Carlson Timothy, Beck Aaron, Kohler James, Mosiman Samuel, Nickel Brian
University of Wisconsin Hospital and Clinics, Department of Orthopedics and Rehabilitation, 600 Highland Avenue, Madison, WI, 53792, United States of America.
UW Health, 600 Highland Avenue, Madison, WI, 53792, United States of America.
J Orthop. 2025 Mar 25;70:138-144. doi: 10.1016/j.jor.2025.03.052. eCollection 2025 Dec.
There has been an increase in cementless total knee arthroplasty (TKA) across the country. Although radiographic classification systems of the knee exist, these algorithms have not been correlated to bone mineral density (BMD). We aimed to correlate radiographic measurements of the knee with preoperative BMD and develop a model predictive of osteopenia.
We prospectively enrolled 100 patients, scheduled to undergo elective TKA, to obtain a preoperative dual energy x-ray absorptiometry (DEXA) scan. Four independent surgeons measured cortical indices of the knee on preoperative radiographs and correlated these ratios with local BMD. Intraclass correlations (ICC) were used to assess interobserver reliability and Pearson correlation coefficients (PCC) to describe the strength of relationship between BMD and radiographic ratios. A "Reverse Dorr" model was created to evaluate the ratio of the distal femur cortical indices. Logistic regression was used to predict the odds of having osteopenia.
We found several cortical ratios of the knee correlated with bone mineral density, but the lateral radiograph had the highest correlation. All measurements showed, at a minimum, fair interobserver reliability with most achieving an ICC >0.81. The proximal femur, distal femur ratio, "Reverse Dorr" model, was found to be a strong predictor of osteopenia with an ROC of 0.7335.
This radiographic assessment demonstrates that cortical thickness of the knee is correlated with bone mineral density-most notably on the lateral radiograph. Utilization of the "Reverse Dorr" model was strongly predictive of osteopenia and may help guide implant selection.
在全国范围内，非骨水泥全膝关节置换术（TKA）的应用有所增加。虽然存在膝关节的影像学分类系统，但这些算法尚未与骨矿物质密度（BMD）相关联。我们旨在将膝关节的影像学测量与术前BMD相关联，并建立一个预测骨质减少的模型。
我们前瞻性地纳入了100例计划接受择期TKA的患者，以进行术前双能X线吸收测定（DEXA）扫描。四位独立的外科医生在术前X线片上测量膝关节的皮质指数，并将这些比率与局部BMD相关联。组内相关系数（ICC）用于评估观察者间的可靠性，Pearson相关系数（PCC）用于描述BMD与影像学比率之间关系的强度。创建了一个“反向多尔”模型来评估股骨远端皮质指数的比率。使用逻辑回归来预测骨质减少的几率。
我们发现膝关节的几个皮质比率与骨矿物质密度相关，但外侧X线片的相关性最高。所有测量结果至少显示出观察者间的中等可靠性，大多数测量的ICC>0.81。发现股骨近端与远端的比率，即“反向多尔”模型，是骨质减少的有力预测指标，ROC为0.7335。
这种影像学评估表明，膝关节的皮质厚度与骨矿物质密度相关，最显著的是在外侧X线片上。“反向多尔”模型的应用对骨质减少具有很强的预测性，可能有助于指导植入物的选择。
