Background: Isolated lateral malleolus fractures account for a significant proportion of ankle fractures, and complications related to surgical treatment are common. This study aimed to assess the feasibility of conservative treatment with walker boot and immediate weightbearing as tolerated for Weber B / supination-external rotation (SER) lateral malleolus fracture, by comparing stable (SER2) and potentially unstable (SER4a) fractures. The distinction between stable and unstable fractures is crucial to guide treatment decisions. Methods: This prospective study included patients with Weber B/SER lateral malleolus fractures who met specific criteria. Fracture stability was assessed via medial clear space (MCS) measurement on weightbearing radiographs and conservative (walker boot and immediate weightbearing as tolerated) or surgical treatment was determined accordingly. Clinical and functional outcomes—including visual analog scale (VAS), American Orthopaedic Foot & Ankle Society (AOFAS) scores, Foot and Ankle Ability Measure (FAAM) scores, and 36-Item Short Form Health Survey (SF-36) scores—were evaluated in outpatient clinic follow-up, with a minimum duration of 12 months. Results: Out of 155 identified Weber B fractures with MCS <7 mm, 141 patients completed follow-up: 114 with SER2 and 27 with SER4a fractures. The SER2 group demonstrated excellent outcomes at 12 months (VAS 0.1, AOFAS 98.9, FAAM activities of daily living (ADL)/Sport 99.4/99.6), with 98.2% return to sport, 100% return to work, and 100% return to ADL. The SER4a group demonstrated comparable outcomes at 12 months (VAS 0.0, AOFAS 100, FAAM ADL/Sport 100/100), with full return to sport, work, and ADL. One patient in the SER4a group evolved to nonunion and required surgery during follow-up. With the numbers available, no significant intergroup differences in outcome scores or return to function could be detected. Conclusion: This study supports conservative treatment—with walker boot and immediate weightbearing as tolerated—for stable SER2 lateral malleolus fractures, and was associated with reduced need for surgery and lower exposure to surgical complications. It also suggests that potentially unstable SER4a fractures may achieve comparable outcomes under the same conservative protocol. Weightbearing radiographs assessment with MCS measurement appears to be an effective method for guiding treatment decisions in Weber B/SER lateral malleolus fractures. Level of Evidence: Level II, therapeutic, prospective cohort study.
Cunha et al. (Wed,) studied this question.