How useful is templating for total knee replacement component sizing?

Area of Science:

• Orthopaedic surgery
• Medical imaging analysis
• Surgical planning technology

Background:

• Accurate component sizing is crucial for successful total knee arthroplasty (TKA).
• Previous studies have assessed templating accuracy, but few have correlated preoperative digital templating with postoperative radiographic outcomes.
• Evaluating the discrepancy between templated and implanted sizes is essential for refining surgical techniques.

Purpose of the Study:

• To evaluate the accuracy of digital templating in TKA at our institution.
• To compare templated component sizes with actual implanted sizes.
• To determine the impact of preoperative digital templating on radiographic outcomes and identify preferable templated sizes in cases of mismatch.

Main Methods:

• Analysis of 90 sequential PFC Sigma total knee replacements.
• Digital templating applied to 45 cases using a calibrating ball and Agfa Orthopaedic Tools software.
• Independent grading of postoperative radiographs for correct component sizing.

Main Results:

• All digital templates were within one size of the implanted prosthesis.
• Femoral components were more frequently oversized in the non-templated group.
• Tibial trays found to be too small were often templated larger, and those templated too large were often templated smaller, indicating a trend towards improved accuracy with templating.

Conclusions:

• Digital templating, when used with a calibrating device, is a valuable tool in preoperative planning for total knee arthroplasty.
• Templating demonstrates a positive impact on achieving accurate component sizing, potentially reducing errors like oversizing.
• Further refinement of digital templating may lead to even greater precision in TKA component selection.