Effect of tibiofemoral alignment on simulated knee contact forces during gait in mechanically and kinematically aligned total knee arthroplasty patients

The goal of the study was to apply a musculoskeletal knee model that considers individual tibiofemoral alignment (TFA) and to investigate its effect on knee contact force (KCF) during gait in mechanically (MA) and kinematically aligned (KA) total knee arthroplasty (TKA) patients. Total, medial, and lateral KCF was estimated from pre- and postoperative gait data of TKA patients (MA: n = 26, KA: n = 22). Preoperative KCF was compared between the generic and the adapted model using t-tests and statistical parametric mapping (SPM). The TFA-adapted model was then used to analyze pre- to postoperative differences in MA and KA patients. The factor of TFA increased estimates of KCF during the stance phase and led to higher peak contact forces (3-5%, p < 0.05). SPM analyses of pre- to postoperative KCF revealed no significant differences across the gait cycle, however, postoperative peak KCF was significantly increased in both groups (10-18%, p < 0.05). No group differences were observed when comparing KCF between MA and KA patients. Integrating TFA into the model led to higher estimations of KCF. Applying the adapted model, pre- to postoperative differences in KCF were the same for both TKA groups suggesting that both alignment techniques had comparable effects on knee loading post-TKA.