Biomechanical effects of LCWHTO vs. MOWHTO on medial meniscus posterior root repair: a finite element analysis

Whether isolated high tibial osteotomy (HTO) or HTO combined with medial meniscus posterior root (MMPR) repair is the optimal surgical treatment of MMPR tears remains controversial. This study compared the biomechanical effects of isolated HTO versus MMPR repair combined with medial open wedge HTO (MOWHTO) or lateral closed wedge HTO (LCWHTO) using finite element analysis (FEA). In this study, the MRI and CT data of the knee joint were used to create an FEA model. MOWHTO and LCWHTO simulations adjusted the mechanical axis to the Fujisawa point, with MMPR conditions simulated as intact, tear, or repaired. The ankle center was fixed and a 1000 N force was applied to the knee. In the LCWHTO models, the posterior tibial slope (PTS) decreased, whereas it increased in the MOWHTO models. Changes in the PTS following HTO influenced the stress distribution in the MMPR. HTO combined with MMPR repair showed a reduction in the maximum contact stress by 5.4-11.4% and increased contact area by 29.5-41.0% in the medial knee compartment relative to isolated HTO. This study demonstrated that MMPR repair combined with LCWHTO would be more protective against stress loading in the MMPR than MMPR repair combined with MOWHTO or isolated HTO.