The Importance of Tear Edge Fixation in Modified Transosseous-Equivalent Rotator Cuff Repair: A Biomechanical Study.

PURPOSE: The purpose of this study was to evaluate the impact of dog ear fixation with peripheral sutures on the biomechanical properties of transosseous-equivalent rotator cuff repair.

METHODS: Eight matched-pairs of fresh-frozen cadaveric shoulders were dissected to create an isolated, full thickness supraspinatus tear. One shoulder in each matched pair was randomly selected for repair with a standard transosseous-equivalent suture-bridge technique (TOE), and the contralateral shoulder underwent TOE repair with additional tear edge fixation (TEF). Unidirectional tensile testing was conducted to determine cyclic displacement, linear stiffness, yield load, ultimate load, and mode of failure for each specimen.

RESULTS: The ultimate load and yield load were significantly higher for the TEF group (460 ± 104 N and 455 ± 97 N) than the TOE group (409 ± 111 N and 356 ± 143 N) (p = 0.020, p = 0.019, respectively). No statistical difference was noted in stiffness or displacement. Seven of eight TOE specimens versus two of eight TEF specimens failed by medial row tendon rupture, while one of eight TOE specimens versus five of eight TEF specimens failed by lateral row anchor pullout.

CONCLUSIONS: The addition of peripheral tear edge fixation to transosseous-equivalent rotator cuff repair improves the initial load to failure properties of the construct. However, dog ear fixation has no significant impact on cyclical displacement or stiffness.

CLINICAL RELEVANCE: Tear edge fixation with peripheral sutures should be considered to increase the initial strength of transosseous-equivalent rotator cuff repair while restoring the anatomic footprint. The addition of dog ear fixation may promote healing and minimize the risk of construct failure during the immediate postoperative period.