Factors influencing K-wire migration in tension-band wiring of olecranon fractures

Background: Tension-band wiring is a popular method of internal fixation for simple olecranon fractures. Although fracture union rates and clinical outcomes are good, up to 80% of patients require removal because of prominent/symptomatic metalwork. The current literature remains unclear as to the best orientation of the longitudinal wires to minimize hardware failure. The aim of this study was to determine the surgically modifiable factors related to spontaneous wire pullout. Methods: A retrospective review of hospital theater records over a period of 6 years was performed to identify all olecranon tension-band wire procedures. Preoperative radiographs were used to confirm and classify the fracture. Intraoperative and postoperative radiographs were analyzed for a number of wire-associated variables: wire length within the ulna, medullary/cortical position, parallelism of wires, proximal wire prominence, wire angle relative to the ulna, distance from the articular surface, fracture gap, and subsequent pullout. Results: A total of 182 wires were analyzed. The mean age was 52.5 years, and the mean radiographic follow-up period was 7.3 months. Intramedullary wires had a mean pullout of 5.5 mm compared with 2.4 mm for transcortical wires (P < .0001). A multiple regression model noted 7 independent variables affecting wire pullout: age, bent wires, medullary/transcortical wire positioning, proximal prominence, ulnar shaft angle, distance from the articular surface, and articular step. Conclusion: To minimize postoperative pullout of wires, we suggest anatomic reduction and transcortical wire orientation, without bending, in the subchondral bone close to the articular surface. Level of evidence: Level II, Retrospective Design, Prognosis Study. (C) 2014 Journal of Shoulder and Elbow Surgery Board of Trustees.