Peroneal nerve entrapment.

Sixty patients (sixty-two limbs) who had entrapment of the peroneal nerve were managed with operative decompression, and the results were evaluated after an average duration of follow-up of forty-two months (range, twenty-five to 162 months). The entrapment was postural in five patients, dynamic in two (one of whom had bilateral entrapment), and idiopathic in fifty-three (one of whom had bilateral entrapment). Fifty-eight patients (including the two who had bilateral entrapment) had a positive Tinel sign. Twenty-two patients (including the two who had bilateral entrapment) had sensory symptoms only, and thirty-eight had both sensory and motor symptoms. Electrophysiological studies were performed for all patients in order to confirm the diagnosis. Sensory deficits were confirmed on the basis of a marked decrease in the amplitude of sensory potentials, and motor deficits were confirmed on the basis of decreased nerve-conduction velocities. The common peroneal nerve was decompressed by division of both edges of the fibular fibrous arch. The average time from the onset of symptoms to the operation was fourteen months (range, one to 120 months), primarily because of delayed referrals. Twelve of the twenty-two patients who had had only sensory symptoms preoperatively had complete recovery by the time of the latest follow-up. The average delay from the onset of symptoms to the operation was thirty months (range, six to eighty-six months) for the ten patients (eleven limbs) who did not have full recovery compared with nine months (range, four to thirty-six months) for the twelve patients (thirteen limbs) who did. The postoperative recovery of motor function, as determined with use of the grading system of the Medical Research Council, was good for thirty-three (87 per cent) of the thirty-eight patients who had had both sensory and motor symptoms preoperatively. All seven patients who had peroneal nerve entrapment of known etiology had improvement postoperatively. We recommend operative decompression when symptoms persist or recovery remains incomplete for three to four months, provided that the diagnosis has been confirmed with electrophysiological studies.