A biomechanical analysis of gap formation and failure mechanics of a xenograft-reinforced rotator cuff repair in a cadaveric model

• Published in: Journal of shoulder and elbow surgery 2012-08, Vol.21 (8), p.1072-1079
• Main Authors: Shea, Kevin P., MD, Obopilwe, Elifho, MS, Sperling, John W., MD, MBA, Iannotti, Joseph P., MD, PhD
• Format: Article
• Language: English
• Subjects: Aged; Biological and medical sciences; biomechanical evaluation; Biomechanical Phenomena; Biomechanics. Biorheology; Cadaver; Diseases of the osteoarticular system; ECM graft; extracellular matrix; Female; Fundamental and applied biological sciences. Psychology; Humans; Male; Medical sciences; Middle Aged; Orthopedics; Reconstructive Surgical Procedures - methods; Rotator Cuff - surgery; rotator cuff reinforcement; Rotator cuff repair; Sensitivity and Specificity; Shoulder Joint - surgery; Stress, Mechanical; Suture Techniques; Tensile Strength; Tissues, organs and organisms biophysics; Transplantation, Heterologous
• ISSN: 1058-2746; 1532-6500
• DOI: 10.1016/j.jse.2011.07.024

Hypothesis Failure rates of rotator cuff repairs are reported to be as high as 90%, in part because of gap formation at the repair site that occurs before healing. The purpose of this study was to evaluate whether the application of an extracellular matrix (ECM) graft (Conexa; Tornier, Edina, MN, USA) to a rotator cuff repair will decrease the gap formation at the tendon-bone interface and increase the ultimate load to failure over control specimens by mechanically sharing load with the repair in a cadaveric model. Methods Six pairs of human cadaveric shoulders were used to test ECM-reinforced and unreinforced rotator cuff repairs for repair-site gapping, ultimate load, failure mode, and load-sharing capabilities of the ECM patch under both cyclic and monotonic loading. Results The gap formation under cyclic loading was reduced by 40% for the reinforced specimens compared with the control group (1.3 ± 0.6 mm vs 2.1 ± 0.5 mm, P < .05) The load at 5-mm gap formation was significantly higher for the reinforced group (389 ± 71 N) compared with the control group (307 ± 33 N) ( P < .05). The ultimate load to failure was significantly higher for the ECM-reinforced group compared with the control group: 429 ± 69 N versus 335 ± 57 N ( P < .05). The ECM graft was estimated to share 35% of the load applied to the tendon repair. Conclusions Application of an ECM graft to a rotator cuff repair decreased tendon gapping and increased load to failure by load sharing in a human rotator cuff repair model.