Ulnar nerve palsy associated with closed midshaft forearm fractures.

Ulnar nerve palsy is a rare complication of closed midshaft forearm fractures; only 8 cases have been reported. This article describes a case of ulnar nerve palsy associated with a midshaft forearm fracture. A 12-year-old girl sustained a right midshaft forearm fracture. Whether she had a peripheral nerve injury was unknown due to strong pain. She underwent emergency manual reduction and intramedullary pinning. However, ulnar nerve palsy was remarkable postoperatively and gradually worsened. Therefore, neurolysis was performed 9 weeks later. The nerve had adhered to surrounding scar tissue. Six months after a second surgery, she had no motor dysfunction. The pathogenesis of ulnar nerve palsy complicated with midshaft forearm fractures varies and may be the result of direct contusion, direct damage by a bony spike, bony entrapment after closed reduction, and entrapment by a scar. In the current case, the patient was uncooperative at initial examination. Therefore, it is unknown whether she presented with immediate ulnar nerve palsy after the fracture. However, the ulnar nerve was not entrapped at the fracture site, and the surrounding muscle was intact but adhered to the surrounding scar tissue. The etiology of this case was considered to be entrapment by scar formation. According to a literature search, the authors recommend exploring the nerve approximately 8 to 10 weeks after primary surgery, after which neurological symptoms do not tend to improve.