[Pathogenesis of quadriceps contracture in children and adolescence (author's transl)].

Forty-one limbs in 35 patients were examined about the findings concerning with quadriceps contracture at operation and moreover pathohistological examination was carried out for the whole length of the resected rectus femoris muscle in every patient in order to study pathogenesis of contracture of the quadriceps muscles. The age of patients at operation was two years and 3 months for the youngest and 17 years and 3 months for the oldest. Among these patients, the previous history of injection was positive in 29 cases, negative in 5 cases and unknown in one case. In cases with nor previous history of injection, the cross sections of the rectus femoris muscle macroscopically revealed that scar exists over the whole length of this muscle, showing clear boundary between scar and adjacent muscles. Pathohistological examination showed that fibrosis of the muscle fibers in addition to infiltration of fibrous tissues between muscle fibers. On the other hand, in cases with previous history of injection, pathohistological findings revealed that atrophy and degeneration were marked in the whole area of the muscle fibers in comparison with non-injection cases although scar in muscle was not so clear macroscopically. As the operative findings in the cases with or without injection in the previous history, considerable adhesion and scar were seen in the muscles and fascias surrounding the rectus femoris muscle. Therefore, in order to release contracture it was necessary to detach these adhesions, to remove scar tissues and to cut the contracted fascia. From these results, it is considered that the chief cause for the contracture of the quadriceps muscles treated by us can be attributable to the muscles showing contracture over the whole length and lacking normal elasticty, which produce adhesions caused in scar formation with surrounding muscles and fascias. The various clinical symptoms associated with quadriceps contracture depend upon the severity of such pathologic changes. The follow-up results obtained in these cases were to be satisfied. Therefore, the findings at operation, pathohistological findings, operative technique and follow-up results in our cases are fully justified in recommending our method. However, it was impossible to classify clearly our cases into rectus type, vastus type or mixed type according to the general criteria. In other words, all of our cases could be classified into mixed type. It may be explained by small number of cases as well as 41 limbs included in our study.