An analysis of wrist and forearm range of motion using the Dartfish motion analysis system.

STUDY DESIGN: Clinical measurement. INTRODUCTION: Wrist range of motion (ROM) is considered the universal measurement of success for both surgical and non-surgical treatments. A goniometer can be challenging for an individual to use by themselves, whereas the Dartfish app can analyze and provide immediate feedback to monitor and evaluate patients' kinematic changes during recovery after injury. PURPOSE OF STUDY: To establish the validity and reliability of the Dartfish app measuring ROM to be used in clinical applications. METHODS: Twelve healthy participants, (18-25 yrs) , with no previous history of wrist injuries, were recruited for this study. Flexion/extension, radial/ulnar deviation, and supination/pronation range of motion measures were collected using a goniometer (two-arm) and Dartfish video analysis. Statistical analyses, such as t-tests and the Pearson correlation coefficient, as well as reliability analyses, such as intraclass correlation coefficient (ICC) and Bland-Altman plots, were performed. RESULTS: There was no significant difference between the goniometer and Dartfish ROM measurements except for ulnar deviation. The concurrent validity showed nearly perfect correlations between examiners using Dartfish with r-values in the range 0.90-0.99, and between examiner2 and the goniometer showed medium, large, and very large correlations since the values were in the range 0.418-0.829. The ICC for test-retest reliability had an excellent agreement that ranged from 0.993-0.999, and the ICC values for inter-observer reliability had good and excellent agreement, which were in the range 0.893-0.997. CONCLUSION: Overall, the results demonstrated that the Dartfish app was a reliable and valid method to measure wrist and forearm ROM. A patient would be able to easily record their own ROM measurement videos and track their progress during their recovery without the need of their physician to track their progress.

Utility of an image-based technique to detect changes in joint congruency following simulated joint injury and repair: an in vitro study of the elbow.

BACKGROUND: Investigating joint mechanics is important when determining the etiology of osteoarthritis, as degenerative changes are thought to occur due to altered joint mechanics. The objective of this study was to demonstrate the utility of an x-ray computed tomography-based approach to evaluate joint congruency in the setting of subtle kinematic alterations, employing an in vitro model of collateral ligament repair of the elbow. METHODS: Active and passive elbow flexion was performed in 4 and 5 fresh-frozen cadaveric upper extremities respectively using an elbow motion simulator in the valgus gravity dependent positions. The collateral ligaments were sectioned and repaired. A registration and inter-bone distance algorithm were then used to examine ulnohumeral joint congruency (quantified as surface area) throughout elbow flexion. Valgus angulation was also measured. FINDINGS: Following ligament sectioning and repair, there was a 1.2±1.0° increase in valgus angulation in active flexion and a 21.2±26.2% decrease in surface area. In passive flexion, valgus angulation increased 3.3±2.2° and surface area decreased 57.9±39.9%. INTERPRETATION: The technique described to quantify joint congruency proved to be sensitive enough to detect large changes in joint surface interactions inspite of only small changes in traditionally measured kinematics. These changes in joint congruency may, in part, explain the high incidence of arthritis that has been reported following ligament injuries of the elbow, even in the absence of clinically detectable instability. This technique, when adapted for in vivo use, will be a useful tool to evaluate joint function and the effectiveness of treatments non-invasively.