The With Or Without Olecranon K-wire (WOW OK) Trial of tension band wire fixation versus cerclage fixation without K-wires in displaced stable olecranon fractures: study protocol for a randomized controlled trial

BACKGROUND: Displaced olecranon fractures with a stable elbow joint are classified as Mayo type 2a or 2b and are commonly operated with tension band wiring, i.e. two K-wires and a cerclage. Retrospective studies have reported fewer reoperations and complications with cerclage fixation alone when compared to tension band wiring, though with similar long-term results. We decided to compare tension band wiring to cerclage fixation of displaced, stable olecranon fractures in adults in a randomized controlled trial. METHODS: All patients ≥ 18 years old with Mayo type 2a and 2b fractures presenting at Skåne University hospital will be eligible for study inclusion, unless exclusion criteria are met. Two hundred participants will be included and randomized 1:1 to cerclage fixation or tension band wiring. Outpatient physiotherapist follow-up appointments will be scheduled at 2 and 6 weeks and at 3, 12, and 36 months at the Dept. of Orthopaedics. A lateral view radiograph of the elbow will be analysed at 6 months. The primary outcome of our study is the rate of reoperations. Secondary outcomes are complication rates, severity of complications, and patient-reported outcome measures (QuickDASH, Short Musculoskeletal Function Assessment, pain level, and patient satisfaction). The sample size was calculated to give 80% power for detecting a statistically significant difference in reoperation rates (with alpha-value 0.05), based on a previous retrospective study. DISCUSSION: Reoperation and complication rates after tension band wiring of olecranon fractures are high. Treatment of these injuries is debated, and several ongoing trials compare tension band wiring with plate fixation, suture fixation, and non-operative treatment. As data from retrospective studies indicate that cerclage fixation may be superior to tension band wiring, we see a need for a randomized controlled trial comparing these methods. The WOW-OK Trial aims to obtain level-1 evidence that may influence treatment choice for this type of fracture. TRIAL REGISTRATION: ClinicalTrials.gov NCT05657899. Registered on 16 November 2022. The trial complies with SPIRIT and CONSORT guidelines. The SPIRIT figure is found in Table 2. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s13063-023-07566-9.