Heel pain syndrome: electrodiagnostic support for nerve entrapment.

A local entrapment neuropathy has been proposed as one of the etiologies of heel pain, but it has never been documented by electrodiagnostic studies. Primary symptoms in patients suspected of having a neurologic basis for their heel pain include neuritic medial heel pain and radiation either proximally or distally. On physical examination, all patients in our series had reproduction of their symptomatology with palpation over the proximal aspect of the abductor hallucis and/or the origin of the plantar fascia from the medial tubercle of the calcaneus. Twenty-seven patients (20 women and seven men; average age 49) with these clinical characteristics were examined by electromyography and motor/sensory/mixed nerve conduction studies. Bilateral heel signs and symptoms were present in 11 patients. Ten of the patients had a significant history of back pain with referral to the legs. In 23 of the 38 symptomatic heels, abnormalities were identified in the lateral and/or the medial plantar nerves. The number of abnormal values per heel ranged from one to four, with a mean of 2.1. The most common finding was involvement of the medial nerve (57%). Thirty percent of the heels had isolated findings in the lateral plantar nerve and 13% had abnormalities in both plantar nerves. Two patients had electrophysiologic evidence of active S1 radiculopathy, with ipsilateral evidence of plantar nerve entrapment suggesting a "double crush" syndrome. The results of this study support the presence of abnormalities of plantar nerve function in a selected group of patients with neuritic heel pain.