Fracture of the femoral neck. II. Relative importance of primary vascular damage and surgical procedure for the development of necrosis of the femoral head.

The opinion is widely held that interruption of the arterial flow through the retinacular arteries to the femoral head is the main cause of avascular necrosis after fracture of the neck. In this study the state of the vascular supply to the femoral head was assessed--prior to osteosynthesis--by means of intramedullary pressure measurements in the femoral head and neck in 72 patients with medial neck fractures. The patients were followed 2 or 3 years or until avascular necrosis became evident. The relative importance of primary avascularity and surgical technique for the development of necrosis suggests that damage to the retinacular arteries may not be the single decisive factor in the pathogenesis of femoral head necrosis. Proper fracture reduction with extensive contact between the cancellous bone surfaces and stable fixation seemed to be more important, probably because they offer the best possibilities for re-establishment of transosseous blood flow across the fracture site.