Ulnar nerve injury following K-wire fixation of supracondylar humeral fracture in a child with ulnar nerve Instability: case report and review of literature

Iatrogenic ulnar nerve damage is not uncommon following Kirschner-wire (K-wire) fixation of supracondylar humeral fractures in pediatric patients. The risk of injury may be increased when the ulnar nerve is hypermobile. We report a 7-year-old boy who had a Gartland type IIb supracondylar fracture of the right humerus, treated with closed reduction and crossed K-wire fixation. The ulnar nerve was not detectable within the cubital tunnel but could be felt as a cord-like structure in front of the medial epicondyle. Immediately after surgery, the patient developed excruciating, incomplete clawing and paresthesia of the ring and little fingers. A surgical exploration performed the following day showed the ulnar nerve positioned anterior to the medial epicondyle, tented over the K-wire. The K-wire was removed, and one more lateral pin was inserted with nerve decompression. Complete recovery of nerve injury was noticed four weeks after exploration. Given the greater prevalence of ulnar nerve instability among children, it is prudent to preoperatively evaluate patients for evidence of ligament laxity or ulnar nerve instability of the contralateral normal elbow. Prompt exploration and K-wire removal can confirm nerve continuity, reassure the family, and ensure swift recovery from nerve injury.