Schapira Benjamin, Madanipour Suroosh, Iranpour Farhad, Subramanian Padmanabhan
Trauma and Orthopaedics, Royal Free London NHS Foundation Trust, London, GBR.
Trauma and Orthopaedics, Princess Alexandra Hospital, Harlow, GBR.
Cureus. 2023 Feb 12;15(2):e34883. doi: 10.7759/cureus.34883. eCollection 2023 Feb.
Background Templating for total hip arthroplasty has been adopted over recent decades as a reliable and accurate method for pre-operative planning. The use of calibration markers for this process provides a recognised benefit at the expense of cost, availability and error. Many surgeons use a set magnification of 118% to account for calibration errors when templating total hip arthroplasty. This study aims to assess the accuracy of templating with standardised magnifications and assess the effect of BMI on templating accuracy. Materials and methods A retrospective analysis was performed using a single-surgeon series of 119 consecutive total hip arthroplasties. Anteroposterior radiographs were taken pre- or post-operatively without calibration hardware. Pre-operatively, the total hip arthroplasty was templated on TraumaCad (BrainLab Inc, Westchester, IL) using either 118% or 119% calibration magnification. Post-operative magnification was calibrated using the known femoral head diameter. Templated and implanted prostheses were compared for size. Results At 118%, 61.1% of cups matched those templated with 96.3% of cups within two sizes. At 119%, 52.5% of cups used matched their templates with 100% within two sizes. There was no significant difference between 118% and 119% cup size prediction (p=0.49). A trend was noticed in increasing magnification error with increasing BMI. However, BMI had no significant effect on the accuracy of templating cup size within two cup sizes (p=0.58). . Templating acetabular cups using a set magnification of 118% or 119% yields accurate results and provides a reliable method to template without calibration equipment. Whilst BMI can affect magnification error, this has no significant effect on the accuracy of implanted cups and stems within two sizes.
近几十年来，全髋关节置换术的模板技术已被用作术前规划的一种可靠且准确的方法。在此过程中使用校准标记虽有公认的益处，但存在成本、可用性和误差方面的问题。许多外科医生在进行全髋关节置换术模板操作时使用118%的固定放大倍数来考虑校准误差。本研究旨在评估使用标准化放大倍数进行模板操作的准确性，并评估体重指数（BMI）对模板准确性的影响。
对一位外科医生连续进行的119例全髋关节置换术病例进行回顾性分析。术前或术后拍摄前后位X线片，不使用校准硬件。术前，在TraumaCad（BrainLab公司，伊利诺伊州韦斯特切斯特）上使用118%或119%的校准放大倍数对全髋关节置换术进行模板操作。术后放大倍数通过已知的股骨头直径进行校准。比较模板化和植入假体的尺寸。
在118%的放大倍数下，61.1%的髋臼杯与模板匹配，96.3%的髋臼杯在两个尺寸范围内匹配。在119%的放大倍数下，52.5%使用的髋臼杯与模板匹配，100%在两个尺寸范围内匹配。118%和119%髋臼杯尺寸预测之间无显著差异（p = 0.49）。随着BMI增加，放大误差有增加趋势。然而，BMI对两个髋臼杯尺寸范围内模板化髋臼杯尺寸的准确性无显著影响（p = 0.58）。使用118%或119%的固定放大倍数模板化髋臼杯可产生准确结果，并提供一种无需校准设备的可靠模板方法。虽然BMI会影响放大误差，但这对两个尺寸范围内植入的髋臼杯和股骨柄的准确性无显著影响。
