The effect of fibroblast growth factor-2 on autologous osteochondral transplantation

Abstract

In this study, we performed a mechanical analysis of the effect of fibroblast growth factor-2 (FGF-2) on autologous osteochondral transplantation in a rabbit model. A full-thickness cartilage defect (diameter: 5 mm; depth: 5 mm) made in the right femoral condyle was treated with osteochondral transplantation using an osteochondral plug (diameter: 6 mm; depth: 5 mm) taken from the left femoral condyle. The animals were divided into three groups: Group I, the defect was filled with 0.1 ml of gelatin hydrogel containing 1 microg of FGF-2; Group II, the defect was filled with 0.1 ml of gelatin hydrogel only; Group III, the defect was left untreated. Thereafter, osteochondral plugs were transplanted and the transplanted osteochondral grafts were evaluated mechanically and histologically at postoperative weeks 1, 3, 8 and 12. The structural property of the osteochondral graft was significantly greater in Group I than in Groups II and III at postoperative week 3. Histological analysis at 3 weeks revealed a tendency towards increased subchondral bone trabeculae in Group I compared with the other groups. Autologous osteochondral grafts transplanted with gelatin hydrogel containing FGF-2 acquired adequate stiffness at an early postoperative phase.

Fig. 1

Stiffness of the articular cartilage based on the calibration formula (N/m²). *indicates significant differences (p < 0.05)

Fig. 2a–d

Histological evaluation of the transplanted graft in Group I (defect filled with gelatin hydrogel including 1 μg of FGF-2). a At week 1, there was a slight gap between the graft and the recipient site. b At week 3, the gap had disappeared and the articular layer and subchondral bone increased and developed. c At week 8, the subchondral bone trabeculae had increased. d At week 12, the subchondral bone trabeculae had decreased and the transplanted graft was almost the same as in the other groups. The arrows indicate the margins of the graft (original magnification ×25)

Fig. 3a–c

Histological evaluation of the junction between the graft and the host (Group I: defect filled with gelatin hydrogel including FGF-2, Group II: defect filled with gelatin hydrogel only, Group III: defect in which neither hydrogel nor FGF was used). At week 3, the structural integrity of the subchondral bone was observed in all groups. Especially, the subchondral bone trabeculae in Group I (a) were increased and more developed than that in Groups II (b) and Group III (c). The arrows indicate the area of the graft and host (original magnification ×25)