Intra-articular injection of rhFGF-18 improves the healing in microfracture treated chondral defects in an ovine model

Microfracture is a common cartilage repair procedure. Strategies to improve healing post-microfracture include the use of growth factors to enhance hyaline cartilage production. This study investigates the effect of intra-articular recombinant human fibroblastic growth factor 18 (rhFHF18) on the healing of a chondral defect treated with microfracture in an ovine model. Chondral defects (8 mm diameter) were created in the medial femoral condyle of 80 sheep (n = 16/treatment group). Defects were treated with microfracture alone or microfracture + intra-articular rhFGF-18 (administered either as one or two cycles of 3× weekly injections). Outcome measures included mechanical testing, macroscopic International Cartilage Repair Society repair score, modified O'Driscoll histology score, qualitative histology, and immunohistochemistry for types I, II, and VI collagen. In treated animals, there was a statistically significant improvement in ICRS tissue repair score and tissue infill score, in the modified O'Driscoll score between control and 1 cycle of rhFGF-18 at 6 m, and in the cartilage repair score and structural characteristic score between the control and both rhFGF-18 groups at 6 m. There was no evidence of degeneration of adjacent cartilage in the rhFGF-18 treated cartilage. The increase in hyaline cartilage-like tissue formed in the microfracture + rhFGF-18 treated groups indicates that rhFGF-18 potentiates the formation of hyaline cartilage repair following microfracture.