Successful Outcomes With Nonoperative Treatment and Immediate Weightbearing Despite Stress-Positive Radiographs in Isolated Distal Fibula (OTA/AO 44B) Fractures.

Objectives: To determine whether a nonoperative management protocol results in equivalent outcomes in isolated OTA/AO 44B (Weber B) fractures without initial medial clear space (MCS) widening regardless of stress radiography findings.

Methods:

Design: Prospective cohort.

Setting: Level 1 academic trauma center.

Patient selection criteria: Nonoperatively managed patients with isolated OTA/AO 44B fractures and MCS ≤4 mm on initial non-weightbearing injury radiographs between from January 2018 and January 2022 were included. All patients underwent emergency department gravity stress radiographs and those with widening were considered the widening cohort and those without the non-widening cohort.

Outcome measure and comparisons: MCS measurements on weightbearing radiographs were obtained at first follow-up, 6 weeks, 12 weeks, and 6 months postinjury, were considered indicative of instability if >4 mm and were compared between cohorts.; American Orthopaedic Foot and Ankle Society ankle-hindfoot scores were also compared between cohorts.

Results: Sixty-nine patients were studied. None of the 38 patients (55%) with widening on gravity stress radiographs demonstrated widening with weightbearing radiographs at any time point. Mean MCS measurement differences between the 2 cohorts were statistically significant for all time points ( P = 0.012); however, with a model adjusted mean MCS value of 2.7 mm for the nonwidening cohort and 2.9 mm for the widening cohort, these are not clinically significant. There was no statistically significant difference in overall final American Orthopaedic Foot and Ankle Society scores between the 2 groups ( P = 0.451). In addition, statistical equivalence using Schuirmann 2 one-sided tests was achieved between the 2 groups. Both cohorts had mean American Orthopaedic Foot and Ankle Society scores representing excellent outcomes at the final follow-up.

Conclusions: Patients with isolated OTA/AO 44B fractures without MCS widening on initial injury radiographs did not demonstrate instability on subsequent weightbearing radiographs and had equivalent outcomes regardless of gravity stress radiography findings when treated nonoperatively. Weightbearing radiographs at the initial follow-up appear to be a reliable assessment of ankle stability in these injuries and are an appropriate alternative to painful and time-consuming stress radiography.

Level of evidence: Therapeutic Level II. See Instructions for Authors for a complete description of levels of evidence.