Factors Associated With Kirschner Wire Backout After Tension Band Wiring for Olecranon Fractures: A Retrospective...

Tension band wiring (TBW) is widely used for olecranon fractures; however, posterior migration of Kirschner wires (K-wires), termed "backout," is a common complication. At our institution, during intramedullary fixation, the proximal ends of K-wires are bent by 180° and embedded into the olecranon fragment. This study aimed primarily to identify clinical and radiographic factors associated with K-wire backout after TBW for olecranon fractures, and secondarily to explore clinically relevant thresholds of insertion depth and backout distance in relation to postoperative symptoms and reoperation.

We retrospectively reviewed data from 34 patients with olecranon fractures who underwent TBW and intramedullary K-wire fixation at our institute between 2014 and 2023. The backout distance was measured using postoperative radiographs. Patients were divided into backout (≥ 5 mm) and non-backout (< 5 mm) groups, and their clinical and radiographic parameters were compared.

The mean follow-up period was 12 months. Irritation symptoms occurred in 11 (33%) of the cases, and implant removal was required in 18 (53%). The insertion depth was significantly shallower in the backout group than in the non-backout group. The data suggested that an insertion depth of approximately 4-5 mm may be a practical target to reduce the likelihood of clinically relevant backout. Although thinner K-wires (1.6 mm) were used more frequently in the backout group, diameter was not independently associated with backout. Backout exceeding approximately 7-8 mm was frequently observed in patients with irritation symptoms and those who underwent reoperation.

In this retrospective cohort, a shallower embedding depth of the bent K-wire tip was associated with a higher likelihood of postoperative backout. Ensuring sufficient insertion depth and the use of thicker wires, when feasible, may help reduce complications following TBW.