Prediction of fixation failure in femoral neck fractures. Comminution and avascularity studied in 40 patients.

We performed 99m-Tc diphosphonate scintimetries in 40 elderly patients who had undergone screw fixation for a recent subcapital femoral fracture and analyzed their preoperative radiographs. The data were subjected to a logistic regression analysis. Both comminuting of the calcar femorale and reduced scintimetric uptake were predictive for failure of the osteosynthesis during the first year. Fracture comminution was more predictive for early failures during 3 months and scintimetry for the later failures.