Significant influence of rotational limb alignment parameters on patellar kinematics: an in vitro study

Component malrotation has a major impact on patellar kinematics in total knee arthroplasty. The influence of natural rotational limb alignment on patellar kinematics is unclear so far. Based on recent clinical investigations, we hypothesized that rotational limb alignment significantly influences patellar kinematics.

Patellar kinematics of ten cadaveric knees was measured using computer navigation during passive motion. Data were correlated with different rotational limb alignment parameters of preoperative CT scans.

Femoral antetorsion showed a significant influence on patellar rotation, while tibial tubercle-posterior cruciate ligament distance additionally displayed a significant influence on patellar mediolateral shift (p < 0.05). Femoral posterior condylar angle was sensitive to patellar epicondylar distance, rotation and tilt (p < 0.05). Patellar rotation was influenced by five out of eight rotational limb alignment parameters (p < 0.05).

Rotational limb alignment should be paid more attention in terms of clinical evaluation of patellar tracking and future biomechanical and clinical investigations.