双能X线骨密度仪在检测全髋股骨头假体周围骨密度的应用

Dual-energy x-ray absorptiometry measurement of bone mineral density around femoral components

目的 寻求检查非骨水泥全髋置换 (THR CL)手术前后骨密度 (BMD)变化的最佳方法。方法 采用双能X线骨密度仪 (DEXA)与常规X线摄片对 7例手术前、后以及术后 1～ 3年内的近段股骨各兴趣区BMD进行检测和比较。结果 DEXA定量显示 1、5、6区术后BMD增加 ,其中 1区增加显著 (10 42 % ) ,2、3、4、7区减少 ,其中 7区减少显著 (16 5 % )。术后 1年内BMD在 6、7区呈持续显著减低 4 4%～ 5 6 % ,在 3、4、5区呈持续显著增高 6 2 %～ 6 6 % ,而 1、2区仅轻微减少1 3%～ 1 8% ,术后 2～ 3年BMD改变轻微。相比之下 ,手术前、后X线摄片均未能显示任何BMD差异 ,更未能定量显示。结论 DEXA具有辐射量低、敏感性强、重复检查误差小和定量正确性高等优点。手术前、后各区BMD变化对评价THR CL股骨头假体固定质量的意义。

Objective To get the technique for the measurement of bone mineral density(BMD) in defined areas around metal implants.Methods Seven cses of BMD in the regions of proximal femora adjacent to metal cementless femoral implants before and 1-3 years after the cementless total hip replacement(THR-CL) were determined and compared by means of dual-energy x-ray absorptiometry(DEXA) and radiography.Results It was shown that the BMD values increased immediately after operation at zones 1,5,and 6 with the maximum increase at zone 1(10 42%),but reduced immediately after operation at zones 2,3,4 and 7 with the maximum reduction at zone 7 (16 5%).One year after the operation,BMD was continuously decreasing at zones 6 and 7,but significantly increasing at zones 3,4 and 5.In the three years after that,BMD change in defined areas was only slightly seen.But x-ray films did not show any difference between the control and operated femora.Conclusion It is suggested that DEXA has the advantages of low radiation,high sensitivity,reproducible,and high precision.Therefore,it is much better than the clinicoe radiography.This paper also discussed the right procedures for the determination of BMD with DEXA,and the significance of BMD value of each region of interest around femoral components to judge the fixation quality for femoral components.