No effect of subperiosteal growth factor application on periosteal neo-chondrogenesis in osteoperiosteal bone grafts for osteochondral defect repair.

PURPOSE: The purpose of this study was to examine the effect of subperiosteal injection of chondroinductive growth factors on the histological and biomechanical outcome of autologous osteoperiosteal grafts. METHODS: Thirty six standardised osteochondral defects were created in the trochlear groove of 18 Göttinger Minipigs and evaluated after six, 12 and 52 weeks. Defects were treated with press-fit implantation of autologous osteoperiosteal cylindrical block-grafts with or without subperiosteal injection of a chondroinductive growth factor mixture (GFM). RESULTS: Histomorphological analysis showed complete osseointegration of all grafts from six weeks. The periosteum remained in place in 35 of 36 cases. Fibrocartilagineous repair tissue formation occurred at the cambium layer with a maximum at 12 weeks in both groups. Histomorphological grading and biomechanical testing showed highest values at 12 weeks, with signs of tissue degradation at one year. There was no significant difference between both groups. CONCLUSION: Transplantation of autologous osteoperiosteal grafts is an effective method to restore subchondral bone defects, but not the overlying cartilage as the repair tissue deteriorates in the long term. Subperiosteal growth factors injection did not stimulate tissue differentiation on a biomechanical and histomorphological level.