Comparison of digital and plain radiography preoperative templating in total knee arthroplasty

The accuracy of digital templating in the preoperative planning of total knee arthroplasties: A systematic review and meta-analysis

AIMS

Accurately predicting the implant size in total knee arthroplasties could increase the efficiency of the operation, decrease the costs associated with the procedure and result in improved patient outcomes. To substantiate its continued use, digital templating must demonstrate itself to be an accurate tool in predicting component size in order for surgeons to confidently use it to optimize the procedure.

METHODS

A systematic literature review was performed and identified 16 studies within the Pubmed, Ebsco and Ovid-Embase databases, with 1189 TKR prostheses included for analysis. A quality of evidence assessment was performed on each study depending on the study design. A random effects meta-analysis model was used to pool overall implant accuracy and the reported inter-rater agreement when performing digital templating and displayed in a forest plot. Meta-regression was used analyze potential factors that may affect the accuracy of digital templating.

RESULTS

The pooled proportion of accurate templates with 0 margin of error was found to be 56% (52-61, 95CI), which increases to 96% (0.94-0.98, 95CI) when allowing for a 1 size margin of error. Subgroup analysis between femoral and tibial components concluded no statistically significant difference.

CONCLUSIONS

This study supports the continued use of digital templating for planning total knee arthroplasties and recommends further subgroup analysis of patient age, body mass index and sex against accuracy. This review was registered in the International Prospective Register of Systematic Reviews Database under ID: CRD420222367461. No funding was provided for the completion of this systematic review.

BACKGROUND

Templating in the preoperative planning of total knee arthroplasties is a vital step in ensuring maximum operative efficiency. A method that can accurately predict the required implant size within 1 size could improve theatre turnover, decrease costs and benefit patient outcomes. The current literature on the accuracy of digital templating in total knee arthroplasties lacks a systematic review calculating the overall accuracy of the process, this study aims to address this gap.

Reliability and accuracy of digital templating for the humeral component of total shoulder arthroplasty

BACKGROUND

This experimental study evaluated the interobserver reliability and accuracy of pre-operative digital templating for humeral head size, stem size and neck angle for total shoulder arthroplasty.

METHODS

Twenty-five patients underwent a total shoulder arthroplasty with a single prosthesis. Four independent, blinded surgeons (two experienced shoulder surgeons and two PGY-6 fellows) used pre-operative radiographs and templating software to generate templates of the humeral head, stem and neck for each patient. Interobserver reliability was calculated using weighted kappa (κ) analysis. Accuracy was assessed by comparing templates to actual implant sizes.

RESULTS

Interobserver reliability was fair to substantial (κ = 0.26 to 0.71) for head size, fair to substantial (κ = 0.39 to 0.72) for stem size and slight to fair (κ = 0.16 to 0.34) for neck angle. Templated head size, stem size and neck angle had accuracies of 53%, 77% and 68% within one size variation, respectively. Experience did not affect accuracy (p = 0.11 to 0.48).

CONCLUSIONS

Digital templating is not a useful guide for pre-operative surgical planning and should not be used to select a prosthesis.

The accuracy and reliability of pre-operative templating in revision total knee arthroplasty. A comparison of analogue and digital methods

AIMS

To determine whether the size of the prostheses used in revision knee arthroplasty may be accurately and reproducibly predicted using analogue or digital pre-operative templating techniques.

METHODS

Pre-operative radiographs were templated using analogue radiographs and acetate templates, digital radiographs and acetate templates and digital radiographs and digital templating software.

RESULTS

Overall accuracy of predicting the size of implant used at surgery was 44%. There was no significant difference in the accuracy of the various templating techniques (p = 0.098).

CONCLUSIONS

Templating in revision knee arthroplasty is neither of suitable accuracy nor reliability enough to safely recommend its use for implant size prediction.

Digital templating in primary total hip and knee arthroplasty

The use of digital radiography is becoming more prevalent in orthopedics. This transition impacts the ability to preoperatively plan for implants in total hip arthroplasty (THA) and total knee arthroplasty (TKA). This article reports on the clinical success of digital templating using the Advanced Case Plan (Stryker Imaging, Flower Mound, Texas) system in primary THA and TKA. Digital radiographs of 269 consecutive patients undergoing primary THA (93 cases) or TKA (176 cases) were templated using the Advanced Case Plan digital software package. A 25.4-mm metallic sphere was used as a calibrating marker. Anteroposterior hip and lateral knee radiographs were digitally templated preoperatively and compared to the actual size of the implants at the time of surgery. The accuracy of calibrating images using the metallic sphere was validated by measuring the diameter of femoral heads on 25 postoperative hip radiographs. Digital templating was accurate in predicting the correct implant size in 58.5% of THAs and 66% of TKAs. In 93% of THAs and 98.5% of TKAs, preoperative templating was within 1 size of the final implant. There were no cases in which the predicted implant size varied from the final components by >2 sizes. Calibrating the image using the metallic sphere marker was found to be highly accurate, predicting the correct femoral head size within 1.5 mm in all 25 cases (7 hemiarthroplasties and 18 THAs). Digital templating is an effective means for predicting the size of THA and TKA components, thus remaining a viable option as we transition into the modern era of digital radiography. Future studies will evaluate interobserver reliability and the impact of level of training on templating accuracy.