Smartphone-Based Goniometry Accuracy in Clinical Scenarios.

This study compared two popular iPhone-based goniometer applications to the gold standard universal goniometer for the measurement of the hip and knee joints in scenarios mimicking the normal pace of an orthopaedic clinical practice.Three physicians measured hip and knee joint angles 35 times with one of three goniometers: universal 12-inch goniometer, DrGoniometer (iPhone-5 based), and SimpleGoniometer (iPhone-5 based). Data wwere analyzed using Pearson correlation coefficient calculations. Average knee angles measured with the universal goniometer, DrGoniometer, and SimpleGoniometer measured 83.46°, 85.23°, and 80.39°, respectively. The smartphone-based goniometers had moderate agreement with the universal goniometer in the knee (r > .322). Average hip angles measured with the universal goniometer, DrGoniometer, and SimpleGoniometer measured 62.34°, 60.87°, and 59.34°, respectively. The smartphone-based goniometers had moderate agreement with the universal goniometer in the hip (r > .168). Smartphone-based goniometers gave accurate, with weak to moderate correlation, measurements for the knee and hip. (Journal of Surgical Orthopaedic Advances 26(4):223-226, 2017).