Planning on CT-Based 3D Virtual Models Can Accurately Predict the Component Size for Total Knee Arthroplasty

Area of Science:

• Orthopedic Surgery
• Medical Imaging
• Biomedical Engineering

Background:

• Accurate implant sizing in total knee arthroplasty (TKA) is crucial for surgical efficiency and optimizing outcomes.
• Traditional methods may lead to workflow complexities and increased instrument tray requirements.
• Three-dimensional (3D) virtual planning using computed tomography (CT) offers a potential solution for improving preoperative size prediction.

Purpose of the Study:

• To quantify the accuracy of surgeon-validated, CT-based 3D virtual planning for predicting total knee arthroplasty implant component sizes.
• To assess the concordance between preoperatively planned implant sizes and the finally implanted components for femoral and tibial prostheses.

Main Methods:

• Retrospective review of 336 TKA cases (267 patients) utilizing CT-based patient-specific instrumentation.
• Comparison of preoperative default and surgeon-validated 3D virtual plan sizes against the actual implanted component sizes for femur and tibia.
• Statistical analysis, including Kappa statistics, to determine the concordance between planned and implanted sizes.

Main Results:

• Surgeon modifications to manufacturer preplanned sizes were minimal (0.9% femoral, 2.7% tibial).
• Surgeon-validated plan sizes were used in 95.8% of femoral and 92.6% of tibial components.
• Excellent concordance was observed between surgeon-validated plans and implanted sizes (femoral κ=0.951, tibial κ=0.902); the most common change was a one-size increase for the tibial component.

Conclusions:

• CT-based 3D virtual planning is a valuable tool for surgeons to accurately predict TKA implant sizes.
• The evaluated system demonstrates high accuracy in predicting both femoral and tibial component sizes, supporting its clinical utility.
• This planning approach can streamline surgical workflow and potentially reduce the need for extensive instrument sets.