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In order to obtain an early prediction for segmental collapse of the femoral head after femoral neck fracture, we have studied in 53 cases of the femoral neck fracture using 99mTC-MDP scintimetry. According to the radionuclide uptake ratio of the femoral heads, we can estimate the gravity of the avascular necrosis of the femoral head after fracture and recognize the repair process in the necrotic head. Fifty-three cases of fresh fracture were examined by sequential scintigraphy before operation and during follow up examinations after operation. The radionuclide uptake were all increased in 3 to 4 months after operation as comparing with that done before operation. The uptake ratios in 37 cases decreased gradually and approached 1 in 12 months after operation. All of them have an excellent result during follow up examination 36 months after surgery. The uptake ratios in 19 cases were also increased after operation, but still maintained at a high level in 6 to 12 months. They all showed radiographical signs of segmental collapse 18 to 24 months after operation. These results showed that uptake ratio of the radionuclide bone imaging is able to predict the occurrence of segmental collapse of the femoral head after femoral neck fracture. The time of the diagnosis by scintigraphy for segmental collapse of the femoral head is earlier than that by radiography.

Necrosis of the head of the femur with segmentary collapse after transcervical fractures occurs in 30 to 50% of the cases. Diagnosis of avascular necrosis should be made early before the head collapses. In a clinical and experimental study, we attempted to perform early screening for this complication. We studied 41 fractures of the neck of the femur with technitium scintigraphy with intravenous injections and compared uptake in pathological and normal heads. In the first group of 20 cases of fresh fractures, scintigraphy was performed before operation then repeated every three months to the 36th months later. High uptake we seen in 12 of the 20 cases then returned to normal 12 to 18 months later. Consolidation occurred in all 12 without necrosis. In 8 cases uptake was low initially then rose greatly and remained higher than normal. Necrosis occurred in 6 of these 8 cases. In a second group of 21 patients with a history of necrosis of the head of the femur, uptake was high. Pathologic examination of the surgical specimen after resection for prosthesis showed cell growth around the zone of necrosis. In conclusion, this technique, when possible, would appear to be highly useful to screen for necrosis early.