Reconstruction of large rotator cuff tendon defects with porcine small intestinal submucosa in an animal model

Large rotator cuff tears represent a challenging problem. The purpose of our study was to evaluate the small intestinal submucosa (SIS) extracellular matrix in reconstruction of such defects in an animal model. Forty rats were equally divided into an SIS group (reconstruction of a large supraspinatus tendon defect by use of the SIS) and a defect group (no repair). The operative and contralateral normal shoulders underwent histologic evaluation and biomechanical testing at 6 and 16 weeks. Neovascularization and fibroblastic ingrowth were present in SIS-regenerated tendons, which had an ultimate force to failure that was 78% of normal at 16 weeks. This was higher than in the defect group, which demonstrated an ultimate force to failure that was 34% of normal (P = .008). The ultimate force to failure of the SIS-regenerated tendons approached that of the normal tendon at 16 weeks. The SIS extracellular matrix served as a scaffold promoting host tissue ingrowth and appears promising in the management of large rotator cuff defects in a rat model. However, human beings sustain tears at the bone-tendon interface and demonstrate decreased healing potential relative to rats. Therefore, the findings of this preliminary study should not be extrapolated to human beings without further investigation.