Incidence and severity of femoral head avascularity after femoral neck or intertrochanteric fractures on preoperative bone single photon emission computed tomography/computed tomography: preliminary study.

OBJECTIVE: The aim of the present study was to evaluate the incidence and degree of femoral head avascularity depending on the types of femoral neck or intertrochanteric fractures using preoperative bone single photon emission computed tomography (SPECT)/computed tomography (CT).

PATIENTS AND METHODS: A total of 131 patients with femoral neck or intertrochanteric fractures who underwent preoperative bone SPECT/CT were enrolled. Femoral head avascularity was evaluated using bone SPECT/CT images. Visual scores ranged from 1 to 5 based on visually assessed diagnostic confidence: 1=definitely avascular femoral head, 2=likely avascular, 3=equivocal, 4=likely not avascular, and 5=definitely not avascular. In quantitative analysis, contralateral, ipsilateral, and size ratios were measured.

RESULTS: Among 131 patients, 39 of 54 (72.22%) with femoral neck fractures and 23 of 77 (29.87%) with intertrochanteric fractures showed avascular femoral heads. The incidence of femoral head avascularity was significantly higher in patients with femoral neck fracture than those with intertrochanteric fracture. While the incidence and severity of femoral head avascularity increased with higher Garden stage in femoral neck fracture, neither was related to AO/Orthopaedic Trauma Association classification of intertrochanteric fracture. In addition, the number of bony fragments around intertrochanteric fractures was not a significant predictor of femoral head avascularity.

CONCLUSION: Although avascular femoral head on bone SPECT/CT does not directly indicate avascular necrosis, assessing the incidence and severity of femoral head avascularity using qualitative and quantitative parameters could give clinically useful information related to the classification. Additional studies with larger sample sizes would be a next step to expand the clinical role of bone SPECT/CT.