Weight bear then discharge: A safe management strategy for isolated Weber B lateral malleolus fractures – outcomes of 658 patients

D.H. Martin, N.T.H. Ng, B. Armstrong, J. Brennan, T. Feng, K. Lekuse, T.O. White, S.P. Mackenzie

Background: Myriad protocols exist for the evaluation of isolated Weber B lateral malleolus fractures that demonstrate a congruent tibiotalar joint on initial radiographic evaluation. Manual stress, gravity stress and weight-bearing radiographs, all at various timepoints, may be employed to identify those injuries that develop significant talar shift but consensus is elusive. This study outlines a safe and reproducible protocol for such injuries, utilising a removable orthosis, immediate weight bearing and standard supine radiographs.

Method: A retrospective analysis of a prospective trauma database was analysed to identify patients with an isolated Weber B ankle fracture with adequate presentation radiographs demonstrating a congruent mortise. Patient records and radiographs were evaluated a minimum of 5 years after initial presentation to determine ankle stability, complications, and the burden on outpatient services.

Results: Between 2014 and 2016, 657 patients were referred to the specialist trauma clinic from the emergency department. Of the 657, 52 patients had inadequate ED radiographs to determine ankle congruity. At the two-week assessment, 11 of the 52 demonstrated talar shift and required intervention. Therefore 646 patients demonstrated ankle congruity at two weeks after weight bearing. No patient demonstrated talar shift at the six-week assessment. Average number of follow up appointments was 2.4 with 3.5 radiographs. Our new treatment protocol advocates discharge after a single orthopaedic assessment after two weeks of weight bearing. This protocol will reduce outpatient appointments and radiographic series by 58% and 43% respectively.

Conclusion: This study supports immediate weight-bearing of Weber B ankle fractures with a congruent mortise in an orthosis. Follow up beyond two weeks is unnecessary and our protocol offers a safe means of significantly reducing the outpatient burden.