Target weight-bearing line after medial open-wedge high tibial osteotomy: A finite element analysis of meniscal and cartilage biomechanics.

Abstract

High tibial osteotomy (HTO) unloads the medial compartment by shifting the weight-bearing line (WBL) laterally. This finite element (FE) study quantified how progressive WBL lateralization redistributes stresses in tibiofemoral cartilage and the meniscus and explored a stress-based target range under defined model assumptions. A subject-specific full-length lower-limb FE model was reconstructed from CT and knee MRI of a healthy adult in neutral alignment (WBL = 50%). Progressive valgus alignments corresponding to WBL values from 50% to 100% of the tibial plateau width were generated. A compressive load representing body weight during level walking (1 BW, 600 N) was applied. Mean and peak von Mises stresses in tibiofemoral cartilage and the meniscus were compared across WBL conditions. As WBL increased, stresses shifted laterally, with rising stresses in the lateral tibial cartilage and lateral meniscus. Meniscal stress concentration moved from the body toward the anterior and posterior horns, with earlier concentration in the posterior horn. A marked increase in lateral-compartment stress was observed when WBL approached 64%, and further lateralization led to additional stress elevation. Progressive WBL lateralization increased the mechanical burden in the lateral compartment in this FE model. A WBL target around 64% appeared biomechanically favorable for balancing medial unloading against lateral stress elevation under the current assumptions. Clinical application should consider patient-specific lateral compartment and meniscal status and requires validation in pathological cohorts.