, hip pain because of arthritic changes and also compensatory pelvis and spinal curvature changes [6][7][8][9][10] . There are limited studies in literature till date evaluating LLD after TKA [11][12][13][14][15][16][17][18] . While few studies reported LLD as a common occurrence after TKA [11][12][13][14] , others reported that radiographic LLD is uncommon [15][16][17] . ...
... There are limited studies in literature till date evaluating LLD after TKA [11][12][13][14][15][16][17][18] . While few studies reported LLD as a common occurrence after TKA [11][12][13][14] , others reported that radiographic LLD is uncommon [15][16][17] . Recently, few researchers have reported radiographic LLD of ≥ 10 mm as a clinically relevant change [16,17] . ...
... While few studies reported LLD as a common occurrence after TKA [11][12][13][14] , others reported that radiographic LLD is uncommon [15][16][17] . Recently, few researchers have reported radiographic LLD of ≥ 10 mm as a clinically relevant change [16,17] . Contrary to it, the perceived LLD has been given more weightage in a few studies [15,16] . ...
BACKGROUND
Limb length discrepancy (LLD) after total knee arthroplasty (TKA) has been considered as one of the reasons for the unsatisfactory outcome. However, there is no consensus about the extent of LLD that can be considered as clinically relevant.
AIM
To evaluate the incidence of radiographic LLD and its impact on functional outcome following TKA.
METHODS
All randomized-controlled trial and observational studies on LLD in TKA, published till 22nd June 2020, were systematically searched and reviewed. The primary outcome was “limb lengthening or LLD after TKA”. The secondary outcomes included “assessment of LLD in varus/valgus deformity” and “impact of LLD on the functional outcome”.
RESULTS
Of 45 retrieved studies, qualitative and quantitative assessment of data was performed from eight studies and six studies, respectively. Five studies (n = 1551) reported the average limb lengthening of 5.98 mm. The LLD after TKA was ranging from 0.4 ± 10 mm to 15.3 ± 2.88 mm. The incidence of postoperative radiographic LLD was reported in 44% to 83.3% of patients. There was no difference in the preoperative and postoperative LLD (MD -1.23; 95%CI: -3.72, 1.27; P = 0.34). Pooled data of two studies (n = 219) revealed significant limb lengthening in valgus deformity than varus (MD -2.69; 95%CI: -5.11, 0.27; P = 0.03). The pooled data of three studies (n = 611) showed significantly worse functional outcome in patients with LLD of ≥ 10 mm compared to < 10 mm (standard MD 0.58; 95%CI: 0.06, 1.10; P = 0.03).
CONCLUSION
Limb lengthening after TKA is common, and it is significantly more in valgus than varus deformity. Significant LLD (≥ 10 mm) is associated with suboptimal functional outcome.
... There may be precipitations of low back pain, hip pain because of arthritic changes and also compensatory pelvis and spinal curvature changes [6][7][8][9][10] . There are limited studies in literature till date evaluating LLD after TKA [11][12][13][14][15][16][17][18] . While few studies reported LLD as a common occurrence after TKA [11][12][13][14] , others reported that radiographic LLD is uncommon [15][16][17] . ...
... There are limited studies in literature till date evaluating LLD after TKA [11][12][13][14][15][16][17][18] . While few studies reported LLD as a common occurrence after TKA [11][12][13][14] , others reported that radiographic LLD is uncommon [15][16][17] . Recently, few researchers have reported radiographic LLD of ≥ 10 mm as a clinically relevant change [16,17] . ...
... While few studies reported LLD as a common occurrence after TKA [11][12][13][14] , others reported that radiographic LLD is uncommon [15][16][17] . Recently, few researchers have reported radiographic LLD of ≥ 10 mm as a clinically relevant change [16,17] . Contrary to it, the perceived LLD has been given more weightage in a few studies [15,16] . ...
BACKGROUND
Limb length discrepancy (LLD) after total knee arthroplasty (TKA) has been
considered as one of the reasons for the unsatisfactory outcome. However, there is
no consensus about the extent of LLD that can be considered as clinically relevant.
AIM
To evaluate the incidence of radiographic LLD and its impact on functional
outcome following TKA.
METHODS
All randomized-controlled trial and observational studies on LLD in TKA,
published till 22nd June 2020, were systematically searched and reviewed. The
primary outcome was “limb lengthening or LLD after TKA”. The secondary
outcomes included “assessment of LLD in varus/valgus deformity” and “impact
of LLD on the functional outcome”.
RESULTS
Of 45 retrieved studies, qualitative and quantitative assessment of data was performed from eight studies and six studies, respectively. Five studies (n = 1551)
reported the average limb lengthening of 5.98 mm. The LLD after TKA was
ranging from 0.4 ± 10 mm to 15.3 ± 2.88 mm. The incidence of postoperative
radiographic LLD was reported in 44% to 83.3% of patients. There was no
difference in the preoperative and postoperative LLD (MD -1.23; 95%CI: -3.72,
1.27; P = 0.34). Pooled data of two studies (n = 219) revealed significant limb
lengthening in valgus deformity than varus (MD -2.69; 95%CI: -5.11, 0.27; P =
0.03). The pooled data of three studies (n = 611) showed significantly worse
functional outcome in patients with LLD of ≥ 10 mm compared to < 10 mm
(standard MD 0.58; 95%CI: 0.06, 1.10; P = 0.03).
CONCLUSION
Limb lengthening after TKA is common, and it is significantly more in valgus
than varus deformity. Significant LLD (≥ 10 mm) is associated with suboptimal
functional outcome.
Background: Anterior knee pain (AKP) following total knee arthroplasty (TKA) with patellar preservation is a common complication that significantly affects patients' quality of life. This study aimed to develop a machine learning model to predict the likelihood of developing AKP after TKA using radiological variables. Methods: A cohort of 131 anterior stabilized TKA cases (105 patients) without patellar resurfacing was included. Patients underwent a follow-up evaluation with a minimum one-year follow-up. The primary outcome was AKP, and radiological measurements were used as predictor variables. There were two observers who made the radiological measurement, which included lower limb dysmetria, joint space, and coronal, sagittal, and axial alignment. Machine learning models were applied to predict AKP. The best-performing model was selected based on accuracy, precision, sensitivity, specificity, and Kappa statistics. Python 3.11 with Pandas and PyCaret libraries were used for analysis.
Results: A total of 35 TKA had AKP (26.7%). Patient-reported outcomes were significantly better in the patients who did not have AKP. The Gradient Boosting Classifier (GBC) performed best for both observers, achieving an area under the curve (AUC) of 0.9261 and 18 0.9164, respectively. The mechanical tibial slope was the most important variable for predicting AKP. The Shapley test indicated that high/low mechanical tibial slope, a shorter operated leg, a valgus coronal alignment, and excessive patellar tilt increased AKP risk.
Conclusions: The results suggest that global alignment, including sagittal, coronal, and axial alignment, is relevant in predicting AKP after TKA. These findings provide valuable insights
for optimizing TKA outcomes and reducing the incidence of AKP.
Keywords: Total Knee Arthroplasty, Anterior Knee Pain, radiological measurement, Quality of Life.
