SLR - September 2021 - Rhennetta J. Bork

Supination Adduction Ankle Fractures are Associated with Arthritis and Poor Outcomes

Reference: Benedick A, Kavanagh M, Audet M, Simske NM, Vallier HA. Supination Adduction Ankle Fractures are Associated with Arthritis and Poor Outcomes. J Orthop Trauma. 2021 Jun 1;35(6):e195-e201.

Level of Evidence: Prognostic Level III

Scientific Literature Review

Reviewed By: Rhennetta J. Bork, DPM
Residency Program: Ascension St. John Hospital – Detroit, MI

Podiatric Relevance: Supination adduction (SAD) fracture patterns make up 5-20 percentof ankle fractures, but few studies have evaluated the complications and functional outcomes related to this fracture type. SAD injuries are characterized by two stages: a transverse infra-syndesmotic distal fibular fracture or talofibular ligament rupture (type I), followed by longitudinal fracture of the medial malleolus (type II) with impact of the talus on the tibial plafond, which is unique to the SAD fracture pattern and damages articular cartilage. The purpose of this study was to compare injury features, complications and functional outcomes between SAD type II fractures and traditional torsional ankle injuries (TAI).

Methods: The authors performed a retrospective cohort study evaluating patients with TAI or SAD injury between 2003 and 2018. 65 adults with type II SAD injuries were eligible for inclusion. The 200 most recent consecutive adults with TAI with six months of follow-up were chosen as controls. Demographic information, including age, sex, race, BMI, comorbidities, and substance use, were evaluated. Complications included superficial infection, deep infection, wound-healing complications, nonunion, malunion and post-traumatic arthrosis (PTA). Unplanned secondary procedures were also recorded. Patient-reported outcomes were assessed using the Foot Function Index (FFI) and Short Musculoskeletal Function Assessment (SMFA).

Results: Two hundred sixty-five patients (65 SAD and 200 TAI) were analyzed, with similar baseline demographics noted. The mean age was 46.6 years; with the SAD injury group noted to be younger (43.2 vs. 47.7). BMI was lower in the SAD group (28.1 vs 32.2). Overall comorbidities were not different between groups. Associated dislocations, bimalleolar fractures, and concomitant hindfoot injuries to the talus were more common in the SAD group. SAD injuries more commonly resulted from high-energy vehicular collisions (58.5 percent vs. 29.0 percent). TAIs were most frequent after ground-level falls (51.0 percent vs. 21.5 percent). The overall complication rate was 18.9 percent with no difference between groups. Eighty percent of patients developed PTA after a SAD injury compared with 48 percent after TAI. The overall rate of unplanned secondary procedures was 18.9 percent, with no difference between groups. The mean FFI and SMFA scores were reported after an average of 4.4 years and were higher among SAD patients for all subcategories, indicating poorer outcomes, although there were no significant differences between groups.

Conclusions: SAD fractures accounted for 4.2 percent of fractures and occurred in younger patients through higher mechanism injuries. SAD fractures were associated with worse patient-reported outcome measures; however, this was not significant. Complications and unplanned secondary procedures were similar, despite 80 percent developing PTA after SAD injuries, which occur secondary to marginal plafond impaction. These findings can be used to counsel patients regarding complications and outcomes after an SAD injury.

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