Mid‐Term Outcomes of Navigation‐Assisted Primary Total Knee Arthroplasty Using Adjusted Mechanical Alignment

Objective The adjusted mechanical alignment (aMA) technique is an extension of conventional mechanical alignment (MA), which has rarely been reported. The purpose of this study was to evaluate mid‐term outcomes of navigation‐assisted total knee arthroplasty (TKA) using aMA. Methods This retrospective cohort study enrolled 63 consecutive patients (77 knees) who underwent navigation‐assisted TKA using aMA between September 2017 and October 2019. Fifty‐two consecutive patients (61 knees) who underwent TKA using MA during the same period were assessed as the controlled group. The demographic data and perioperative data were recorded. The parameters of resection and soft tissue balance including tibia resection angle, frontal femoral angle, axial femoral angle, joint line translation, medial and lateral gap in extension and flexion position were recorded. Radiographic parameters and functional scores including the Hospital for Special Surgery (HSS) score, Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) score, and Forgotten Joint Score‐12 (FJS‐12) were evaluated. Surgery‐related complications were recorded. The average follow‐up was 3.5 years, with a minimum of 2.4 years. Results The frontal femoral angle was 2.55° ± 1.08° in aMA group versus 0.26° ± 0.60° in MA group (p