Posterior Interosseous Nerve Palsy Associated with Radial Neck Nonunion: A Case Report.

Posterior interosseous nerve palsy can occur from fractures1,2, tumors that compress the nerve against anatomic structures such as the arcade of Frohse3-8, radial osteomyelitis9, or Monteggia fracture-dislocation10,11. Patients with posterior interosseous nerve palsy typically present with weakness of wrist and finger extension. We describe a patient who presented with a posterior interosseous nerve palsy that occurred in the presence of a radial neck fibrous nonunion. To our knowledge, no similar cases have been previously described. The purpose of this case report is to raise awareness of another etiology for posterior interosseous nerve palsy. The patient was informed that data concerning the case would be submitted for publication, and she provided consent. A seventy-year-old right-hand-dominant woman initially presented with elbow pain two weeks after a fall on her outstretched left hand. On examination, she had 40° to 125° of elbow motion and full forearm rotation. While the radial head and neck were tender to palpation, there was no crepitus with elbow flexion/extension or forearm rotation. In addition to a normal wrist examination, the neurovascular examination also was completely normal. Radiographs revealed a minimally displaced radial neck fracture with a nondisplaced intra-articular extension into the radial head (Fig. 1). Given the acceptable fracture alignment on radiographs, the arm was treated nonoperatively with a sling and active elbow motion. At four months postinjury, she was asymptomatic …