Objective/Hypothesis: Extra-articular ulnar-shortening osteotomy is a common procedure for the surgical treatment of ulnar impaction syndrome. Several techniques for this osteotomy have been developed to avoid the morbidity associated with a standard transverse osteotomy. However, these techniques require special instrumentation and are expensive. The purpose of this study was to evaluate the outcome of step-cut ulnar-shortening osteotomy without special jigs for ulnar impaction syndrome. Materials and Methods: A retrospective review was performed of 164 consecutive patients who underwent step-cut ulnar-shortening osteotomy between 2000 and 2010. Eighty-eight patients were female and 76 were male with a mean age of 36.8 years. Idiopathic ulnar impaction syndrome was diagnosed in 116 patients, while a posttraumatic etiology was seen in 48 patients. The step-cut osteotomy had its long arm oriented in the coronal plane parallel to the long axis of the ulna. The short arms of the osteotomy were perpendicular to the long axis in the axial plane. Fixation was performed with a palmar 3.5 mm standard neutralization plate and a lag screw. The goal of the osteotomy was to reduce ulnar variance by shortening the ulna 2 to 3 mm and not to create neutral variance. Ulnar variance was assessed radiographically preoperatively and postoperatively with the pronated grip view in all patients. The preoperative ulnar variance ranged from +1 mm to +6 mm. Results: Mean follow-up was 62.4 months (24-86 months). Union of the osteotomy was achieved with a mean of 8.2 weeks. The union rate was 98.78%. There were 2 cases of nonunion, which required additional surgery. The mean postoperative ulnar variance was +0.2 mm (range, −1 mm to +1.5 mm) after a mean overall shortening of 2.5 mm. Modified Mayo Wrist Scores improved significantly from a mean of 47.3 (25-65) preoperatively to 88.8 (60-100) postoperatively. All patients returned to their work in a mean of 4 months. Hardware removal was performed in 12 patients (7.3%) due to plate-related symptoms. No other complications were encountered. Conclusions: The step-cut ulnar-shortening osteotomy provides ample bone-to-bone contact and simplifies control of rotation. Stable internal fixation with standard techniques allowed early return to functional activities. Palmar placement of the plate diminishes the need for plate removal caused by irritation. The step-cut ulnar-shortening osteotomy is a simple and cost-effective technique for ulnar-shortening without the use of special instrumentation in patients with ulnar impaction syndrome.
