The Arthroscopic Wafer Procedure Provides Successful Midterm Outcomes for Idiopathic Ulnar Impaction Syndrome: A Minimum 5‐Year Follow‐Up

PURPOSE: To evaluate the midterm clinical and radiologic outcomes of the arthroscopic wafer procedure for idiopathic ulnar impaction syndrome with a minimum 5-year follow-up. METHODS: Patients with idiopathic ulnar impaction syndrome and less than 4 mm of positive ulnar variance who underwent the arthroscopic wafer procedure between May 2009 and February 2017 were analyzed. Only patients with a minimum follow-up of 5 years were included. Clinical outcomes, including the visual analog scale pain score; Mayo Wrist Score; Disabilities of the Arm, Shoulder, and Hand score; grip strength; and range of motion, were assessed. A cohort-specific minimal clinically important difference analysis was performed. Radiographic changes in the distal radioulnar joint (DRUJ) were reviewed, and univariate logistic regression identified prognostic factors for DRUJ changes. RESULTS: Forty patients (10 men, 30 women; mean age, 54.0 years; mean follow-up, 73.3 months) were analyzed. Clinical outcomes improved significantly (all P < .001): visual analog scale (5.5-1.7), Mayo Wrist Score (51.9-86.5), Disabilities of the Arm, Shoulder, and Hand (47.7-14.3), and grip strength (11.7-15.9 kg). Minimal clinically important difference achievement rates were 100% for visual analog scale, 100% for Mayo Wrist Score, 92.5% for Disabilities of the Arm, Shoulder, and Hand, and 55.0% for grip strength. On sex-disaggregated analysis, male patients showed significantly greater grip strength than female patients (19.4 vs 14.7 kg, P = .009), with no other significant differences. One patient required conversion to ulnar shortening osteotomy. No significant complications occurred. Eight patients showed asymptomatic DRUJ arthritis. Preoperative ulnar variance significantly predicted postoperative DRUJ arthritis (odds ratio, 4.393; P = .015). CONCLUSIONS: The arthroscopic wafer procedure showed favorable midterm outcomes at a minimum 5-year follow-up in appropriately selected patients, with high proportions of patients achieving clinically meaningful improvements. Postoperative radiographic DRUJ arthritis was observed in some patients, who remained asymptomatic, and appeared to be associated with greater preoperative ulnar variance. LEVEL OF EVIDENCE: Level IV, retrospective case series.