SLR - July 2019 - Bridget Metzo

Three Week vs. Six Week Immobilization for Stable Weber B Type Ankle Fractures: Randomized, Multicenter, Non-Inferior Clinical Trial

Reference: T. Kortekangas, H. Haapasalo, T Flinkkila, P. Ohtonen, S. Nortunen, H. Laine, et al. Three Week vs. Six Week Immobilization for Stable Weber B Type Ankle Fractures: Randomized, Multicenter, Non-Inferior Clinical Trial. BMJ 2019 ;364 :k5432.

Scientific Literature Review

Reviewed By: Bridget Metzo, DPM
Residency Program: University Hospital – Newark, NJ

Podiatric Relevance: Ankle fractures are one of the most common Emergency Room consultations for a podiatric surgeon at a level one-trauma center. Depending on the stability, level of displacement, and the patient, the fractures are treated surgically or non-surgically. With non-surgical treatment, there are multiple ways to ensure off loading of a fracture. This article sought to determine if treatment with immobilization with a cast or orthotic for three weeks was non-inferior to six weeks of cast immobilization for patients with stable, isolated Weber B type fibula fractures.

Methods: A level 1 randomized, parallel group, non-inferiority study was performed. Patients were evaluated in the emergency room at two University Hospitals by Orthopedic surgeons. The primary exclusion criteria was the external rotation test. The primary outcome measure was the Olerud-Molander Ankle Score (OMAS), and the primary time point was 52 weeks. Treatment response was also assessed at weeks 6 and 12. Secondary outcome measurements included; FAOS, VAS, RAND-36, ROM, mal-union, and fracture union. Non-inferiority margin was evaluated at 10 percent. The between group differences were reported at 52 weeks with 95 percent confidence intervals derived from a repeated mixed model.

Results: A total of 247 patients were randomized into each group; 84 into the six-week cast, 83 into the three-week cast, and 80 into the three-week orthotic group. At this 52 weeks follow-up time point, the mean OMAS of the three study groups was 87.6 points (SD 18.3) in the six week cast group, 91.7 points (SD 12.9) in the three week cast group, and 89.8 points (SD 18.4) in the three week orthotic group. The only statistically significant between group difference in the OMAS was a 7.2 benefit of the three week case over the six week cast at 12 week. The only statistically significant between group difference in the secondary outcomes was a slightly improved ankle plantar flexion of those treated with the orthotic for three weeks vs. the six week group.

Conclusions: The authors concluded that ankle function and fracture healing in treatment with three weeks of cast immobilization or orthotics is not inferior to conventional six-week treatment. However, multiple DVTs were reported in the immobilization groups. Therefore, is total immobilization in a cast the best course of treatment? Or, is offloading in a CAM boot or orthotic preferable due to the ability to perform ROM and stretching exercises? In addition, two non-unions were reported in the three-week immobilization group, which the authors reported were random, rather than due to shorter treatment. Finally, it is imperative to present the patient with the treatment program best suited to the individual. 

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