Does use of Allograft Affect Union Rates in Minimally Invasive Hallux Valgus Surgery?

Category: Bunion; Basic Sciences/Biologics Introduction/Purpose: Hallux valgus is a common foot deformity that can cause significant discomfort. Surgical correction of hallux valgus can be achieved through various techniques with minimally invasive surgery (MIS) gaining popularity amongst surgeons. The use of allograft in traditional open approaches has been proposed to improve the outcomes of hallux valgus repair by expediting time to union. We performed a retrospective analysis of patients undergoing MIS hallux valgus correction with and without the allograft at time of surgery. The primary aim of our study was to determine if use of allograft in hallux valgus MIS correction led to different time to union as well as rate of unions. Methods: A retrospective analysis was conducted to compare outcomes of patients who underwent hallux valgus correction with or without allograft. Patients included in the analysis underwent primary hallux valgus correction using third generation minimally invasive techniques and had postoperative weightbearing x-rays. Exclusion criteria included revision surgery, open surgeries, and loss-to-follow up. All surgeries were performed by three fellowship trained Foot and Ankle Orthopaedic surgeons at a single center from September 2019 to December 2022. All patients had similar post operative protocols. The allograft group received 2- 5 cc’s of a demineralized bone matrix (DBM) gel. Radiographs were evaluated by two independent orthopedic surgeons who were blinded to the patient's group allocation. The primary outcome of this study was time to radiographic union and rate of union. The data was analyzed using the independent t- test for continuous variables and the Fisher Exact test for categorical variables. Results: Seventy-two patients (77 feet) met inclusion criteria: allograft group (n=25) and a control group (n=52). Demographics between both groups were similar; the overall demographics can be found in Table 1. In our study, all 77 feet obtained complete union and no malunions or non-unions were observed in either group. The average time to complete union for the allograft group was 3.52 months (± 1.58) and the control group was 4.36 months (± 2.20); union times between groups did not reach statistical significance (p = 0.09) but did demonstrate a trend towards significance (Figure 1.) Maintenance of surgical correction was observed in all patients. Conclusion: While there was no statistically significant difference in union time and/or rates between the allograft group and control group, the allograft recipients had a reduction in the average time to union post MIS hallux valgus correction. No differences were observed with regards to radiographic recurrence nor complications between the two groups. This study suggests that demineralized bone matrix allograft may potentially decrease time to union but further studies are needed to confirm this.