Petretta Robert, Strelzow Jason, Ohly Nicholas E, Misur Peter, Masri Bassam A
Department of Orthopaedics, University of British Columbia, 3114-910 W10th Avenue, Vancouver, BC, V5Z 1M9, Canada.
Clin Orthop Relat Res. 2015 Dec;473(12):3752-9. doi: 10.1007/s11999-015-4321-y.
Templating is an important aspect of preoperative planning for total hip arthroplasty and can help determine the size and positioning of the prosthesis. Historically, templating has been performed using acetate templates over printed radiographs. As a result of the increasing use of digital imaging, surgeons now either obtain additional printed radiographs solely for templating purposes or use specialized digital templating software, both of which carry additional cost.
QUESTIONS/PURPOSES: The purposes of this study was to compare acetate templating of digitally calibrated images on an LCD monitor to digital templating in terms of (1) accuracy; (2) reproducibility; and (3) time efficiency.
Acetate onlay templating was performed directly over digital radiographs on an LCD monitor and was compared with digital templating. Five separate observers participated in this study templating on 52 total hip arthroplasties. For the acetate templating, the digital images were magnified to the scaled reference on the templates provided by the manufacturer (ratio 1.2:1) before templating using a 25-mm marker as a reference. Both the acetate and digital templating results were then compared with the actual implanted components to determine accuracy. Interobserver and intraobserver variability was determined by an intraclass correlation coefficient. Observers recorded time to complete templating from the time of complete upload of patients' imaging onto the system to completion of templating.
Both acetate and digital templates demonstrated moderate accuracy in predicting within one size of the eventual implanted acetabular cup (77% [199 of 260]; 70% [181 of 260], respectively; p = 0.050; 95% confidence interval [CI], 0.058-0.32), whereas acetate templating was better at predicting the femoral stem compared to digital templating (75% [195 of 260]; 60% [155 of 260], respectively; p < 0.001; 95% CI, 0.084-0.32). Acetate templating showed moderate to substantial interobserver agreement (cup intraclass correlation coefficient [ICC] = 0.55; 95% CI, 0.14-0.86; femoral ICC = 0.75; 95% CI, 0.39-0.95) and both methods showed almost perfect intraobserver agreement in reproducibility (acetate cup ICC = 0.82; 95% CI, 0.66-0.97; acetate femoral ICC = 0.86; 95% CI, 0.74-0.97; digital cup ICC = 0.82; 95% CI, 0.68-0.97; digital femoral ICC = 0.88; 95% CI, 0.77-1.0). Acetate templating could be performed more quickly (acetate mean 119 seconds; range, 37-220 seconds versus 154 seconds; range, 73-343 seconds; p < 0.001).
Acetate onlay templating on digitally calibrated images can be a reliable substitute for digital templating using specialized software. It is quicker to perform and much less expensive. Hospitals and practices need not purchase expensive software, particularly at lower volume centers.
Level III, diagnostic study.
模板测量是全髋关节置换术前规划的一个重要方面，有助于确定假体的尺寸和位置。历史上，模板测量是在打印的X线片上使用醋酸盐模板进行的。由于数字成像的使用日益增加，外科医生现在要么仅为模板测量目的获取额外的打印X线片，要么使用专门的数字模板测量软件，而这两种方法都会产生额外费用。
问题/目的：本研究的目的是比较在液晶显示器上对数字校准图像进行醋酸盐模板测量与数字模板测量在以下方面的差异：（1）准确性；（2）可重复性；（3）时间效率。
在液晶显示器上直接在数字X线片上进行醋酸盐覆盖模板测量，并与数字模板测量进行比较。五名独立的观察者参与了这项研究，对52例全髋关节置换术进行模板测量。对于醋酸盐模板测量，在使用25毫米标记作为参考进行模板测量之前，将数字图像放大至制造商提供的模板上的缩放参考比例（1.2:1）。然后将醋酸盐和数字模板测量结果与实际植入的部件进行比较，以确定准确性。观察者间和观察者内的变异性通过组内相关系数来确定。观察者记录从患者影像完全上传到系统到完成模板测量的时间。
醋酸盐和数字模板在预测最终植入髋臼杯的尺寸在一个范围内时均显示出中等准确性（分别为77%[260例中的199例]；70%[260例中的181例]；p = 0.050；95%置信区间[CI]，0.058 - 0.32），而与数字模板测量相比，醋酸盐模板测量在预测股骨柄方面表现更好（分别为75%[260例中的195例]；60%[260例中的155例]；p < 0.001；95% CI，0.084 - 0.32）。醋酸盐模板测量显示出中等至高度的观察者间一致性（髋臼杯组内相关系数[ICC] = 0.55；95% CI，0.14 - 0.86；股骨ICC = 0.75；95% CI，0.39 - 0.95），并且两种方法在可重复性方面均显示出几乎完美的观察者内一致性（醋酸盐髋臼杯ICC = 0.82；95% CI，0.66 - 0.97；醋酸盐股骨ICC = 0.86；95% CI，0.74 - 0.97；数字髋臼杯ICC = 0.82；95% CI，0.68 - 0.97；数字股骨ICC = 0.88；95% CI，0.77 - 1.0）。醋酸盐模板测量可以更快地完成（醋酸盐平均119秒；范围，37 - 220秒，而数字模板测量为平均154秒；范围，73 - 343秒；p < 0.001）。
在数字校准图像上进行醋酸盐覆盖模板测量可以成为使用专门软件进行数字模板测量的可靠替代方法。它执行起来更快且成本低得多。医院和医疗机构无需购买昂贵的软件，尤其是在手术量较低的中心。
III级，诊断性研究。
