External and biopsy determination of preoperative Tc-99m MDP femoral-head labeling in fracture of the femoral neck: concise communication.

In 30 fresh fractures of the femoral neck, the preoperative femoral-head tracer uptake in Tc-99m MDP scintimetry was compared with the uptake of peroperatively obtained femoral-head biopsies and correlated to intravital bone staining by tetracycline, infused concurrently. Bone uptakes of Tc-99m MDP and tetracycline were shown to correlate well. Total absence of Tc-99m MDP uptake in the femoral-head biopsy corresponded to a scintigraphic uptake ratio of 0.7 (fractured over contralateral head), whereas a normal Tc-99m MDP biopsy uptake corresponded to a ratio of 1.5. This suggests that in Tc-99m MDP scintimetry of a normal hip, less than half of the emission ascribed to the femoral head is derived from the femoral head itself.