Radionuclide scintimetry for diagnosis of complications following femoral neck fracture

A scintimetric study using Tc-99m MDP was made of 54 patients with delayed union, nonunion, or late segmental collapse of the femoral head, 4-92 months after femoral neck fracture. In radiographically verified collapse, the radionuclide uptake ratio between the femoral head on the fractured and on the intact side (HHR) was significantly higher than in fractures resulting in delayed union or nonunion. On the basis of scintimetric and radiographic findings, the patients with healing disturbances could be divided into three groups, characterized by the following features: (1) Satisfactory post-reduction position of the fracture without subsequent redisplacement and a high HHR, which as a rule turned out to be delayed union; (2) The same radiographic pattern but with a lower HHR, which in most cases resulted in nonunion; (3) Inadequate reduction or early rediaplacement of the fracture with a high HHR, which resulted in nonunion. The fractional precision in discriminating between different types of disturbed fracture healing by means of skeletal scintimetry was 0.86 in this study. This non-invasive and technically simple method would therefore be a valuable complement to radiography in the assessment of healing, more than 4 months after fracture of the femoral neck.