沿股骨转子间线环周皮质的CT影像学测量及临床意义

Clinical implications of 3D-CT measurement of oblique circumferential cortex along the intertrochanteric line

关键词:  股骨转子间骨折  转子间线  环周皮质  前内侧皮质  皮质支撑复位  CT测量

Key words:  pertrochanteric fracture  intertrochanteric line  circumferential cortex  anteromedial cortex  cortex support reduction  CT measurement

摘要:

目的 探讨沿股骨转子间线环周皮质在CT三维影像上的形态学特征，为股骨转子间骨折的前内侧皮质支撑复位提供理论依据。方法 收集30例年龄>60岁的无股骨骨折既往史的老年人股骨近端CT影像学资料，将数据导入Mimics软件，经三维重建后，沿股骨转子间线的中线截取皮质斜断面，并按钟面将其分割为12等份，其中的第6、7区段为前内下角皮质。测量该斜面环周皮质各区段的厚度、面积、密度，并计算其相对强度的百分比。结果 沿转子间线斜切面，前内下角区段的皮质厚度平均为(12.96±0.59) mm，非前内下角区段平均为(5.80±0.44) mm；前内下角区段的面积平均为(175.58±3.48) mm2，非前内下角区段平均为(84.10±2.44) mm2；前内下角区段的皮质相对强度平均为(392.27±9.35) g/mm，非前内下角区段平均为（145.48±4.51） g/mm。前内下角区段虽然仅占环周皮质总长度的1/6，但其面积却占整个环周皮质面积的29.46%，占后内侧小转子骨块分离后（即A2型骨折模型）剩余皮质面积的44.72%；其强度则占整个环周皮质总强度的35.04%，占后内侧小转子骨块分离后剩余皮质强度的47.79%。结论 前内下角皮质在厚度、面积、密度和相对强度方面，均高于转子间线的其他区段。前内下角皮质是股骨转子间骨折皮质支撑复位的首选和可靠部位。

Abstract:

Objective To analyze the clinical implications of 3D-CT measurement of oblique circumferential cortex along the intertrochanteric line in treatment of pertrochanteric hip fractures. Methods The CT images of 30 normal femurs of individuals aged >60 years were collected and the three-dimensional reconstruction were made with Mimics software. The oblique intertrochanteric cortical section was intercepted along the intertrochanteric midline, and was divided into 12 equivalent segments by 30-degrees arc. The segments 6 and 7 represented the anteromedial cortical area. The thickness, area and gray value of the circumferential cortex were measured, and the cortical relative intensity was calculated by the density and area. Results The average thickness of the anteromedial cortex(segments 6 and 7) was (12.96±0.59) mm, while that of the rest segments was (5.80±0.44) mm；the average area of the anteromedial cortex was (175.58±3.48) mm2, while that of the rest segments was (84.10±2.44) mm2; the average cortical intensity of the anteromedial cortex was (392.27±9.35) g/mm, while that of the rest segments was (145.48±4.51) g/mm. Although the length of anteromedial cortex accounted only one-sixth of the total length, its area accounted for 29.46% in the normal circumferential cortex, and accounted for up to 44.72% in the type A2 fracture model(separated posteromedial lesser trochanter fragments). The intensity of the anteromedial cortex accounted for 35.04% in the normal circumferential cortex, and accounted for up to 47.79% in the type A2 fracture model. Conclusion The cortex of anteromedial inferior corner is greater than that of the rest parts in terms of thickness, area, density and relative intensity, which indicates that the anteromedial cortex is the strongest part and reliable for cortical support reduction in pertrochanteric hip fractures.