Abstract
BackgroundsOne of the most significant complications after a femoral neck fracture is osteonecrosis of the femoral head (ONFH). The concomitant use of single-photon emission computed tomography (SPECT) with computed tomography (CT) increases the sensitivity for detecting the anatomic location and severity of ONFH. In this study, we evaluated the diagnostic value of SPECT/CT for the occurrence of ONFH by quantifying the perfusion status of the femoral head.MethodsA total of 30 patients who had multiple pinnings for femur neck fractures were included in this study. We classified the perfusion status into three groups: normal perfusion, decreased perfusion, and avascular groups, and compared the occurrence of femoral head necrosis between them. For quantitative analysis, we evaluated the uptake ratio of both femur heads (head-to-head uptake ratio). If the patient’s contralateral hip was incomparable, we measured the uptake ratio from the superior dome of the ipsilateral acetabulum (head-to-acetabulum uptake ratio).ResultsTwenty-four patients out of 30 achieved bone union, whereas the others developed ONFH. When the population was divided into intact and defective perfusion groups on scintigraphy, the sensitivity, specificity, and accuracy of the test were 83.3, 75.0, and 76.7%, respectively. The mean head-to-head uptake ratio value with a 95% confidence interval (CI) was 1.10 (95% CI: 0.85–1.36). In the osteonecrosis group, the mean value of the head-to-head uptake ratio was 0.33 (95% CI: 0.28–0.38). In contrast, the ratio was 1.30 (95% CI: 1.03–1.57) in the non-osteonecrosis group, demonstrating a significant difference in the uptake ratio (P < 0.001). When the cutoff value of the uptake ratio was set to 0.5, both the sensitivity and specificity were 100%. There was also a significant difference in the head-to-acetabulum uptake ratio between the two groups (P < 0.001).ConclusionsSPECT/CT was useful in evaluating the perfusion status of the femoral head, showing high accuracy in predicting the occurrence of avascular necrosis. To demonstrate the reliability and validity of SPECT/CT, further prospective studies on a larger scale are warranted.
Highlights
The incidence of femoral neck fractures (FNFs) is increasing as the number of elderly people increases
Several studies reported the incidence of osteonecrosis of the femur head (ONFH) after the osteosynthesis of FNF to be 12.0–17.3% [7, 10]
The exact evaluation of the perfusion status of the femoral head after FNF is critical in predicting the risk of ONFH so that it could guide a surgeon to select the optimal treatment modalities to lower the complication rate and achieve a favorable outcome
Summary
The incidence of femoral neck fractures (FNFs) is increasing as the number of elderly people increases. The surgical treatment of FNF includes osteosynthesis or arthroplasty, which can be selected based on the displacement of fracture or the age of the patient [4,5,6,7,8,9]. Several studies reported the incidence of osteonecrosis of the femur head (ONFH) after the osteosynthesis of FNF to be 12.0–17.3% [7, 10]. The exact evaluation of the perfusion status of the femoral head after FNF is critical in predicting the risk of ONFH so that it could guide a surgeon to select the optimal treatment modalities to lower the complication rate and achieve a favorable outcome. Most of the study results are based on qualitative measurements. The two-dimensionally reconstructed three-dimensional anatomical structure is likely to produce false-negative results due to overlying structures
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