[Morphological and biochemical changes in the pars obliqua of the vastus medialis muscle in degenerative disorders of the knee joint].

Using 34 muscle specimens from the pars obliqua of the vastus medialis muscle of patients with a clinically manifest patellar chondropathy and of those suffering from a gonarthrosis in various positions (cut biopsies under operation), we depicted the slow-twitch (ST) and the fast-twitch (FT) fibres histochemically and ascertained morphometrically the fibre distribution, the areas of the FT- and the ST-fibres as well as the relative fibre volume of the FT-fibres. Furthermore, we determined biochemically the total activity of the enzymes PGK and of the MDH, according to Bergmeyer (1970). By means of the electrophoresis, we determined the isoenzyme pattern of the LDH from simultaneously cut material (Agar-Agarose technique). The mathematical date processing was made by means of the cluster- und discriminance analysis. The results show that the "rule member" (pars obliqua m. vast. med.)--in order to maintain the orthograde gliding motion of the patella in the course of the development of degenerative joint illness--experiences extreme structural and biochemical changes caused by modifications within the neuromuscular motor control pattern. This becomes evident by a FT-hypertrophy at the beginning of the intraarticular disorders and by the increasing development of the "neurogeneous tissue syndrome" with partly fascicular FT-atrophy in cases of progressive degenerative joint processes.