Ashkenazi Itay, Morgan Samuel, Shaked Or, Snir Nimrod, Gold Aviram, Khoury Amal, Shemesh Shai, Warschawski Yaniv
Division of Orthopedics, Tel Aviv Sourasky Medical Center, Tel-Aviv, Affiliated to the Sackler Faculty of Medicine, Tel Aviv University, 6423906 Tel Aviv, Israel.
Sackler Faculty of Medicine, Tel Aviv University, 6997801 Tel Aviv, Israel.
SICOT J. 2023;9:13. doi: 10.1051/sicotj/2023009. Epub 2023 May 15.
Pre-operative templating prior to hip arthroplasty has traditionally used implant-company-provided acetates, which assumed a magnification factor between 115% and 120%. In recent years, pre-operative planning has been performed with digital calibration devices, in order to calculate the magnification factor. However, these devices are not without their limitations and are not readily available at many institutions. As previous reports suggest a wide range of magnification factors, the determination of an optimal magnification factor is currently unclear. We investigated the relationship between obesity and gender on the magnification factor in order to improve the accuracy of pre-operative templating.
Ninety-seven consecutive pre-operative calibrated pelvic radiographs using the KingMark calibration were analyzed using the TraumaCad templating software. The magnification factor calculated by the software was considered the true magnification factor and analysis was made in order to assess the effect of sex and body mass index (BMI) on the magnification factor. A linear regression analysis was utilized to create a predictive model for optimal magnification factor value.
Magnification factor was significantly affected by sex (male, 120.0% vs. female 121.2%, p < 0.01) and by categorized BMI (obese 121.8% vs. non-obese 119.9%, p < 0.001). A positive linear association was found between BMI and the magnification factor (r = 0.544). The magnification factor was significantly different between the following sub-groups: obese female, non-obese female, obese male, and non-obese male (p < 0.001). When applying the model formulated by the linear regression analysis, the calculated magnification factor was within 2% of the true magnification factor for the majority of patients (n = 83, 85.6%).
BMI and gender have a significant effect on the magnification factor. Future determination of the magnification factor should consider the influence of these variables in order to improve the accuracy of pre-operative templating in THA.
传统上，髋关节置换术前的模板制作使用植入物公司提供的醋酸盐模板，其假定放大倍数在115%至120%之间。近年来，术前规划通过数字校准设备进行，以计算放大倍数。然而，这些设备并非没有局限性，而且在许多机构中并不容易获得。由于先前的报告显示放大倍数范围广泛，目前尚不清楚最佳放大倍数的确定方法。我们研究了肥胖和性别与放大倍数之间的关系，以提高术前模板制作的准确性。
使用TraumaCad模板软件分析了97例连续的术前经KingMark校准的骨盆X线片。软件计算出的放大倍数被视为真实放大倍数，并进行分析以评估性别和体重指数（BMI）对放大倍数的影响。利用线性回归分析创建了最佳放大倍数值的预测模型。
放大倍数受性别（男性为120.0%，女性为121.2%，p<0.01）和分类BMI（肥胖者为121.8%，非肥胖者为119.9%，p<0.001）的显著影响。BMI与放大倍数之间存在正线性关联（r=0.544）。以下亚组之间的放大倍数存在显著差异：肥胖女性、非肥胖女性、肥胖男性和非肥胖男性（p<0.001）。当应用线性回归分析制定的模型时，对于大多数患者（n=83，85.6%），计算出的放大倍数在真实放大倍数的2%以内。
BMI和性别对放大倍数有显著影响。未来确定放大倍数时应考虑这些变量的影响，以提高全髋关节置换术术前模板制作的准确性。
