Entrapment of the Posterior Interosseous Nerve

Abstract

48 patients, 20 men and 28 women, were examined because of pain radially-proximally in the forearm, in 2 patients bilaterally. 31 patients, representing 32 elbows, had previously been treated for chronic lateral epicondylitis with local steroid injections, antiphlogistic drugs, immobilization and/or surgery one or several times, without any relief of the symptoms. The affected arm was in 44 instances the most loaded one during work. The duration of the symptoms varied from 6 months to about 10 years, on average 2 years. The main complaint was pain at night, which was reported by 43 patients. Other complaints were pain during work, radiating pain, numbness, and weakness. The main preoperative findings were intense local tenderness about 5 cm distal to the lateral epicondyle, present in all 50 forearms, and indirect pain induced by supination against resistance, present in 43 forearms. The complaints were interpreted as being caused by entrapment of the posterior interosseous nerve at its entrance into the supinator muscle. Decompression of the nerve was performed in all instances. The length of follow-up varied from about 2 months to 3 years, on average 2 years. Results: excellent 33, good 9, fair 6 and poor 2. The preoperative symptoms and findings are discussed, as well as the site and severity of nerve entrapment and the main differential diagnosis: lateral epicondylitis.