The Effect of Allograft vs Autograft and BMI on Outcomes, Complications, and Union Rate following Hindfoot Arthrodesis Procedures

Research Type: Level 3 - Retrospective cohort study, Case-control study, Meta-analysis of Level 3 studies Introduction/Purpose: BMI is a patient factor that has been found to influence patient outcomes following various orthopaedic interventions. While such literature is limited in the foot and ankle community, it was recently identified that BMI may impact patient reported outcomes and complications following hindfoot arthrodesis. While autograft is considered the gold-standard bone grafting material for arthrodesis, newer generation allograft strategies are a readily available alternative that may mitigate many postoperative complications. Current literature is limited regarding how allograft may impact the complications and outcomes following hindfoot arthrodesis observed in patients of various BMI. Accordingly, the current study analyzed the interaction between a patient’s BMI and grafting material and their impact on the rate of fusion, complications, and improvement in patient reported outcomes following hindfoot arthrodesis. Methods: A retrospective review was performed on patients who underwent hindfoot arthrodesis procedures between March 2021 and May 2023 at a single academic institution. A total of 70 hindfoot arthrodesis procedures were included in the current study. All patients were > 18 years of age at the time of surgery and all had > 12 months of follow-up. Demographic information, graft specifications, Patient Reported Outcome Measurement Information System (PROMIS) scores and postoperative complications were recorded for each patient. Outcomes were compared in relation to BMI and with respect to grafting material utilized (allograft/autograft/no bone graft) Categorical and continuous data were compared using Chi-squared test and analysis of variance (ANOVA), respectively; all p< 0.05 (*) were considered statistically significant. Results: Following hindfoot arthrodesis with allograft, patients with a BMI < 40 had a lower rate of wound dehiscence (p=0.044*) and overall complications (p=0.036*) in comparison to patient with a BMI > 40. A reduction in wound infections (p=0.015*), wound dehiscence (p=0.041*), and overall complications (p=0.041*) was also observed in patients with a BMI < 40 who underwent hindfoot arthrodesis with allograft + autograft. An overall rate of 17.4% and 16.7% nonunion was observed in patients with a BMI < 40 and patients with a BMI > 40, respectively. No difference in union rate was observed between BMI cohorts in patients who received allograft, autograft, allograft + autograft, or no bone graft. Conclusion: When compared to patients with a larger BMI, patients with a BMI < 40 were found to have fewer wound complications and total complications following hindfoot arthrodesis utilizing allograft or allograft + autograft. While there was no difference in union rate following hindfoot arthrodesis between BMI cohorts, data in the current study suggest BMI may serve as a predictor of patient outcomes and/or complications following various hindfoot arthrodesis procedures.