Comparison of ulnar shortening osteotomy for idiopathic ulnar impaction syndrome using conventional or ulnar osteotomy plates and with or without interfragmentary screw fixation

Purpose This study investigated the impact of plate type on the clinical and radiological outcomes of ulnar shortening osteotomy (USO) by comparing conventional and ulnar osteotomy plates. The effect of interfragmentary screw fixation (ISF) during USO was also assessed.Methods Seventy-eight patients were divided into three groups according to the type of plate: 3.5-mm dynamic compression plate (DCP), 3.5-mm limited contact DCP, and 2.7-mm locking compression plate ulna osteotomy system (all from Depuy-Synthes). The patients were also divided into two groups according to whether ISF was performed. Clinical and radiological outcomes, including time to bone union, presence of delayed union, and refracture after hardware removal, were analyzed. Other factors that might affect bone union, such as smoking and underlying diseases, were also evaluated.Results No significant differences were found in clinical and radiological outcomes according to the type of plate. Eight of 51 patients (15.7%) in the without-ISF group showed delayed bone union. Forty-three patients in the without-ISF group underwent hardware removal, and refracture due to low-energy trauma after hardware removal was observed in five of those 43 patients (11.6%). Bone union time was significantly shorter in the with-ISF group (7.6±2.7 weeks vs. 9.8±6.6 weeks). Diabetes mellitus and ISF were associated with the delayed bone union.Conclusion The plate type had no influence on the clinical and radiological outcomes of USO in patients with idiopathic ulnar impaction syndrome. However, ISF during USO has several advantages, such as early bony union and prevention of refracture after hardware removal.