DooSup Kim1, DongWoo Lee2, YoungHwan Jang2, JunSeop Yeom2, Scott A Banks3. 1. Department of Orthopedic Surgery, Wonju College of Medicine, Yonsei University, Wonju Severance Christian Hospital, Gangwon, Republic of Korea; Department of Mechanical and Aerospace Engineering, University of Florida, Gainesville, FL, USA. 2. Department of Orthopedic Surgery, Wonju College of Medicine, Yonsei University, Wonju Severance Christian Hospital, Gangwon, Republic of Korea. 3. Department of Mechanical and Aerospace Engineering, University of Florida, Gainesville, FL, USA. Electronic address: scottabanks1@gmail.com.
Abstract
BACKGROUND: Short malunion of the clavicle after fracture can change scapular kinematics and alter clinical outcome. However, the effects of malunion on kinematics and outcomes remains poorly understood because there have been no in vivo studies measuring changes during active motion with malunion. This study aimed to measure and to compare in vivo 3-dimensional (3D) scapular kinematics between normal shoulders and shoulders with short malunion using 3D-2-dimensional model image registration techniques. METHODS: Fifteen patients with clavicle fracture who had been treated conservatively were enrolled in this study. In these patients, the angle of scapular upward rotation, posterior tilting, and external rotation were compared between shoulders with short malunion and contralateral, normal shoulders. A 3D-2-dimensional model image registration technique was used to determine the 3D orientation of the scapula. RESULTS: Scapular upward rotation increased following increase of the arm elevation angle and also showed a significant difference by arm elevation in both groups (P = .04). Posterior tilting of the scapula gradually increased as the arm abduction angle increased, and this varied significantly between groups (P = .01). Shoulders with short malunion also showed a more internally rotated position than the contralateral, normal shoulders between 100° and the maximum abduction angle (P = .04). CONCLUSION: Our results suggest that clavicle shortening of >10% greatly affects scapular kinematics in vivo. Further studies will be needed to determine the clinical implications of short malunion of the clavicle.
BACKGROUND: Short malunion of the clavicle after fracture can change scapular kinematics and alter clinical outcome. However, the effects of malunion on kinematics and outcomes remains poorly understood because there have been no in vivo studies measuring changes during active motion with malunion. This study aimed to measure and to compare in vivo 3-dimensional (3D) scapular kinematics between normal shoulders and shoulders with short malunion using 3D-2-dimensional model image registration techniques. METHODS: Fifteen patients with clavicle fracture who had been treated conservatively were enrolled in this study. In these patients, the angle of scapular upward rotation, posterior tilting, and external rotation were compared between shoulders with short malunion and contralateral, normal shoulders. A 3D-2-dimensional model image registration technique was used to determine the 3D orientation of the scapula. RESULTS: Scapular upward rotation increased following increase of the arm elevation angle and also showed a significant difference by arm elevation in both groups (P = .04). Posterior tilting of the scapula gradually increased as the arm abduction angle increased, and this varied significantly between groups (P = .01). Shoulders with short malunion also showed a more internally rotated position than the contralateral, normal shoulders between 100° and the maximum abduction angle (P = .04). CONCLUSION: Our results suggest that clavicle shortening of >10% greatly affects scapular kinematics in vivo. Further studies will be needed to determine the clinical implications of short malunion of the clavicle.
Authors: Umile Giuseppe Longo; Laura Risi Ambrogioni; Alessandra Berton; Vincenzo Candela; Carlo Massaroni; Arianna Carnevale; Giovanna Stelitano; Emiliano Schena; Ara Nazarian; Joseph DeAngelis; Vincenzo Denaro Journal: Int J Environ Res Public Health Date: 2020-04-24 Impact factor: 3.390