[Finite element biomechanical analysis of coronal alignment correction in unicompartmental knee arthroplasty for severe varus deformity].

OBJECTIVE: To investigate the effects of different correction angles of the coronal lower limb alignment (represented by the hip-knee-ankle, HKA ) on the stress of prostheses and ligaments in patients with severe genu varum undergoing unicompartmental knee arthroplasty (UKA), and to clarify the optimal reconstruction strategy for postoperative coronal alignment. METHODS: Based on the computed tomography (CT) and full-ength lower limb X-ray data of 12 patients with severe genu varum (HKA angle:15°to 20°), individualized three-dimensional finite element models were established. By adjusting the HKA angle, four types of UKA correction models were constructed with HKA angles of 0° (neutral), 3°, 6°, and 9°of varus. Seven physiological knee postures (erect, varus, valgus, internal rotation, external rotation, flexion, and hyperextension) were simulated, with a vertical load of 750 N and a bending moment of 7.5 N·m applied. The maximum stress values of the femoral prosthesis, tibial prosthesis, polyethylene insert, medial/lateral collateral ligaments(MCL/LCL), and anterior/posterior cruciate ligaments(ACL/PCL) were calculated. The Mann-Whitney U test was used to analyze the biomechanical differences among different correction angles and postures. RESULTS: