Pre-contoured Allograft Wedge Resorption and Complication Rates in Foot and Ankle Surgery at a Single Institution from 2017-2022

Category: Other; Basic Sciences/Biologics Introduction/ Purpose: Structural allografts have long been used in foot and ankle reconstructive surgery. Pre-contoured allograft wedges, manufactured in a variety of shapes and sizes for specific uses, have gained popularity in recent years due to their ease of use and ability to decrease operative time. A high rate of resorption of such pre-contoured allograft wedges was noted anecdotally by the senior authors, particularly in 2022. There is no known literature describing this phenomenon and thus, the purpose of this study was to identify the resorption and complication rates of pre-contoured allograft wedges over time. Methods: A retrospective review of patients who had a pre-contoured allograft wedge (Paragon28, Englewood, CO) implanted during foot and ankle surgery between 2017 and 2022 at a single institution by one of 10 surgeons was performed. Chart review was used to obtain demographic and implant information and confirm the surgical procedure(s) performed. Radiographic review was completed in order to identify patients with graft resorption and/or nonunion, confirm the site of allograft implantation, and determine the method of fixation used at the allograft site. A linear regression model was utilized to determine if there was a statistically significant association between the year and the number of cases of resorption. Results: In the 320 patients that met inclusion criteria, there were 334 wedges implanted. There were 24 grafts that resorbed and an additional 10 wedges that developed a non-union without resorption. Resorption was noted as early as 5.7 weeks post-operatively and as late as 36.6 weeks post-operatively (average 12.9 weeks). Of the allografts that resorbed, the majority were Lapidus wedges (38%) and Cotton wedges (56%) (Table 1). Resorption rates were highest in the last 2 years studied (Figure 1). Of the 78 wedges used in 2022, 11 wedges resorbed and there were 3 non-unions without resorption, for an overall complication rate of 18%. There was a statistically significant association between the year and the number of patients that had graft resorption (p = 0.03). Conclusion: While complications of allograft wedges in foot and ankle surgery have previously been described, including nonunion, resorption of pre-contoured wedges has not. Over a 5-year period at a single institution, there was a wedge resorption rate of 7% and an overall radiographic complication rate of 10%. There was an increase in allograft resorption cases as well as overall resorption rate and complication rate in 2022 compared to previous years. The majority of cases in which there was a complication occurred with the use of a Cotton or Lapidus wedge; however, no concrete identifiable patient or surgical risk factors were identified.