How Much Hip Motion Is Used in Real-Life Activities? Assessment of Hip Flexion by a Wearable Sensor and Implications After Total Hip Arthroplasty

Abstract

BackgroundHip range of motion precautions are often considered a requirement for patients after total hip replacement. Few studies have attempted to estimate hip motion during activities of daily living. The purpose of this study is to evaluate hip range of motion and gait during real-life activities in healthy individuals with a novel tracking wearable sensor. MethodsThirty subjects used a hip motion tracking device during a series of tested activities. Healthy volunteers were selected, and subjects were excluded if they reported symptoms in the limb or known deviation in their gait. Hip flexion was evaluated during common activities of daily living. ResultsHip range of motion during walking averaged minimum to maximum hip flexion of 9.9°-49.3°, respectively. During stair ascent, the average flexion arc widened from minimum 19.6° to maximum 67.8° flexion. Stair descent had the most narrow arc of 26.2°-52.4° hip flexion. Squatting averaged 120.0° of hip flexion, with the transition from sitting to standing averaging 103.0°. Getting on and off of the toilet averaged maximum 112.6°, while tying shoes averaged 126.1° maximum hip flexion. ConclusionHip precautions are often enforced after total hip arthroplasty without knowing normal arcs of motion during real-life activities. Knowledge of hip motion during activities of daily living in healthy individuals is useful information in setting goals and in educating total hip arthroplasty patients. This technology can be useful in guiding postoperative precautions and also in monitoring patients after hip replacement with real-time monitoring.