Thirty-nine patients with a clinical diagnosis of the pronator teres
syndrome were seen during a seven-year period. They typically complained of
aching discomfort in the forearm, weakness in the hand, and numbness in the
thumb and index finger. Cyclic stress usually brought on the symptoms. The
distinctive physical finding was tenderness over the proximal part of the
pronator teres, which was aggravated by resisted pronation of the forearm,
flexion of the elbow, and occasionally by resisted contraction of the
flexor superficialis of the long finger. Electrophysiological testing of
the median nerve showed abnormalities in a few patients, but localization
of the abnormality was possible only rarely. Intraoperative recordings
showed some improvement shortly after release of the median nerve in six of
the ten forearms that were tested. Surgical exploration of thirty-six
forearms in thirty-two patients showed intramuscular tendinous bands in the
pronator, indentation of the muscle belly of the flexor superficialis in
most forearms. Vascular and muscular abnormalities were seen occasionally.
Of the thirty-six operations, twenty-eight gave good or excellent results;
five, fair; and in three patients the symptoms were unchanged. The cause of
failure was either inadequate decompression or misdiagnosis.