Altered neural control of gait and its association with pain and joint impairment in adults with haemophilic arthropathy: Clinical and methodological implications

Introduction: It is unknown whether altered neural control is associated with clinical outcomes in people with haemophilic arthropathy (PWHA). The dynamic motor control index during walking (Walk-DMC) is a summary metric of neural control. Aims: The primary aim of this study was to apply the Walk-DMC to assess if people diagnosed with haemophilic arthropathy have impaired neural control of gait and investigate the association of Walk-DMC with pain and joint impairment. Method: The Walk-DMC was assessed using surface electromyography in 11 leg muscles. Twenty-two PWHA and 15 healthy subjects walked on a 30-m walkway at 1 m/s. In addition, pain (visual analogue scale), knee flexion contracture (degrees) and joint impairment (Haemophilia Joint Health Score, HJHS) were assessed. The clinical outcomes were correlated with the Walk-DMC. Multiple regression analysis was performed to predict the Walk-DMC using the clinical outcomes. Results: In 13 PWHA the Walk-DMC was beyond the normal range (80–120 pts). PWHA with an altered Walk-DMC showed more years with arthropathy, more pain, higher knee flexion contracture and a higher HJHS score (P <.05, effect size >.8). Significant negative moderate associations between Walk-DMC and pain, knee flexion contracture and HJHS were found (P <.05). The model that best predicted the Walk-DMC was the pain with knee flexion contracture (R2=.44; P =.004). Conclusions: PWHA with abnormal neural control of gait also has more years with arthropathy, more pain, and more impaired joints. Our results indicate an association between the Walk-DMC index and joint damage, specifically with pain in combination with knee flexion contracture.