Impact of a simulated DIPJ Arthrodesis on Movement and Force Patterns

Abstract

Distal interphalangeal joint (DIPJ) arthrodesis is a well-proven therapy for osteoarthritis in the DIPJ. Since the upper limb is effectively a linked chain which is moved by interlinked, joint-overlapping muscle-tendon units, impacts on movement and force patterns are expected to occur in response to arthrodesis. In this context, a real-time quantitative analysis has not been performed to date. Finger motion and force development during grasping were dynamically measured and quantitatively analyzed in 19 healthy volunteers with a simulated DIPJ arthrodesis using a TUB (Technische Universität Berlin) sensor glove during fist closure and evaluating two types of force grips compared with the physiological grip. Typical motion patterns were found. During physiological fist closure, the average flexion angle was 71.5° in the metacarpophalangeal joint (MPJ), 76.8° in the proximal interphalangeal joint (PIPJ) and 37.3° in the distal interphalangeal joint (DIPJ). With DIPJ arthrodesis, the flexion angle decreased to 49.6° in the PIPJ, whereas it increased slightly to 77.3° in the MPJ. During force grip I, the average physiological flexion angles were 18.3° in the MPJ, 39.6° in the PIPJ and 42.6° in the DIPJ. With simulated DIPJ arthrodesis, the flexion angle in the MPJ increased to 28.4°, whereas it decreased to 25.2° in the PIPJ. Force grip II yielded physiological flexion angles of 30.9° in the MPJ, 36.6° in the PIPJ and 29.0° in the DIPJ. In response to simulated DIPJ arthrodesis, the angle in the MPJ increased to 34.4° while it decreased to 23.3° in the PIPJ. The forces measured with force grips were almost equally distributed under physiological conditions. In response to simulated DIPJ arthrodesis, the average decrease in the measured force of a finger was no more than 1.4%. This study was the first to introduce a quantitative analysis of grasping with simulated DIPJ arthrodesis. Based on this analysis, the study demonstrates the dynamic interaction of the finger joints as well as force patterns on the individual finger rays of the hand in real-time.