Robert J Hillen1, Bart Bolsterlee2, Dirkjan H E J Veeger3. 1. Waterland Ziekenhuis Purmerend, Waterlandlaan 250, 1441 RN Purmerend, The Netherlands. Electronic address: hillen_rj@hotmail.com. 2. Neuroscience Research Australia Margarete Ainsworth Building, Barker St Randwick, NSW 2031, Australia. 3. Faculty Mechanical, Maritime and Materials Engineering, Department of Biomechanical Engineering, Delft University of Technology, Delft, The Netherlands; Department of Human Movement Sciences, Research institute MOVE, Vrije Universiteit Amsterdam, The Netherlands.
Abstract
BACKGROUND: Malunion of the clavicle with shortening after mid shaft fractures can give rise to long-term residual complaints. The cause of these complaints is as yet unclear. METHODS: In this study we analysed data of an earlier experimental cadaveric study on changes of shoulder biomechanics with progressive shortening of the clavicle. The data was used in a musculoskeletal computer model to examine the effect of clavicle shortening on muscle function, expressed as maximal muscle moments for abduction and internal rotation. FINDINGS: Clavicle shortening results in changes of maximal muscle moments around the shoulder girdle. The mean values at 3.6cm of shortening of maximal muscle moment changes are 16% decreased around the sterno-clavicular joint decreased for both ab- and adduction, 37% increased around the acromion-clavicular joint for adduction and 32% decrease for internal rotation around the gleno-humeral joint in resting position. INTERPRETATION: Shortening of the clavicle affects muscle function in the shoulder in a computer model. This may explain for the residual complaints after short malunion with shortening. LEVEL OF EVIDENCE: Basic Science Study. Biomechanics. Cadaveric data and computer model.
BACKGROUND: Malunion of the clavicle with shortening after mid shaft fractures can give rise to long-term residual complaints. The cause of these complaints is as yet unclear. METHODS: In this study we analysed data of an earlier experimental cadaveric study on changes of shoulder biomechanics with progressive shortening of the clavicle. The data was used in a musculoskeletal computer model to examine the effect of clavicle shortening on muscle function, expressed as maximal muscle moments for abduction and internal rotation. FINDINGS: Clavicle shortening results in changes of maximal muscle moments around the shoulder girdle. The mean values at 3.6cm of shortening of maximal muscle moment changes are 16% decreased around the sterno-clavicular joint decreased for both ab- and adduction, 37% increased around the acromion-clavicular joint for adduction and 32% decrease for internal rotation around the gleno-humeral joint in resting position. INTERPRETATION: Shortening of the clavicle affects muscle function in the shoulder in a computer model. This may explain for the residual complaints after short malunion with shortening. LEVEL OF EVIDENCE: Basic Science Study. Biomechanics. Cadaveric data and computer model.
Authors: Philippe P De Rooij; Esther M M Van Lieshout; Ivo J Schurink; Michael H J Verhofstad Journal: Eur J Trauma Emerg Surg Date: 2020-06-13 Impact factor: 3.693