342 achilles tendons in 298 patients were operated on for painful chronic achilles tendinopathy (81% men; mean age 35 (18-82) years; 79% athletes). A partial rupture was found in 23%, tendinosis (degeneration) in 49% and no macroscopic pathology in 28% of the tendons. In partial ruptures, as compared with non-ruptured tendons, the lesion was commoner in the distal part of the tendon and more frequent in physically active men slightly below middle age who had received local steroid injections before surgery. In a logistic regression analyzing age, gender, physical activity and preoperative steroid injections, only preoperative steroid injections and male gender predicted a partial rupture.