Repair of rotator cuff injuries using different composites.

Aim: Rotator cuff repairs have shown a high level of re-ruptures. It is hypothesised that the use of rhBMP-2 in a carrier could improve the biomechanical and histological properties of the repair.

Material And Methods: Controlled experimental study conducted on 40 rats with section and repair of the supraspinatus tendon and randomisation to one of five groups: Group 1 (control) only suture; Group 2 (double control), suture and alginate-chitin carrier; Group 3 (alginate-control), the rhBMP-2 was added to the alginate; Group 4 (chitin-control) application of the rhBMP-2 to the chitin, and Group 5 (double sample): The two components of the carrier (alginate and chitin) have rhBMP-2. A biomechanical and histological analysis was performed at 4 weeks.

Results: A gap was observed in all cases 4 weeks after supraspinatus detachment. The re-rupture rate was 7.5%, with 20% of them in the control-alginate Group. Histologically the best results were obtained in the double sample group: 4.5 (3.3-5.0). Double sample were also able to support higher loads to failure: 62.9N (59.8 to 69.4) with lower rigidity 12.7 (9.7 to 15.9).

Conclusions: The use of alginate-chitin carrier with rhBMP-2 improves the biomechanical and histological properties of the repair site in a chronic rotator cuff tear.