University of Oulu

Kortekangas T, Lehtola R, Leskelä H-V, et al. Surgery versus non-operative treatment for ER-stress unstable Weber-B unimalleolar fractures: a study protocol for a prospective randomized non-inferiority (Super-Fin) trial. BMJ Surg Interv Health Technologies 2021;3:e000098. doi:10.1136/bmjsit-2021-000098

Surgery versus non-operative treatment for ER-stress unstable Weber-B unimalleolar fractures : a study protocol for a prospective randomized non-inferiority (Super-Fin) trial

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Author: Kortekangas, Tero1,2; Lehtola, Ristomatti1,2; Leskelä, Hannu-Ville1,2;
Organizations: 1Department of Orthopaedics and Traumatology, Oulu University Hospital, Oulu, Finland
2Medical Research Center Oulu, Oulu, Finland
3Finnish Centre for Evidence-Based Orthopaedics (FICEBO), Department of Orthopaedics and Traumatology, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
4Department of Surgery, Oulu University Hospital, Oulu, Finland
5Pohjola Hospital, Helsinki, Finland
6Pohjola Hospital, Oulu, Finland
Format: article
Version: published version
Access: open
Online Access: PDF Full Text (PDF, 0.8 MB)
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Language: English
Published: BMJ, 2021
Publish Date: 2022-02-28


Roughly two-thirds of ankle fractures are unimalleolar injuries, the Weber B-type fibula fracture being by far the most common type. Depending on the trauma and the accompanying soft-tissue injury, these fractures are either stable or unstable. Current clinical practice guidelines recommend surgical treatment for unstable Weber B-type fibula fractures. An ongoing randomized, parallel group, non-inferiority trial comparing surgery and non-operative treatment for unstable Weber B-type ankle fractures with allocation ratio 1:1. The rationale for non-inferiority design is as follows: By being able to prove non-inferiority of non-operative treatment, we would be able to avoid complications related to surgery. However, the primary concern related to non-operative treatment is increased risks of ankle mortise incongruency, leading to secondary surgery, early post-traumatic osteoarthritis and poor function. After providing informed consent, 126 patients aged 16 years or older with an unimalleolar Weber B-type unstable fibula fracture were randomly assigned to surgery (open reduction and internal fixation) or non-operative treatment (6-week cast immobilization). We have completed the patient enrolment and are currently in the final stages of the 2-year follow-up. The primary, non-inferiority outcome is the Olerud-Molander Ankle Score (OMAS) at 2 years (primary time point). The predefined non-inferiority margin is set at 8 OMAS points. Secondary outcomes include the Foot and Ankle Score, a 100 mm Visual Analogue Scale for function and pain, the RAND-36-Item Health Survey for health-related quality-of-life, the range-of-motion of the injured ankle, malunion (ankle joint incongruity) and fracture union. Treatment-related complications and harms; symptomatic non-unions, loss of congruity of the ankle joint, reoperations and wound infections will also be recorded. We hypothesize that non-operative treatment yields non-inferior functional outcome to surgery, the current standard treatment, with no increased risk of harms.

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Series: BMJ surgery, interventions, & health technologies
ISSN: 2631-4940
ISSN-E: 2631-4940
ISSN-L: 2631-4940
Volume: 3
Issue: 1
Article number: 000098
DOI: 10.1136/bmjsit-2021-000098
Type of Publication: A1 Journal article – refereed
Field of Science: 3126 Surgery, anesthesiology, intensive care, radiology
Funding: This study was supported by the Oulu University Hospital and by Competitive State Research Financing of the Expert Responsibility area of Oulu University Hospital; grant number 9R006.
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