Nonunion After Using Procedure-Specific Instrumentations for Ulnar Shortening Osteotomy.

Objectives: The primary purpose of this study was to compare the rates of nonunion among different osteotomy designs (company brand) and the rates of nonunion between oblique and transverse osteotomies. We secondarily aimed to assess the differences in reoperation and hardware removal rates after ulnar shortening osteotomy (USO). Methods: A retrospective cohort study of patients undergoing ulnar shortening osteotomy between 2015 and 2022 in our institute amongst 17 providers resulted in 92 consecutive patients. We included skeletally mature patients who underwent USO for the ulnar impingement abutment diagnosis. Demographic information was collected, including age, gender, race/ethnicity, BMI, and medical comorbidities. Six brand-specific devices were used and compared to the conventional plate fixation. Nonunion was determined based on the final available radiograph with a minimum follow-up of four months. Results: Of the 92 patients, 83 (90%) had a bone union. There is a remarkable difference in union among implant brands, although statistical analysis was not performed due to the small number of patients in each group. Transverse osteotomy was significantly related to a higher nonunion rate. Out of nine patients with resultant nonunion (10%), three healed after revision surgery (3.2%), two were lost to follow-up (2.2%), and four remained asymptomatic despite radiographic nonunion (4.6%). Plate removal was performed in four patients (4.3%), all of whom were in the union group. Conclusion: Patients should be informed about the nonunion rate with possible subsequent secondary surgery. Using procedure-specific devices may have mitigated the risk of nonunion.