Spatiotemporal Gait Parameters in Fixed Versus Rotating Bearing Total Knee Arthroplasty: A Prospective 24-Month Longitudinal Study.

Background/

Objectives

The clinical superiority of rotating-bearing (RB) versus fixed-bearing (FB) total knee arthroplasty (TKA) remains controversial despite the proposed biomechanical advantages of mobile-bearing designs. Objective gait assessment with inertial measurement units (IMUs) provides a measurable view of functional recovery that may complement patient-reported outcome measures (PROMs). This study compared spatiotemporal gait parameters between FB and RB TKA over 24 months.

Methods

This prospective longitudinal comparative study enrolled 57 patients undergoing primary unilateral TKA for end-stage knee osteoarthritis. Spatiotemporal gait parameters (gait velocity, cadence, and stance-phase duration) were measured using wireless IMUs (G-WALK system) at 6, 12, and 24 months post-surgery. WOMAC and the 10-point Geriatric Locomotive Function Scale (GLFS-10P) were assessed at 12 and 24 months. Group, time, and Group × Time effects were analyzed using linear mixed-effects models.

Results

Both groups improved during follow-up, with performance largely plateauing between 12 and 24 months. At 24 months, there were no significant differences between groups in gait velocity (FB 1.17 vs. RB 1.16 m/s; p = 0.65), cadence (99.8 vs. 97.4 steps/min; p = 0.72), or stance-phase duration (59.3% vs. 59.0%; p = 0.82). Group × Time interactions were not significant across gait outcomes. WOMAC and GLFS-10P improved similarly in both groups (p > 0.05). Cadence was inversely correlated with the WOMAC function subscale at 24 months (rho = -0.563; p = 0.036).

Conclusions

FB and RB bearing designs showed similar objective gait recovery trajectories and PROM improvements through 24 months after primary TKA, suggesting no intermediate-term functional advantage from bearing design.