Augmentation of a Rotator Cuff Suture Repair Using rhPDGF-BB and a Type I Bovine Collagen Matrix in an Ovine Model

Background: Rotator cuff tears are a common source of shoulder pain. High rates (20%-94%) of structural failure of the repair have been attributed to multiple factors, including poor repair tissue quality and tendon-to-bone integration. Biologic augmentation using growth factors has potential to promote tendon-to-bone integration, improving the function and long-term success of the repair. One such growth factor is platelet-derived growth factor-BB (PDGF-BB), which has been shown to improve healing in tendon and bone repair models. Hypothesis: Recombinant human PDGF-BB (rhPDGF-BB) combined with a highly porous type I bovine collagen matrix will improve the biomechanical function and morphologic appearance of the repair in a dose-dependent manner, relative to a suture-only control, after 12 weeks in an acute ovine model of rotator cuff repair. Study Design: Controlled laboratory study. Methods: An interpositional graft consisting of rhPDGF-BB and a type I collagen matrix was implanted in an ovine model of rotator cuff repair. Biomechanical and histologic analyses were performed to determine the functional and anatomic characteristics of the repair after 12 weeks. Results: A significant increase in the ultimate load to failure was observed in repairs treated with 75 mu g (1490.5 +/- 224.5 N, P = .029) or 150 mu g (1486.6 +/- 229.0 N, P = .029) of rhPDGF-BB, relative to suture-only controls (910.4 +/- 156.1 N) and the 500-mu g rhPDGF-BB group (677.8 +/- 105.9 N). The 75-mu g and 150-mu g rhPDGF-BB groups also exhibited increased tendon-to-bone interdigitation histologically. No differences in inflammation or cellularity were observed among treatments. Conclusion: This study demonstrated that an interpositional graft consisting of rhPDGF-BB (75 or 150 mg) and a type I collagen matrix was able to improve the biomechanical strength and anatomic appearance in an ovine model of rotator cuff repair compared to a suture-only control and the 500-mg rhPDGF-BB group. Clinical Relevance: Recombinant human PDGF-BB combined with a type I collagen matrix has potential to be used to augment surgical repair of rotator cuff tears, thereby improving clinical success.