Influence of Femoral Component Rotation on Patellar Tracking and Functional Outcome after Total Knee Arthroplasty

ABSTRACT Background: The rotational alignment of the femoral component may have an impact on patellar tracking and functional recovery after total knee arthroplasty (TKA). These associations were assessed in this study with the aid of postoperative imaging and functional outcomes. Materials and Methods: A prospective observational study of 75 patients who underwent primary TKA. Computed tomography was used to assess the degree of femoral rotation relative to the surgical transepicondylar axis, and rotation was classified as internal (<−3°), near neutral (−3° to +3°), or external (>+3°). Postoperative patellar tilt and translation were evaluated and Knee Society Score (KSS) and KOOS-JR were assessed at 12 months. Results: Internal, near-neutral, and external rotation occurred in 16, 48, and 11 patients, respectively. Mean patellar tilt decreased across these groups (11.4°, 8.3°, and 5.4°; p < 0.001), as did lateral translation (3.9, 2.6, and 2.0 mm; p = 0.004). Each additional degree of external rotation was independently associated with a 0.576° decrease in lateral tilt (p < 0.001). No independent association was found between femoral rotation and 12-month functional scores, while greater postoperative tilt was significantly associated with lower KSS and KOOS-JR scores. Conclusions: Femoral component rotation showed a significant association with patellar tracking, and postoperative patellar tilt showed a stronger independent association with functional recovery. Keywords: Total knee arthroplasty; Femoral component rotation; Patellar tracking; Patellar tilt; Functional outcomes.