Static native tibial alignment in total knee arthroplasty optimises whole-body gait kinematics

To investigate the impact of static native tibial alignment in total knee arthroplasty (TKA) on whole-body postoperative gait biomechanics, comparing adjusted mechanical alignment (aMA) and inverse kinematic alignment (iKA).

Thirty patients undergoing primary TKA were included: 15 in the aMA group (17 knees) and 15 in the iKA group (19 knees), assessed 2 years post-surgery. A healthy control group of 15 participants, matched for age, sex and body mass index (BMI), was included. Postoperative spatiotemporal and kinematic gait parameters were measured using 3D motion capture during gait.

The aMA group demonstrated persistent knee flexion around midstance during the stance phase (p = 0.002, >10.00°), reduced knee flexion at swing onset (p = 0.011, -12.00°), and decreased ankle plantarflexion (p = 0.002, -8.00°). Additionally, the aMA group showed reduced hip extension (p < 0.001), increased anterior pelvic tilt (p < 0.001), exaggerated thorax flexion (p = 0.003) and altered elbow motion (p < 0.015). In contrast, the iKA group exhibited gait patterns more closely resembling healthy controls, with a greater range of motion (ROM) at the hip, knee and ankle, improved ankle and foot progression angles, and no differences in thorax posture or elbow angles compared to controls.

These findings underscore the integrated nature of gait biomechanics and suggest that subtle modifications to the knee joint line may contribute to widespread kinematic adaptations. Preserving static native tibial alignment through personalised surgical strategies may, therefore, enhance functional outcomes following TKA.

Level III.