The purpose of this study was to quantify the levels of growth factors (platelet-derived growth factor [PDGF] AB, vascular endothelial growth factor [VEGF], insulin-like growth factor [IFG] 1, and transforming growth factor [TGF]- β1) within bone samples at the fusion site of diabetic patients undergoing hindfoot arthrodesis to determine any correlation with successful fusion.
The study included 10 adult diabetic patients from one US center, with an average age of 57.9 years (range 49–71 years). Interventions included hindfoot arthrodeses with a fixator (n=8) and pantalar arthrodeses with fixator (n=2). During each procedure, a bony bed sample was taken from the fusion site and frozen. This local bone bed was analyzed for growth factors using ELISA kits. A platelet-rich plasma (PRP) concentration was applied to each fusion site during the procedure.
Three of the ten patients had a nonunion. After normalizing to bicinchoninic acid assay (BCA) total protein levels, a 70% decrease in PDGF-AB (0.044 pg/μg non-union to 0.149 pg/μg union; P=0.016) and a 44% decrease in VEGF (0.522 pg/μg non-union to 0.924 pg/μg union; P=0.031) were observed in the three nonunion bone samples compared with the arthrodesis group. No difference existed in the levels of IGF-I between the groups. Insignificantly higher levels of TGF-β1 were detected in the nonunion group (0.199 ng/μg non-union to 0.142 ng/μg union; P=0.544).
Significant differences in local growth factor (PDGF, VEGF) levels exist between diabetic patients who achieve union and non-union. Potentially, growth factor levels, PDGF-AB and VEGF, in bone may affect the outcome of successful arthrodesis in diabetic patients. This study supports the concept that growth factor levels within the fusion site of a diabetic patient may affect the outcome of a successful hindfoot arthrodesis.