Prognostic accuracy of preoperative and postoperative scintimetry after femoral neck fracture

Forty patients with fresh femoral neck fractures treated with closed reduction and internal fixation were included in a prospective study of nonunion and osteonecrosis by preoperative and postoperative scintimetry. Correlated roentgenographic follow-up studies were continued for two years postoperatively. The aim of the study was to determine the relative prognostic accuracy of preoperative versus postoperative scintimetry. A ratio between the radionuclide uptake over the femoral head on the fracture side and the contralateral side exceeding 1.9 at the preoperative scintimetry and 1.2 at the postoperative scintimetry was associated with a high incidence of union, whereas a lower ratio often predicted subsequent complications (redisplacement, nonunion, or late segmental collapse). Prognostic accuracy was higher for scintimetry of fractures treated with closed reduction and internal fixation (0.70) than for untreated fractures (0.53). These results suggest that scintimetry is useful postoperatively to complement roentgenographic examination in assessing the prognosis of femoral neck fractures.