Association between Kinematic Patterns and Patient-Reported Outcome Measures in Revision Total Knee Arthroplasty.

INTRODUCTION: While knee kinematics are well-documented in primary TKA, less is understood regarding revision TKA (rTKA), where altered soft tissue conditions may influence kinematics. This study aimed to investigate the relationship between kinematic parameters, specifically anteroposterior (AP) translation and post-cam engagement, and patient-reported outcome measures (PROMs) in rTKA patients. MATERIALS AND METHODS: Thirty patients who underwent rTKA between 2022 and 2024 were assessed at a minimum six-month follow-up. Tibiofemoral kinematics, measured as femoral AP translation relative to the tibia, were evaluated during open-chain flexion-extension (FE) and closed-chain exercises (sit-to-stand (STS) and a lunge) using fluoroscopy. Two clusters, categorized by higher and lower PROMs, were compared for AP translation and post-cam engagement. RESULTS: In the medial compartment, the low-PROMs group exhibited a more anterior femoral position compared to the high-PROMs group, with statistical significance observed during mid-flexion of the STS (50.87% (SD, 4.04) vs. 47.57% (SD, 2.75); p = 0.043) and FE exercise (51.97% (SD, 3.83) vs. 48.55% (SD, 3.62); p = 0.037). No significant differences were found in the lateral compartment. Post-cam engagement did not differ between the groups in either open- or closed-chain exercises. CONCLUSIONS: Poorer PROM scores were associated with a more anterior femoral position in the medial compartment during mid-flexion of STS and FE exercises. Further research is needed to explore the relationship between kinematic variations and PROMs in rTKA patients.