Healing of osteochondral grafts in an ovine model under the influence of bFGF

Purpose: The well-recognized limitations in cartilage healing have lead to the development of a number of resurfacing techniques for defects of joint surfaces. Autologous grafting has developed into 1 of the preferred methods of treatment for focal osteochondral lesions, although basic research on this topic remains sparse. Type of Study: In an animal study, questions regarding the healing of osteochondral transplants under the influence of basic fibroblast growth factor (bFGF) were addressed. Methods: Two osteochondral autologous transplantations (OAT), 1 in the weight-bearing surface of each femoral condyle, were performed on the ovine knee using a standard operative protocol. One of the grafts was bathed in phosphate buffered sulfate (PBS) containing 50 mug of recombinant human bFGF (rh-bFGF) directly before implantation. Two groups consisting of 10 sheep each were evaluated after 3 and 6 months, respectively. Results: During the evaluation of the specimens, neither osteophytes nor synovial changes were observed. Macroscopically, the superficial border of the transplanted osteochondral plug could easily be outlined at both time periods, even though the cartilage interface of the rh-bFGF specimens was less demarcated. Radiographically, a solid osteointegration of the graft could already be documented at 3 months in the control group. In contrast, integration of the chondral surface of the OAT was not seen macroscopically or microscopically at any point. A firm physical interdigitation of the reconstructed joint surface could not be demonstrated in either of the 2 groups. The augmentation with rh-bFGF stimulated the osseous ingrowth, but was not able to improve chondral healing. Conclusions: The lack of integration of the cartilaginous portion of the transplanted plugs into the reconstructed joint surface, even following augmentation with bFGF, leads to questions regarding the long-term survival of the joint itself.