BACKGROUND: Malunion after mid shaft clavicle fractures has recently been recognized as a cause of pain and dysfunction of the shoulder. The mechanism that causes these complaints is however yet unclear. In this study we describe the kinematic changes that occur in the shoulder girdle due to clavicle shortening. METHODS: An experimental cadaveric study was performed on five shoulders of three fresh frozen specimens. The specimens were fixed in an upright position that allowed free motion of the shoulder girdle. We measured position of the bony structures with an opto-electronic system (Northern Digital Inc., Waterloo, Ontario Canada) in rest and during in a series of motions. Measurements were done with a normal clavicle and after shortening of the clavicle by 1.2, 2.4 and 3.6 cm. The shoulders were moved manually by one of the researchers. We examined for changes in resting position and during movement that resulted from the experimental shortening of the clavicle. FINDINGS: In the resting position, winging of the scapula increased with resultant changes in the orientation of the glenoid, acromio-clavicular and sterno-clavicular joints and an altered position of the clavicle. On average protraction increased by 20°, lateral rotation changed 12° and posterior tilt decreased by 7°. Clavicle shortening affected sterno-clavicular joint rotations but did not do so in the acromio-clavicular joint. In arm elevation the offset in scapula orientation at resting position stayed relatively constant over the full range of motion but the amount of disposition is progressive in relation to the amount of shortening. INTERPRETATION: Shortening of the clavicle leads to significant changes in the shoulder girdle in resting position and in movement.
BACKGROUND: Malunion after mid shaft clavicle fractures has recently been recognized as a cause of pain and dysfunction of the shoulder. The mechanism that causes these complaints is however yet unclear. In this study we describe the kinematic changes that occur in the shoulder girdle due to clavicle shortening. METHODS: An experimental cadaveric study was performed on five shoulders of three fresh frozen specimens. The specimens were fixed in an upright position that allowed free motion of the shoulder girdle. We measured position of the bony structures with an opto-electronic system (Northern Digital Inc., Waterloo, Ontario Canada) in rest and during in a series of motions. Measurements were done with a normal clavicle and after shortening of the clavicle by 1.2, 2.4 and 3.6 cm. The shoulders were moved manually by one of the researchers. We examined for changes in resting position and during movement that resulted from the experimental shortening of the clavicle. FINDINGS: In the resting position, winging of the scapula increased with resultant changes in the orientation of the glenoid, acromio-clavicular and sterno-clavicular joints and an altered position of the clavicle. On average protraction increased by 20°, lateral rotation changed 12° and posterior tilt decreased by 7°. Clavicle shortening affected sterno-clavicular joint rotations but did not do so in the acromio-clavicular joint. In arm elevation the offset in scapula orientation at resting position stayed relatively constant over the full range of motion but the amount of disposition is progressive in relation to the amount of shortening. INTERPRETATION: Shortening of the clavicle leads to significant changes in the shoulder girdle in resting position and in movement.
Authors: T David Luo; Ali Ashraf; A Noelle Larson; Anthony A Stans; William J Shaughnessy; Amy L McIntosh Journal: Orthopedics Date: 2015-04 Impact factor: 1.390
Authors: Sylvia A Stegeman; Pieter Bas de Witte; Sjoerd Boonstra; Jurriaan H de Groot; Jochem Nagels; Pieta Krijnen; Inger B Schipper Journal: Acta Orthop Date: 2015 Impact factor: 3.717
Authors: Claudio Rosso; Michael Nasr; Kempland C Walley; Ethan R Harlow; Babak Haghpanah; Ashkan Vaziri; Arun J Ramappa; Ara Nazarian; Joseph P DeAngelis Journal: PLoS One Date: 2017-01-06 Impact factor: 3.240