INSERTION TENDOPATHY IN ATHLETES - A LIGHT MICROSCOPIC, HISTOCHEMICAL AND ELECTRON-MICROSCOPIC EXAMINATION

Tendon tissue of 11 athletes suffering from insertion tendopathy and of 2 controls was examined. Part of the tissue was prepared for routine light microscopy, a part for enzyme histochemical staining of NADP-diaphorase, lactatedehydrogenase (LDH), .beta.-glucuronidase and alkaline phosphatase. Small pieces of tissue were also prepared for EM examination. The removed tissue was edematous and mushy. The normally densely packed parallel or interwoven collagen bundles were loosened by edema, focal necrosis or hemorrhage. Infiltration of fatty tissue and granulation tissue was also present. The amount of acid mucopolysaccharides was markedly increased. The histochemical studies showed strong enzyme activity of NADP-diaphorase and LDH in normal tendon tissue as well as around areas of degeneration and in granulation tissue. .beta.-Glcuronidase and alkaline phosphatase was present, but in general with lesser activity than the above enzymes. The EM examination revealed marked degeneration of the fiber systems, focal necrosis, deposit of amorphous masses and mucopolysaccharides and focal mineralization. The reparative zones showed proliferating capillaries, often with a collapsed lumen and prominent endothelial cells and basement membranes.