Posterior interosseous nerve neuropathy. Clinical and electromyographical aspects

A clinical-EMGraphic examination was carried out in 37 patients with posterior interosseous nerve neuropathy: 5 cases had a traumatic origin, 4 iatrogenic, and 28 non-traumatic. One of the non-traumatic cases had a lipoma, and another had chondroma. In the other cases, nerve entrapment at the level of the arcade of Frohse could be presumed. Acute or chronic onset of the deficit was probably due to repeated pronation-supination hand movements. A motor deficit in finger extension together with a radial deviation of the wrist, was typical. Surprisingly about 50% of the non-traumatic cases showed some sensory disturbance at the forearm, wrist or hand. EMG examination was useful to establish the entity and topography of the deficit. Follow-up was carried out in 27 cases (3 traumatic, 2 iatrogenic and 22 non-traumatic). Even if spontaneous recovery is possible, though infrequent, in non-traumatic cases with marked deficit surgery gave the most satisfactory results, especially when onset had been acute and operation was performed within nine months of onset.