Relationship between hip contact force during gait and patient-reported outcome measures 6 months after total hip arthroplasty

Purpose: Evaluating the hip contact force (HCF) during gait is important for assessing treatment outcomes after total hip arthroplasty (THA). This study investigated the relationship between patient-reported outcome measures (PROMs) and HCF during gait after THA as well as gait biomechanical factors affecting HCF during gait in relation to PROMs. Methods: In total, 29 female patients who underwent THA with a 6-month follow-up were included in this study. Musculoskeletal model analysis was performed to obtain the first and second peak values of the HCF during gait and the minimum value between both peaks. PROMs were evaluated using the Japanese Orthopaedic Association Hip Disease Evaluation Questionnaire (JHEQ). The relationship between JHEQ and selected HCFs and between the HCF and gait biomechanical factors was examined. Results: The second peak value of HCF was positively related to the total JHEQ, movement, and mental health scores (r ​= ​−0.551, 0.410, and 0.495, respectively). A positive relationship was found between the second peak value of the HCF and hip flexion–extension range of motion (r ​= ​0.518), maximum hip abduction moment (r ​= ​0.432), and maximum knee extension moment (r ​= ​0.417). A negative relationship was found between the second peak value of the HCF and the maximum knee abduction moment (r ​= ​−0.458). Conclusions: The second peak value of HCF during gait after THA was related to PROMs. The second peak value was related to the hip flexion–extension range of motion, maximum hip abduction moment, and maximum knee extension and abduction moment.