Does suture depth affect the pull-out strength of supraspinatus repair? A cadaveric model

Abstract

© 2018, Medical Association of Thailand. All rights reserved. Background: The strength of a supraspinatus tendon repair depends on many factors. One factor, the distance from the suture-bite to the lateral edge of the repaired tendon, has never been biomechanically evaluated. Objective: The more medial suture depth to the repaired supraspinatus tendon could obtained the better pull-out strength compared to the lateral suture-depth distance. Materials and Methods: Six paired human supraspinatus tendons were harvested and were randomly assigned to be repaired with Fiberwire® No. 2 at different suture depths (distance from the lateral tendon edge to the suture bite). Biomechanics properties were tested and modes of failure were noted. Results: All characteristics of the tendon specimens were normal. Load to failure was found to be proportional to the suture depth by 19.65 N/mm displacement. A suture depth of 15 mm had the highest load to failure at 275.1±10.5 N(p-value<0.01). The mode of failure in two of the six 15 mm specimens was suture breakage; the remaining four specimens failed at the suture-tendon interface. Conclusion: A suture bite located 15 mm from the lateral tendon edge provides the best possible biomechanical properties with the lowest failure rate. The most common mode offailure is pull-out at the suture-tendon interface.