Rotator Cuff Repair Augmentation in a Canine Model with Use of a Woven Poly-L-Lactide Device

• Published in: Journal of bone and joint surgery. American volume 2009-05, Vol.91 (5), p.1159-1171
• Main Authors: Derwin, Kathleen A, Codsi, Michael J, Milks, Ryan A, Baker, Andrew R, McCarron, Jesse A, Iannotti, Joseph P
• Format: Article
• Language: English
• Subjects: Animals; Biocompatible Materials; Biological and medical sciences; Biomechanical Phenomena; Cadaver; Dioxanes - therapeutic use; Diseases of the osteoarticular system; Dogs; Juxtaarticular diseases. Extraarticular rhumatism; Male; Medical sciences; Orthopedic surgery; Rotator Cuff - physiology; Rotator Cuff - surgery; Scientific; Surgery (general aspects). Transplantations, organ and tissue grafts. Graft diseases; Tissue Scaffolds; Wound Healing
• ISSN: 0021-9355; 1535-1386
• DOI: 10.2106/JBJS.H.00775

BackgroundDespite advances in surgical treatment options, failure rates of rotator cuff repair have continued to range from 20% to 90%. Hence, there is a need for new repair strategies that provide effective mechanical reinforcement of rotator cuff repair as well as stimulate and enhance the intrinsic healing potential of the patient. The purpose of this study was to evaluate the extent to which augmentation of acute repair of rotator cuff tendons with a newly designed poly-L-lactide repair device would improve functional and biomechanical outcomes in a canine model.MethodsEight adult, male mongrel dogs (25 to 30 kg) underwent bilateral shoulder surgery. One shoulder underwent tendon release and repair only, and the other was subjected to release and repair followed by augmentation with the repair device. At twelve weeks, tendon retraction, cross-sectional area, stiffness, and ultimate load of the repair site were measured. Augmented repairs underwent histologic assessment of biocompatibility. In addition, eight pairs of canine cadaver shoulders underwent infraspinatus injury and repair with and without device augmentation with use of identical surgical procedures and served as time-zero biomechanical controls. Eight unpaired, canine cadaver shoulders were included as normal biomechanical controls.ResultsAt time zero, repair augmentation significantly increased the ultimate load (23%) (p = 0.034) but not the stiffness of the canine infraspinatus tendon repair. At twelve weeks, the poly-L-lactide scaffold was observed to be histologically biocompatible, and augmented repairs demonstrated significantly less tendon retraction (p = 0.008) and significantly greater cross-sectional area (137%), stiffness (26%), and ultimate load (35%) than did repairs that had not been augmented (p < 0.001, p = 0.002, and p = 0.009, respectively).ConclusionsWhile limiting but not eliminating tendon repair retraction, the augmentation device provided a tendon-bone bridge and scaffold for host tissue deposition and ingrowth, resulting in improved biomechanical function of the repair at twelve weeks.Clinical RelevanceThe augmentation device, applied in a similar manner as described in the present study, might offer a functional benefit to patients undergoing rotator cuff repair.