Distal Ulna Fracture With Delayed Ulnar Nerve Palsy in a Baseball Player
We present a case report of a college baseball player who sustained a blunt-trauma, distal-third ulna fracture from a thrown ball with delayed presentation of ulnar nerve palsy. Even after his ulna fracture had healed, the nerve injury made it difficult for the athlete to control a baseball while throwing, resulting in a delayed return to full baseball activity for 3 to 4 months. He had almost complete nerve recovery by 6 months after his injury and complete nerve recovery by 1 year after his injury.
Nerve injuries can be classified as neurapraxia, axonotmesis, or neurotmesis. Neurapraxia is the mildest form of nerve injury and neurotmesis the most severe. Neurapraxia may be associated with a temporary block to conduction or nerve demyelination without axonal disruption. Spontaneous recovery takes 2 weeks to 2 months. Axonotmesis involves an actual loss of axonal continuity; however, connective tissue supporting structures remain intact and allow axonal regeneration. Finally, neurotmesis is transection of the peripheral nerve, and spontaneous regeneration is not possible. The mechanism of injury in our patient suggests that the pathology was neurapraxia.1,15
Management of these injuries should proceed according to basic extremity injury–care practices. Initial care should include thorough neurovascular and radiographic evaluations. If nerve deficits are present with a closed injury and minimal fracture displacement, treatment can include observation and serial examinations with a baseline EMG, or waiting until 4 to 6 weeks after injury to obtain an EMG if there are no signs of nerve recovery. Early EMG testing and surgical exploration may be warranted if there is a concern for nerve disruption or entrapment, such as marked fracture displacement or an open injury. Additional early-care measures should include swelling control modalities and immobilization based on the type of fracture. Ultrasound was not readily available at the time of our patient’s injury, but it may be a helpful adjunct in guiding decision-making regarding whether to perform early surgical exploration for hematoma evacuation or nerve injury.16-18 Our case report was intended to provide an awareness of the unusual association between an isolated ulnar shaft fracture and a delayed ulnar nerve palsy in an athlete. Nerve injuries may be unrecognized in some patients in a trauma situation, since the focus is usually on the fracture and the typical patient does not have to return to high-demand, coordinated athletic activity, such as throwing a ball. Because of the possible delayed presentation of these nerve injuries, close observation of nerve function after ulna fractures from blunt trauma is warranted.
