Repair of full-thickness cartilage defects in rabbit knees with free periosteal graft preincubated with transforming growth factor.

This study compared different concentrations of transforming growth factor-beta 1 (TGF-beta1) used for short-term preincubation in vitro of large periosteal explants to determine the effect of chondrogenesis and the fate of repair cartilage over time. Eighty-two rabbits were divided into four groups: group A, non-grafted; group B, non-incubated grafted; group C, 100 ng/mL recombinant human (rh) TGF-beta1 preincubated grafted; and group D, 20 ng/mL rhTGF-beta1 preincubated grafted. Rabbits from each group were sacrificed at intervals between 2 and 24 weeks. Histologic slides were stained with safranin O and were scored based on a subjective scoring system. Group A healed with non-cartilaginous material. Group B healed with hyaline cartilage-like material with progressive thinning of this regenerated layer; at 24 weeks, this layer was fibrous tissue. Group C enhanced repair with hyaline cartilage-like material but accelerated early degeneration and osteophyte formation; the cartilage became fibrous tissue at 24 weeks. Group D did not enhance cartilaginous repair. At 24 weeks, all groups had the same result. The 100 ng/mL rhTGF-beta1 preincubation in vitro with periosteum enhanced early osteochondral repair but did not show prolonged durability. Clinical application of this growth factor necessitates further study.