Is 2-week Cast Wearing Followed by 4-week Functional Bracing Superior to 6-week Cast Immobilization After Surgery for Ankle Fractures? A 2-year Follow-up of a Randomized Controlled Trial

Background Functional orthoses offer comparable outcomes to traditional casting in function and symptom relief after ankle fracture surgery, with the potential benefit of improved patient comfort and mobility. Even though early functional treatment after ankle fracture surgery shows promise, uncertainties about functional outcomes, symptom relief, and wound complications remain. Questions/purposes (1) Are the functional outcomes 12 weeks after injury of patients treated with functional bracing (2 weeks of cast immobilization followed by 4 weeks of functional bracing) superior to those of patients who undergo 6 weeks of cast immobilization after ankle fracture surgery? (2) Are the functional outcomes 2 years after injury of patients treated with functional bracing as described above superior to those of patients who undergo 6 weeks of cast immobilization after ankle fracture surgery? (3) Are adverse events, particularly wound complications, more common in patients treated with functional bracing than those treated with cast immobilization? Methods Between November 2005 and December 2012, a total of 134 patients (mean [range] age 40 years [18 to 59], 51% women) with an ankle fracture were enrolled in a randomized trial at one institution. Because of organizational changes, data collection and analysis were delayed. However, the study questions remain relevant, as most patients had bimalleolar or trimalleolar fractures, which are still treated surgically, and the postoperative protocols from the original study that were evaluated in this report remain widely used today. The indications for surgery were acute displaced lateral malleolar ankle fracture with > 2 mm of displacement (31% [42 of 134]), bimalleolar fracture (49% [65]), or trimalleolar fracture (20% [27]). After surgery and an initial 2-week period of cast immobilization, participants were randomized into functional bracing (n = 73) using a prefabricated ankle orthosis and cast immobilization (n = 61) with a custom-made below-knee fiberglass cast for an additional 4 weeks. In the bracing group, 3% (2 of 73) were lost to follow-up at 12 weeks and 14% (10) at 2 years, with 86% (63) fully analyzed. In the casting group, 2% (1 of 61) were lost to follow-up at 12 weeks and 20% (12) at 2 years, with 80% (49) fully analyzed. There were no differences in the baseline characteristics between the study groups. The primary outcome measure was the patient-reported Olerud-Molander Ankle Score (OMAS; scale from 0 to 100, with higher scores indicating better outcomes and fewer symptoms), assessed at 12 weeks (minimum clinically important difference [MCID] 15.0) and at 2 years (MCID 9.5). We also assessed the frequency of postoperative adverse events, including wound infections. A repeated-measures mixed model was used for statistical analyses of the primary outcome. Results At 12 weeks, we found no clinically important difference between the bracing group (mean ± SD 58 ± 23) and the casting group (50 ± 19) in OMAS score (mean difference 8 [95% confidence interval (CI) 2 to 14]; p = 0.008). At 2 years, we found no difference between the bracing group (91 ± 11) and the casting group (88 ± 14) in OMAS score (mean difference 3 [95% CI -3 to 9]; p = 0.29). The frequency of treatment-related adverse events, particularly wound complications, likewise did not differ between the groups and was 26% (19 of 73) in the bracing group and 23% (14 of 61) in the casting group (p = 0.68). Conclusion Given these findings, surgeons can consider either treatment strategy based on patient preferences, clinical context, and resource availability without compromising clinical outcomes. However, functional bracing may enhance comfort and mobility during recovery while requiring fewer resources. Future studies should identify specific patient subgroups that may benefit more from either strategy and evaluate factors such as cost-effectiveness and patient satisfaction. Level of Evidence Level I, therapeutic study.