BACKGROUND: Rotator cuff tears are common and not well-understood shoulder problems. Structural and mechanical inhomogeneity of the supraspinatus tendon complicates accurate prediction of risk of tear propagation and may affect appropriate clinical treatment. HYPOTHESIS: We propose that interactions between the supraspinatus and infraspinatus tendons are critical to load bearing at the glenohumeral joint and warrant investigation. STUDY DESIGN: Controlled laboratory study. METHODS: Principal strains in the infraspinatus tendon of cadaveric human shoulders were evaluated with increasing anterior full-thickness supraspinatus tendon tear sizes and loading to evaluate whether a mechanical interaction between the supraspinatus and infraspinatus tendons exists. A constant nominal load was attached to the infraspinatus throughout all experimental conditions. RESULTS: Increasing supraspinatus tendon tear width from intact and 33% to 66% and increasing supraspinatus tendon load caused an increase in maximum and a decrease in minimum principal strain in the infraspinatus tendon. Increasing the supraspinatus tendon tear size from intact to 33% of the width had no significant effect on infraspinatus tendon strain. CONCLUSION: Supraspinatus and infraspinatus tendons mechanically interact. The observed significant increase in maximum and decrease in minimum principal strain was concurrent in both the infraspinatus and supraspinatus tendons. CLINICAL RELEVANCE: Changes in infraspinatus tendon strain associated with increases in supraspinatus tendon tear size and loading may shield a torn supraspinatus tendon from further injury or may have an effect on the load-bearing capacity of the infraspinatus tendon. Results also imply that the effect of a small tear that does not compromise the confluent region between the supraspinatus and infraspinatus tendon may be localized, eliminating its effect on infraspinatus tendon strain.
BACKGROUND: Rotator cuff tears are common and not well-understood shoulder problems. Structural and mechanical inhomogeneity of the supraspinatus tendon complicates accurate prediction of risk of tear propagation and may affect appropriate clinical treatment. HYPOTHESIS: We propose that interactions between the supraspinatus and infraspinatus tendons are critical to load bearing at the glenohumeral joint and warrant investigation. STUDY DESIGN: Controlled laboratory study. METHODS: Principal strains in the infraspinatus tendon of cadaveric human shoulders were evaluated with increasing anterior full-thickness supraspinatus tendon tear sizes and loading to evaluate whether a mechanical interaction between the supraspinatus and infraspinatus tendons exists. A constant nominal load was attached to the infraspinatus throughout all experimental conditions. RESULTS: Increasing supraspinatus tendon tear width from intact and 33% to 66% and increasing supraspinatus tendon load caused an increase in maximum and a decrease in minimum principal strain in the infraspinatus tendon. Increasing the supraspinatus tendon tear size from intact to 33% of the width had no significant effect on infraspinatus tendon strain. CONCLUSION: Supraspinatus and infraspinatus tendons mechanically interact. The observed significant increase in maximum and decrease in minimum principal strain was concurrent in both the infraspinatus and supraspinatus tendons. CLINICAL RELEVANCE: Changes in infraspinatus tendon strain associated with increases in supraspinatus tendon tear size and loading may shield a torn supraspinatus tendon from further injury or may have an effect on the load-bearing capacity of the infraspinatus tendon. Results also imply that the effect of a small tear that does not compromise the confluent region between the supraspinatus and infraspinatus tendon may be localized, eliminating its effect on infraspinatus tendon strain.
Authors: Mark J Albritton; Robert D Graham; Richard S Richards; Carl J Basamania Journal: J Shoulder Elbow Surg Date: 2003 Sep-Oct Impact factor: 3.019
Authors: Shivam A Shah; Ioannis Kormpakis; Leonardo Cavinatto; Megan L Killian; Stavros Thomopoulos; Leesa M Galatz Journal: J Orthop Res Date: 2017-06-02 Impact factor: 3.494
Authors: Spencer E Szczesny; John M Peloquin; Daniel H Cortes; Jennifer A Kadlowec; Louis J Soslowsky; Dawn M Elliott Journal: J Biomech Eng Date: 2012-02 Impact factor: 2.097
Authors: Paul E Matuszewski; Yi-Ling Chen; Spencer E Szczesny; Spencer P Lake; Dawn M Elliott; Louis J Soslowsky; George R Dodge Journal: Connect Tissue Res Date: 2012-02-13 Impact factor: 3.417
Authors: Ryan C Locke; John M Peloquin; Elisabeth A Lemmon; Adrianna Szostek; Dawn M Elliott; Megan L Killian Journal: J Biomech Eng Date: 2017-11-01 Impact factor: 2.097