Giovanni Di Giacomo1, Paolo Scarso2, Andrea De Vita2, Mario A Rojas Beccaglia3, Nicole Pouliart4, Nicola de Gasperis2. 1. Department of Orthopaedic Surgery, Concordia Hospital for "Special Surgery", Via delle Sette Chiese 90, 00145, Rome, Italy. concordia@iol.it. 2. Department of Orthopaedic Surgery, Concordia Hospital for "Special Surgery", Via delle Sette Chiese 90, 00145, Rome, Italy. 3. Department of Radiology, Universita' di Roma "La Sapienza", Rome, Italy. 4. Department of Orthopaedic Surgery, Universitair Ziekenhuis, Vrije Universiteit Brussel, Laarbeeklaan 101, 1090, Brussels, Belgium.
Abstract
PURPOSE: The Latarjet procedure is frequently performed when treating traumatic anteroinferior shoulder instability. This procedure is supposed to have a triple effect: osseous, muscular and ligamentous. The main stabilizing mechanism in cadaver studies on fresh-frozen shoulders seems to be the sling effect produced by the subscapularis and the conjoint tendon. It has been hypothesized that muscle contraction in ABER position (abduction-external rotation) is able to translate the humeral head posteriorly and superiorly due to the sling effect. The aim of this study was to analyse the humeral head translation relative to the glenoid with the arm in ABER position with and without muscle contraction. METHODS: Twenty-one subjects divided into two groups (Group A: after Latarjet; Group B: healthy subjects) were examined with an open MRI system with the shoulder in abduction-external rotation (ABER) position to analyse humeral head translation during muscle activity. RESULTS: In normal shoulders, there was no significant difference in anteroposterior or superoinferior translation between the rest position and the muscle-activated state. In subjects after the Latarjet procedure, the difference was significant and was also significant between both groups of subjects for posterior translation, but not for superior translation. CONCLUSION: In patients treated with Latarjet procedure, there are significant changes in glenohumeral translation during muscular activity when in ABER position, with the humeral head going more posteriorly, in comparison with normal shoulders. This study confirms the stabilizing sling effect of the transposed conjoint tendon in the ABER position. LEVEL OF EVIDENCE: Retrospective case-control study, Level III.
PURPOSE: The Latarjet procedure is frequently performed when treating traumatic anteroinferior shoulder instability. This procedure is supposed to have a triple effect: osseous, muscular and ligamentous. The main stabilizing mechanism in cadaver studies on fresh-frozen shoulders seems to be the sling effect produced by the subscapularis and the conjoint tendon. It has been hypothesized that muscle contraction in ABER position (abduction-external rotation) is able to translate the humeral head posteriorly and superiorly due to the sling effect. The aim of this study was to analyse the humeral head translation relative to the glenoid with the arm in ABER position with and without muscle contraction. METHODS: Twenty-one subjects divided into two groups (Group A: after Latarjet; Group B: healthy subjects) were examined with an open MRI system with the shoulder in abduction-external rotation (ABER) position to analyse humeral head translation during muscle activity. RESULTS: In normal shoulders, there was no significant difference in anteroposterior or superoinferior translation between the rest position and the muscle-activated state. In subjects after the Latarjet procedure, the difference was significant and was also significant between both groups of subjects for posterior translation, but not for superior translation. CONCLUSION: In patients treated with Latarjet procedure, there are significant changes in glenohumeral translation during muscular activity when in ABER position, with the humeral head going more posteriorly, in comparison with normal shoulders. This study confirms the stabilizing sling effect of the transposed conjoint tendon in the ABER position. LEVEL OF EVIDENCE: Retrospective case-control study, Level III.
Authors: Joshua W Giles; Harm W Boons; Ilia Elkinson; Kenneth J Faber; Louis M Ferreira; James A Johnson; George S Athwal Journal: J Shoulder Elbow Surg Date: 2012-09-28 Impact factor: 3.019
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Authors: Nobuyuki Yamamoto; Takayuki Muraki; Kai-Nan An; John W Sperling; Robert H Cofield; Eiji Itoi; Gilles Walch; Scott P Steinmann Journal: J Bone Joint Surg Am Date: 2013-08-07 Impact factor: 5.284
Authors: Giovanni Di Giacomo; Alberto Costantini; Nicola de Gasperis; Andrea De Vita; Bernard K H Lin; Marco Francone; Mario A Rojas Beccaglia; Marco Mastantuono Journal: Int J Shoulder Surg Date: 2013-01