Department of Orthopaedic Surgery, Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, Japan.
J Bone Joint Surg Am. 2022 Apr 6;104(Suppl 2):33-39. doi: 10.2106/JBJS.20.00493.
Little is known concerning differences in assessment of anteroposterior osteonecrotic lesion of the femoral head (ONFH) between the axial plane parallel to the body axis (axial) and the axial plane parallel to the femoral neck axis (oblique axial) using magnetic resonance imaging (MRI). This study aimed to compare the posterior boundary of necrotic lesions between the axial and oblique axial planes on MRI.
This study retrospectively reviewed 120 consecutive hips in 71 patients (47 males and 24 females; mean age, 42 years) with ONFH, for which both axial and oblique axial MRI slices were available. The posterior boundaries of the necrotic lesions were calculated as the ratio of posterior intact circumference to anteroposterior circumference of the femoral head using mid-axial and mid-oblique axial MRI slices. The necrotic angles, calculated using the modified Kerboul method, were compared between cases with progression and nonprogression of collapse.
The mean posterior intact ratio in the axial slice was 49.2% (range, 8.6 to 85.1%), while that in the oblique axial slice was 33.5% (7.5 to 79.2%). The posterior intact ratio in the oblique axial slice significantly decreased compared to that in the axial slice (p < 0.0001). In cases with progression of collapse, the mean necrotic angle was significantly larger in the oblique axial slice than in the axial slice (p < 0.0001). The sensitivity and specificity of the necrotic angle with regard to the prognosis of the femoral head were both higher when using the oblique axial slice (sensitivity: 88.4%, specificity: 82.3%) than when using the axial slice (sensitivity: 85.1%, specificity: 62.0%). The posterior intact ratio at a mean of 6.8 mm superior to the mid-axial slice corresponded to that of the mid-oblique axial slice.
Our findings suggest that the posterior boundaries of necrotic lesions differ between axial and oblique axial slices, and examination of the oblique axial MRI slice might be more suitable for predicting the prognosis of the femoral head.
Diagnostic-Investigating a diagnostic test. Level IV (Case series).
关于在使用磁共振成像（MRI）时，沿身体轴平行的矢状面（轴向）和沿股骨颈轴平行的矢状面（斜矢状面）评估股骨头坏死（ONFH）前后骨坏死病变，人们知之甚少。本研究旨在比较 MRI 上轴向和斜矢状面之间的坏死病变后边界。
本研究回顾性分析了 71 例（47 名男性和 24 名女性；平均年龄 42 岁）120 例连续髋关节 ONFH 患者的资料，这些患者均有轴向和斜矢状面 MRI 切片。使用中轴和中斜轴 MRI 切片计算坏死病变的后边界，计算为股骨头前后周长的后完整周长比。使用改良 Kerboul 法比较了塌陷进展和非进展病例之间的坏死角度。
轴向切片中平均后完整率为 49.2%（范围 8.6%至 85.1%），而斜矢状面切片为 33.5%（7.5%至 79.2%）。斜矢状面的后完整比在轴向切片中显著降低（p<0.0001）。在塌陷进展的病例中，斜矢状面的平均坏死角度明显大于轴向切片（p<0.0001）。斜矢状面的坏死角度对股骨头预后的灵敏度和特异性均高于轴向切片（灵敏度：88.4%，特异性：82.3%）（灵敏度：85.1%，特异性：62.0%）。在中轴切片上方平均 6.8mm 处的后完整率与中斜矢状面切片相对应。
我们的研究结果表明，坏死病变的后边界在轴向和斜矢状面之间存在差异，并且检查斜矢状面 MRI 切片可能更适合预测股骨头的预后。
诊断-研究一种诊断测试。IV 级（病例系列）。
