Gislason Magnus Kjartan, Lupidio Francesca, Jónsson Halldór, Cristofolini Luca, Esposito Luca, Bifulco Paolo, Fraldi Massimiliano, Gargiulo Paolo
Institute for Biomedical and Neural Engineering, Reykjavik University, Iceland.
Institute for Biomedical and Neural Engineering, Reykjavik University, Iceland; University of Bologna, Department of Industrial Engineering, Italy.
Clin Biomech (Bristol). 2020 Aug;78:105092. doi: 10.1016/j.clinbiomech.2020.105092. Epub 2020 Jun 11.
The aim of the study was to compare the bone mineral density changes between unmatched patients undergoing total hip arthroplasty receiving uncemented and cemented type of implants. Previous studies have used DEXA or a two dimensional analysis to estimate the bone quality following total joint replacement, whereas this study presents the changes in three dimensions.
Fifty subjects both male and females receiving both cemented and uncemented type of implant were recruited. Two CT scans were taken of each subject, the first at 24 h post surgery and the second one 1 year after surgery. The scans were calibrated using a phantom converting the Hounsfield units to bone mineral density values in g/cm. The two scans were registered together using anatomical landmarks and resliced to compare the two femurs in the identical frame of reference. The bone density gain and loss was calculated by comparing density values between the two sets of scans.
The results showed that most of the bone loss was located around the Lesser Trochanter and some bone density gain at the distal tip of the implant. The three dimensional density changes occur differently between individuals and the study showed no correlation of bone loss with age.
The bone loss occurred mostly at the proximal femur, which is in agreement with previously presented studies. By carrying out three dimensional analysis on the bone gain and loss on the femur, it is possible to identify the patients that are showing high degree of bone loss.
本研究的目的是比较接受非骨水泥型和骨水泥型植入物的全髋关节置换术患者之间的骨密度变化。以往的研究使用双能X线吸收法（DEXA）或二维分析来评估全关节置换术后的骨质量，而本研究呈现的是三维变化。
招募了50名接受骨水泥型和非骨水泥型植入物的男性和女性受试者。对每个受试者进行两次CT扫描，第一次在术后24小时，第二次在术后1年。使用体模对扫描进行校准，将亨氏单位转换为以克/立方厘米为单位的骨密度值。利用解剖标志将两次扫描配准在一起，并重新切片以在相同的参考框架下比较两侧股骨。通过比较两组扫描之间的密度值来计算骨密度的增减。
结果显示，大部分骨丢失位于小转子周围，植入物远端有一些骨密度增加。个体之间的三维密度变化各不相同，且研究表明骨丢失与年龄无关。
骨丢失主要发生在股骨近端，这与之前的研究结果一致。通过对股骨骨量增减进行三维分析，有可能识别出骨丢失程度较高的患者。
