[Lesions of the extensor muscles of the knee caused by meniscus injury].

The damage of the knee extensors was examined with integrated EMG and with histochemical and electron microscopical methods in 23 patients with meniscal injury. The integrated DMG has proved in 2/3 of the patients tonic, in 1/3 both tonic and phasic damage of the muscle function. With histochemical examination the decrease of the ratio of the fibers of type 1 was found and also the atrophy of the same fibre type cells in 18-36 per cent. Ultrastructural examinations have shown out of the damage of the contractive elements an increase of the interstitial connective tissue together with alterations of the arterioles in the knee extensors following meniscal injuries.