Design and Evaluation of Partial Weight-Bearing Sensor and Haptic Feedback System for Lower-Extremity Orthopedic Patients

The design of a partial weight-bearing compliance aid for orthopedic surgery patients is presented in this paper. This device is capable of detecting weight-bearing loads and delivers appropriate vibrotactile haptic stimuli to the user to encourage compliance with partial weight-bearing orders. This is achieved with either haptic confirmations of correct weight-bearing loads or haptic alerts when loads exceed a prescribed limit. In a preliminary evaluation with 9 healthy subjects, it was demonstrated that the device has a dynamic sensing accuracy of ±2.43kg (±5.34 lbs.) within the 2.3-23kg (5-50 lb.) weight-bearing range, which is within the clinical tolerance for partial weight bearing. Additionally, a user wearing this device was able to detect the haptic stimuli and discern whether he was exceeding the weight-bearing load. Ultimately the goal is to create a low-cost alternative to existing products seeking to improve patient weight-bearing compliance, with viability as a take-home rehabilitation aid.