Medial Tibial Plateau depth is a key morphological determinant of cartilage lesion severity in anteromedial knee osteoarthritis.

Abstract

Anteromedial osteoarthritis (AMOA) is characterized by focal cartilage loss on the anteromedial tibial plateau. While medial tibial plateau depth (MTPD) is known to influence knee biomechanics, its direct relationship with cartilage lesion severity in AMOA remains unclear. This study investigated whether a shallower MTPD is associated with more severe cartilage damage in AMOA. This retrospective study included 240 patients with AMOA. MTPD and other radiographic parameters (hip-knee-ankle angle - HKAA, joint line convergence angle - JLCA, posterior tibial slope - PTS) were measured from radiographs and MRI. Medial meniscal status (tear, extrusion) was also assessed on MRI. Cartilage lesion severity was assessed arthroscopically and graded using the International Cartilage Repair Society (ICRS) classification system. Statistical analyses included correlation, receiver operating characteristic (ROC) curve analysis, and multivariate regression to identify factors associated with cartilage damage. A shallower MTPD was significantly correlated with higher ICRS grades on both the medial tibial plateau (MTP) and medial femoral condyle (MFC) (r ≈ -0.43, p < 0.001). ROC analysis showed MTPD had acceptable discriminative ability for identifying ICRS grade >1 lesions within this cohort (AUC: 0.729 for MTP, 0.716 for MFC). Multivariate regression confirmed MTPD as an independent factor associated with higher ICRS grade, alongside higher age, BMI, meniscal extrusion, and JLCA, and lower HKAA. PTS was not significantly associated with ICRS grade. A shallower medial tibial plateau depth is significantly associated with more severe cartilage lesions in anteromedial knee osteoarthritis. This morphological feature may contribute to the pathomechanics of AMOA, and its assessment could aid in patient stratification. Further longitudinal studies are warranted to establish causality.