Ulnar Shortening for Adolescent Ulnar Impaction Syndrome: Radiological and Clinical Outcomes

Abstract

To determine the amount of shortening needed in an ulna to achieve final neutral ulnar variance in adolescents with ulnar impaction syndrome. Radiological and clinical outcomes were evaluated after ulnar shortening and after growth had stopped. From February 2006 to February 2009, we prospectively followed 16 consecutive patients treated with a shortening osteotomy for positive ulnar variance. The study group included 10 boys and 6 girls with an average age of 16.1 years. The closed medial half-side of the physis of the distal radius was used to measure the variance as a reference for the ulna. Based on the radius without any growth potential, the amount of shortening was determined for the ulna with potential for further growth. The preoperative, postoperative, and final ulnar variances were evaluated. The clinical results were compared before surgery and at the time of growth termination. Preoperative ulnar variance was 3.4 mm ± 0.6 mm and the amount to be shortened was 6.1 mm ± 1 mm. The final ulnar variance was 0.2 mm ± 0.3 mm. The mean visual analog scale pain score improved from 6.6 ± 1.0 before surgery to 2.2 ± 0.5 after surgery. The mean range of forearm rotation increased from 132° ± 11° before surgery to 170° ± 16° at final follow-up. In addition, grip strength was 15.3 kg ± 7.6 kg (71% of grip strength on the unaffected side) before surgery and 19.8 kg ± 4.9 kg (90% of grip strength on the unaffected side) at final follow-up. The modified Mayo Wrist Score was 85 ± 8 at the final follow-up. No cases of complications or treatment failure occurred. Ulnar shortening was considered a useful procedure for adolescents with ulnar impaction syndrome, particularly if the measurement for the shortening amount was determined using the physis of the distal radius and ulna.