Delivering rhFGF‐18 via a bilayer collagen membrane to enhance microfracture treatment of chondral defects in a large animal model

Augmented microfracture techniques use growth factors, cells, and/or scaffolds to enhance the healing of microfracture‐treated cartilage defects. This study investigates the effect of delivering recombinant human fibroblastic growth factor 18 (rhFHF18, Sprifermin) via a collagen membrane on the healing of a chondral defect treated with microfracture in an ovine model. Eight millimeter diameter chondral defects were created in the medial femoral condyle of 40 sheep ( n  = 5/treatment group). Defects were treated with microfracture alone, microfracture + intra‐articular rhFGF‐18 or microfracture + rhFGF‐18 delivered on a membrane. Outcome measures included mechanical testing, weight bearing, International Cartilage Repair Society repair score, modified O'Driscoll score, qualitative histology, and immunohistochemistry for types I and II collagen. In animals treated with 32 μg rhFGF‐18 + membrane and intra‐articularly, there was a statistically significant improvement in weight bearing at 2 and 4 weeks post surgery and in the modified O'Driscoll score compared to controls. In addition, repair tissue stained was more strongly stained for type II collagen than for type I collagen. rhFGF‐18 delivered via a collagen membrane at the point of surgery potentiates the healing of a microfracture treated cartilage defect. © 2015 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 33:1120–1127, 2015.