[Changes of the femoral head in intracapsular fractures of the femoral neck---with special reference to old fracture cases].

Coronal slab sections of 78 femoral heads removed from patients with fractures of the proximal end of the femur were examined by radiographical and histological methods and a classification of fracture types based on the epiphysial scar holding an anatomical landmark was presented. The transepiphysial type (type I) showed total necrosis, and in the subepiphysial type (type II) some new bone formation was found at the "subepiphysial" zone, though no such reactive changes were seen in most parts of the specimens. Although necrosis was observed in different degrees and extent in the subcapital type (type III), some reactive new bone formation was always observed in the vicinity of the fracture surface. In the type III which was most frequent, viabilities of the trabeculae were examined in cases of fresh and old fractures (over one month after fractures), with or without internal fixation in old cases. It was then found that bone viabilities were remarkable in the fresh head than the old, and the head excised for failed internal fixation proved to be more viable than the head for primary insertion of a prosthesis. In about a half to one third of the type III the inferior metaphysial vessels were spared. Considering the types of fractures with post-fracture course, the initial type III may be changed into types I, II or III and the initial type II can remain as it is or be transformed into type I.