Stenosing tenosynovitis of the pseudosheath of the tendo Achilles.

This entity consists of a chronic inflammatory process of peritenon of the tendo Achilles (usually bilateral) at variable points of the tendon itself but usually near the insertion in the Achilles. Its occurrence, but not only in runners but in relatively sedentary individuals of both sexes, seems to be the result of microtrauma of stress with insidious onset of local pain in increasing degree with physical activity. Clinically, in the advanced cases, fibrillation, nodulation, and "yellowing" of the edematous tendon occur and probably are a precursor to later ruptures. Pathological changes consist of one or more of the following: a myxomatous degeneration of collagenous tissue; fibrosis; round cell inflammatory infiltrate; and proliferation of fibrovascular connective tissue. The use of steroid injections seems to be of no help and probably is contraindicated. Surgery consists of excision of the entire pseudosheath, allowing the tendon to assume a new, nonconstricting alignment. All but one of the nine patients with a follow-up of at least 1 year went on to clinical, painless recovery, with unrestricted future activity, in just a few months.