Department of Orthopedic Surgery, Deventer Hospital, Nico Bolkesteinlaan 75, 7416 SE Deventer, The Netherlands.
BMC Musculoskelet Disord. 2010 Apr 20;11:74. doi: 10.1186/1471-2474-11-74.
The bone mineral density (BMD) of the distal femur decreases by 16-36% within one year after total knee arthroplasty (TKA) because of the femoral component's stress-shielding effect. The aim of this prospective study was to determine the quantitative change from the baseline BMD in the distal femur 1 year after patellofemoral arthroplasty using dual-energy X-ray absorptiometry (DXA).
Between December 2007 and December 2008, 14 patients had patellofemoral arthroplasty for isolated patellofemoral osteoarthritis. Distal femoral BMD was assessed using DXA in 2 regions of interest (ROI) on the lateral view 2 weeks before and 12 months after patellofemoral arthroplasty. The contra-lateral knee was used as a control, with BMD measurements performed in identical ROIs.
The mean change from baseline BMD in the operated knees after 1 year was -0.169 g/cm2 (95% CI: -0.293 to -0.046 g/cm2) behind the anterior flange (-15%), and -0.076 g/cm2 (95% CI: -0.177 to 0.024 g/cm2) in the supracondylar area 1 cm above the prosthesis (-8%) (p = 0.01 and p = 0.13, respectively). The mean change from baseline BMD in the non-operated knees after 1 year was 0.016 g/cm2 (95% CI: -0.152 to 0.185 g/cm2) behind the anterior flange (2%), and 0.023 g/cm2 (95% CI: -0.135 to 0.180 g/cm2) in the supracondylar area 1 cm above the prosthesis (2%) (p = 0.83, and p = 0.76, respectively).
Our findings suggest that patellofemoral arthroplasty results in a statistically significant decrease in BMD behind the anterior flange.
全膝关节置换术（TKA）后 1 年内，由于股骨部件的应力屏蔽效应，远端股骨的骨密度（BMD）降低 16-36%。本前瞻性研究的目的是使用双能 X 射线吸收法（DXA）确定髌股关节炎置换术后 1 年时远端股骨基线 BMD 的定量变化。
2007 年 12 月至 2008 年 12 月，14 例患者因孤立性髌股关节炎行髌股关节炎置换术。在髌股关节炎置换术前 2 周和术后 12 个月，使用 DXA 在外侧视图的 2 个感兴趣区域（ROI）评估远端股骨 BMD。对侧膝关节作为对照，在相同的 ROI 中进行 BMD 测量。
术后 1 年，患侧膝关节的 BMD 从基线值的平均变化为前突下 0.169 g/cm2（95%CI：-0.293 至 -0.046 g/cm2）（-15%），假体上方 1cm 处髁上区域为 0.076 g/cm2（95%CI：-0.177 至 0.024 g/cm2）（-8%）（p = 0.01 和 p = 0.13）。术后 1 年，非手术侧膝关节的 BMD 从基线值的平均变化为前突下 0.016 g/cm2（95%CI：-0.152 至 0.185 g/cm2）（2%），假体上方 1cm 处髁上区域为 0.023 g/cm2（95%CI：-0.135 至 0.180 g/cm2）（2%）（p = 0.83 和 p = 0.76）。
我们的研究结果表明，髌股关节炎置换术会导致前突下的 BMD 出现统计学上的显著下降。
