Increased medial posterior tibial slope is associated with patellofemoral cartilage lesions: A matched-pair...

The medial posterior tibial slope (MPTS) is a key anatomical parameter influencing knee joint biomechanics and load distribution. This study aimed to analyze whether the MPTS is associated with cartilage lesions in different anatomical regions, including the medial and lateral femoral condyles, the trochlea, and retropatellar surface.

Between 09/2013 and 02/2024, 501 patients with cartilage lesions of the knee underwent matrix-induced autologous chondrocyte implantation (MACI) at a single-center university hospital. After applying the eligibility criteria, 280 patients were included. Each case was matched to controls by age and sex using a 1:1 matching design. MPTS was measured independently by three blinded raters using the Dejour method, and the mean value was used for analysis. Inter-rater reliability was assessed via intraclass correlation coefficient (ICC). Subgroup analysis was performed according to lesion location (medial/lateral femoral condyle, trochlea, retropatellar) using a many-to-one matching design. Linear mixed-effect regression models accounting for age, sex, and the matched-set structure were used as the primary analyses; unpaired t-tests with Cohen's d effect sizes served as sensitivity analyses. Adjusted mean differences and model-based standardized mean differences were reported with 95% confidence intervals (CIs), and location-specific comparisons were adjusted for multiple testing.

The MACI group had a greater MPTS than matched controls (9.73° vs. 8.92°; adjusted mean difference: 0.80°; 95% CI: 0.32 to 1.27; p < 0.01). Inter-rater reliability was excellent (ICC = 0.921). In the location-specific analyses, greater MPTS values were observed in patients with retropatellar lesions (n = 100 vs. 200; adjusted mean difference, 0.92°; 95% CI: 0.05 to 1.80; adjusted p = 0.03) and trochlear lesions (n = 34 vs. 68; adjusted mean difference, 1.60°; 95% CI: 0.11 to 3.10; adjusted p = 0.03). No statistically significant differences were identified for medial (n = 73 vs. 146; adjusted mean difference: 0.15°; 95% CI: -0.87 to 1.17; adjusted p = 0.99) or lateral femoral condylar lesions (n = 36 vs. 72; adjusted mean difference, 1.01°; 95% CI: -0.44 to 2.46; adjusted p = 0.29). The unadjusted sensitivity analyses yielded consistent conclusions.

An increased MPTS was associated with cartilage lesions in the patellofemoral compartment but not in the femoral condyles. This suggests a compartment-specific relationship between MPTS and cartilage lesions in the knee joint. However, their clinical relevance remains uncertain.

III, Retrospective Matched Case-Control Study.