Effects of a novel hydrogel on equine bone healing: A pilot study

Objective: To examine the efficacy and biocompatibility of a thiolated gelatin-thiolated carboxymethyl hyaluronan (CMHA-SGX) sponge as an osteoconductive device in an equine second and fourth metacarpal bone defect model. Methods: Seven millimetre segmental ostectomies were created bilaterally in the second and fourth metacarpal bones of four horses. The left and right metacarpal defects were randomly assigned to (1) be filled with a CMHA-SGX sponge (treated) or (2) were left unfilled (control). The duration of the study was nine weeks. Bone healing was evaluated using serial radiology, as well as histologically and histomorphometrically. Data were analyzed using an analysis of variance (ANOVA). The level of significance was p < 0.05. Results: Serial radiographic evaluation revealed improved healing in the treated compared to the control defects at weeks eight and nine (p = 0.02). This finding was not corroborated histologically. Histomorphometry did not reveal any significant differences in healing between experimental groups. The CMHA-SGX sponge did not inhibit bone formation, induce local inflammation or lead to surgical site infection. Clinical significance: While further optimization to improve osteoconductive properties should be considered, the CMHA-SGX sponge appears to be a biocompatible orthopaedic implant and its use as a carrier for osteogenic proteins warrants further investigation.