ROTATOR CUFF DEGENERATION AND LATERAL EPICONDYLITIS - A COMPARATIVE HISTOLOGICAL STUDY

Objectives-Rotator cuff tendinitis and lateral epicondylitis are commo n in clinical practice but the underlying pathology is poorly understo od. The study examined both normal and biopsy tendon specimens histolo gically, to determine the mechanisms involved in tendon degeneration. Methods-Rotator cuff tendons from 83 cadavers aged 11-94 and tendon bi opsy specimens from 20 patients with lateral epicondylitis aged 27-56 years were examined histologically. Results-The microscopic changes fo und in the tendon biopsies from the elbow were similar to those found in the cadaveric rotator cuff tendons. Abnormalities ranged from minor blood vessel wall changes and loss of tenocytes to calcification. The most frequent abnormality was glycosaminoglycan infiltration and fibr ocartilaginous transformation. There appeared to be some sequence in t he changes observed which were milder in younger patients. Only 17% of cadaver tendons, below the age of 39 were abnormal but abnormalities increase in later life to around 40-50%. Conclusions-There was an incr easing incidence of degenerative changes in tendons with age. The chan ges observed in biopsy samples of common extensor tendons were the sam e as those seen in aged supraspinatus tendons, but these changes were not seen in control common extensor tendons.