THE USE OF XENOGENEIC SMALL-INTESTINAL SUBMUCOSA AS A BIOMATERIAL FORACHILLES-TENDON REPAIR IN A DOG-MODEL

A study was conducted to evaluate the tissue response to a xenogeneic biomaterial when this material was used to repair an experimentally in duced Achilles tendon defect in the dog. Twenty dogs had a 1.5 cm segm ental defect of the Achilles tendon created surgically which was then repaired with acellular connective tissue derived from porcine small i ntestinal submucosa (SIS). The animals were sacrificed at 1, 2, 4, 8, 12, 16, 24, and 48 weeks and the neotendons examined for uniaxial long itudinal tensile strength, morphologic appearance, hydroxyproline (col lagen) content, and disappearance of the originally implanted SIS mate rial over time. The contralateral normal Achilles tendons served as co ntrols as did four additional dogs that had a 1.5 cm segmental Achille s tendon defect created surgically without subsequent surgical repair with SIS. Results showed the SIS remodeled neotendons to be stronger t han the musculotendinous origin or the boney insertion (>1000 N) by 12 weeks after surgery and to consist of organized collagen-rich connect ive tissue similar to the contralateral normal tendons. The four dogs in which no SIS was implanted showed inferior strength at the comparab le time points of 4, 8, 12, and 16 weeks. Immunohistochemical studies suggest that the SIS biomaterial becomes degraded within the first eig ht weeks and serves as a temporary scaffold around which the body depo sits appropriate and organized connective tissue. SIS is a promising b iomaterial worthy of further investigation for orthopedic soft tissue applications. (C) 1995 John Wiley & Sons, Inc.