脆性股骨颈骨折的股骨颈皮质厚度和骨密度改变

目的 研究脆性股骨颈骨折的股骨颈皮质骨厚度和骨密度变化。方法 对76例病人行股骨近端CT扫描，骨质疏松性股骨颈骨折组42 例，非骨折组34 例。取对侧（正常侧）股骨小转子顶点上方20mm（T20）平面CT横截面影像，计算T20长径和股骨颈寛径皮质比率，作为评估皮质厚度的指标；用DXA测量股骨颈骨密度，了解骨质疏松程度。结果 T20长径皮质比率：骨质疏松性股骨颈骨折组：（17.57±3.54）% ；非骨折组：（21.64±3.75）%（P =0.000）；T20股骨颈宽径皮质比率：骨质疏松性股骨颈骨折组：（25.98±5.51）%；非骨折组：(32.89±5.74)%（P=0.000）。骨密度：骨折组：0.590±0.084 g/cm2 ；非骨折组：0.698±0.138g/cm2， , P <0.000。结论 股骨颈皮质变薄和骨密度降低是导致脆性股骨颈骨折重要因素，T20长径皮质比率和T20股骨颈宽径皮质比率是观察股骨颈皮质骨变化的有效指标。

Changes of the cortical thickness and BMD of the femoral neck in fragile femoral neck fractures

Objective To study the changes of the cortical thickness of the femoral neck in fragile femoral neck fractures. Methods The CT scan of the proximal femur in 76 patients was performed. Forty-two patients with had osteoporotic femoral neck fractures, including 12 males and 30 females, with an average age of 74.4±9.3 yrs. Thirty-four patients, including 12 males and 22 females, were in non-fracture group, with an average age of 63.3±9.3 yrs. The parameters were defined from the CT films at T20 level (the neck at 20 mm higher than the apex of lesser trochanter) in the contralateral (normal side) hip. The cortex ratio of T20 long diameter and the cortex ratio of wide diameter of the neck at T20 were calculated for the evaluation of the changes of the cortical thickness of the femoral neck. BMD of the femoral neck was detected using DXA to evaluate the severity of osteoporosis. Results The cortex ratio of T20 long diameter in the fracture group and non-fracture group was 17.57±3.54% and 21.64±3.75%, respectively (P =0.000). The cortex ratio of wide diameter of the neck at T20 in the fracture group and non-fracture group was 25.98±5.51 % and 32.89±5.74%, respectively (P =0.000). BMD of the femoral neck in the fracture group and the non-fracture group was 0.590±0.084 g/cm2 and 0.698±0.138g/cm2, respectively (P<0.000). Conclusion The thinned cortex and decreased BMD of the femoral neck are the main factors leading to fragile femoral neck fractures. The cortex ratio of T20 long diameter and wide diameter of neck at T20 is effective index to evaluate the changes of the femoral neck cortex.