Comparison of polyethylene thickness between patient-specific templating and conventional techniques in total knee arthroplasty

Abstract

Background: Polyethylene thickness in total knee arthroplasty (TKA) can affect outcomes and the need for revision surgery. The thickness of polyethylene is dependent on the level of the proximal tibial cut. Computer-assisted techniques can accurately determine the level of tibial cut and help in bone preservation. Objective: The aim was to compare the thickness of the polyethylene inserts in patients who have undergone TKA using patient-specific templating (PST) versus conventional instrumentation. Patients and Methods: We prospectively collected TKA data from the Egyptian Community Arthroplasty Register (ECAR), with controlled age, sex, BMI, deformities, and preoperative knee society score (KSS). The total number included was 315 knees (150 conventional TKA knees and 165 PST knees). All TKAs were done by one surgeon. Statistical analysis was done using Microsoft Excel and R programming language. Results: The average polyethylene thicknessin the conventional and PST groups were 11.6 (SD=2.9) and 11.1 (SD=2.1) mm, respectively, which was not statistically significant. However, there was a significant difference in outliers in favor of PST (maximum thickness was 14 and 20 mm in the PST and conventional groups, respectively). The PST group had more improvement in the KSS (p=0.023). Conclusion: This study showed that PST reduced the outliers in polyethylene thickness, which helps in the preservation of bone stock and subsequently may improve implant survival. This study may not be representative as the operations were done by one surgeon. Therefore, further studies are required.