47. Development of a Wireless, Wearable Goniometer for Hand Physiotherapy Biofeedback

PURPOSE: Hand physiotherapy after surgery has been shown to accelerate recovery of joint range of motion (ROM). Our group has designed a wireless, wearable goniometer to allow patients to independently and continuously measure the angle of their proximal interphalangeal (PIP) joint during home therapy exercises. Research has demonstrated that biofeedback during physiotherapy is effective, engaging, and can lead to improved outcomes. Our hope is that the ability to see real-time feedback of joint position during therapy will encourage patients to work harder, complete more exercises, and get the most benefit from their therapy programs. The purpose of this study was to assess the accuracy and feasibility for the use of this novel device during hand physiotherapy. METHODS: Volunteers were fitted with the wearable device about their right PIPJ, which was then actively flexed and extended through its complete range of motion under live fluoroscopy (lateral projection). Paired angular measurements were derived from the wearable device and fluoroscopic images, and this was then repeated for the left PIPJ. Separately, patients donned the wearable device and were guided through four to five positions of progressive flexion. Paired angular measurements were derived from the wearable device and a handheld goniometer operated by a certified hand therapist (CHT). Next, volunteers were guided through a simulated home exercise program (HEP) (composite fist, PIP blocking, blocked extension) by a CHT while the device measured PIPJ angle in real time. The bilateral index, middle, and small fingers were tested in each subject. Bland-Altman plots were used to visualize correspondence between the device measurement and the fluoroscopic or handheld goniometer measurements. Means were compared using a paired t-test. RESULTS: Six volunteers (12 fingers, 259 paired data points) were included in the fluoroscopy portion of the study. Mean difference between device and fluoroscopic measurement was 0.9o (SD = 2.2o, 95% CI = 0.7o - 1.2o), with errors ranging from -4.7o to +5.6o. Nine volunteers (27 fingers, 212 paired data-points) were included in the handheld goniometer portion of the study. Mean difference between device and handheld goniometer measurement was 0.6o (SD = 5.2o, 95% CI = -0.1o - 1.3o), with errors ranging from -13.1o to 12.9o. The device successfully tracked PIPJ angle in real time during a simulated HEP for all fingers tested. CONCLUSION: The wearable goniometer device is acceptably precise and accurate. It can track PIPJ angle during a simulated HEP and is a feasible method of providing biofeedback.