The effect of infraspinatus disruption on glenohumeral torque and superior migration of the humeral head: A biomechanical study

Nariyuki Mura, Shawn W. O'Driscoll, Mark E. Zobitz, Guido Heers, Thomas R. Jenkyn, Siaw Meng Chou, Andreas M. Halder, Kai Nan An

Research output: Contribution to journalArticle

51 Scopus citations

Abstract

Rotator cuff ruptures that extend into the infraspinatus tendon may cause dysfunction and superior migration of the humerus. The purpose of this study was to determine whether a threshold size of infraspinatus defect exists beyond which abduction torque generation decreases and superior migration of the humeral head increases. Glenohumeral abduction torque and superior humeral head translations were measured in hanging arms in neutral rotation in cadaver shoulders (n = 10). Loads were applied to the rotator cuff tendons and the middle deltoid. After sequential detachment of the infraspinatus, abduction torque progressively decreased. At three-fifths detachment, abduction torque was significantly lower than after supraspinatus release alone (52% vs 61%, P < .05). Superior translation after complete supraspinatus and infraspinatus detachment increased significantly (P < .05), but no intermediate threshold was detected. Therefore, the entire infraspinatus contributes to abduction torque generation and stabilizes the humeral head against superior subluxation. Even with a tear extending into the superior infraspinatus, the infraspinatus contributes abduction force generation across the glenohumeral joint.

Original languageEnglish (US)
Pages (from-to)179-184
Number of pages6
JournalJournal of Shoulder and Elbow Surgery
Volume12
Issue number2
DOIs
StatePublished - Mar 2003

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ASJC Scopus subject areas

  • Surgery
  • Orthopedics and Sports Medicine

Cite this

Mura, N., O'Driscoll, S. W., Zobitz, M. E., Heers, G., Jenkyn, T. R., Chou, S. M., Halder, A. M., & An, K. N. (2003). The effect of infraspinatus disruption on glenohumeral torque and superior migration of the humeral head: A biomechanical study. Journal of Shoulder and Elbow Surgery, 12(2), 179-184. https://doi.org/10.1067/mse.2003.9