THE SURGEON PLAYS AN IMPORTANT ROLE IN SIZE PLANNING WITH PATIENT-SPECIFIC INSTRUMENTATION FOR TOTAL KNEE ARTHROPLASTY

Patient specific instrumentation (PSI) for total knee arthroplasty (TKA) may improve component position and sizing. However, little has been reported about the accuracy of the default plan created by the manufacturer. The purpose of the study was to evaluate the reliability of the manufacturer plan and the impact of surgeon's changes on the final accuracy of the cutting guide sizes. The planned sizes of 45 TKAs were prospectively recorded from the in the initial manufacturer's proposal and from the final plan modified after surgeon's evaluation and compared to the actually implanted sizes. The manufacturer's initial proposal differed from the final implant in 20% of the femoral and 51.11% of the tibial components, while the surgeon's plan in 13.33% of the femoral and 26.67% of the tibial components. Surgeon's modifications in the pre-operative were carried out for 11.11% of the femoral components and 51.11% of the tibial ones (p = 0.0299). Appropriate modification occurred in of 88% and 76% of femoral and...