The predictive value of bone scintigraphy after internal fixation of femoral neck fractures

Abstract

Persisting pain of the hip following internal fixation of fracture of the neck of the femur is often caused by capital necrosis or non-union. In a randomized trial 35 patients had 99mTc-MDP bone scintigraphy performed 6 weeks, 3, 6, and 12 months after internal fixation of their subcapital fractures with a sliding screw-plate or a sliding nail-plate. The purpose was to find out whether bone scintigraphy could predict capital necrosis or non-union before it shows up on plain radiographs, which happens later. The patients were followed up for an average of 44 months (range 12-64). Radiologically, capital necrosis occurred in five patients and non-union in six. Bone scintigraphy showed decreasing activity in the 1st year after operation in uncomplicated cases (P less than 0.03). However, it was impossible to distinguish patients with capital necrosis or non union from those with uneventful healing. There were no significant differences in the scintigraphic appearance between groups at most risk, e.g. Garden stage 3 and 4 fractures versus Garden stage 1 and 2, and fixation by sliding nail versus fixation by sliding screw-plate. In conclusion, bone scintigrams during the first 6 months after operation do not reliably predict failure of internal fixation of fractures of the neck of the femur.