Biodegradable implants for the treatment of osteochondral defects in a goat model

Full-thickness, circular, 7 x 7 mm, osteochondral defects were created in the weight-bearing aspect of the medial femoral condyle in skeletally mature female Spanish goats. Four treatment approaches were used to manage the osteochondral defects. Defects were left (a) empty (negative control), (b) filled with a two-phase biodegradable polymeric implant, (c) filled with the implant plus 180 ng transforming growth factor beta (TGF beta), or (d) filled with the implant plus 1,800 ng TGF beta. At 16 weeks following surgery, resurfacing of osteochondral defects was found to be incomplete in all groups. Biomechanical and histologic evaluation of the neocartilage showed that slightly better quality repair was promoted by the two implant groups containing TGF beta. The use of the two-phase biodegradable implant for delivering TGF beta seems to be beneficial insofar as structural quality of subchondral bone is concerned, although even in these two groups new cartilage did not fill the defects completely.