Patient-specific instrumentation in total knee arthroplasty

Abstract

Background: Patient-specific instrumentation (PSI) is a promising new technology in orthopedic surgery that aims for higher accuracy and simplification of the implantation technique of total knee arthroplasty (TKA) compared to conventional instrumentation. The aim of this article is to describe the advantages and limitations of PSI for primary TKA. Material and methods: A comprehensive literature review was performed on the topic of PSI in knee arthroplasty with respect to evidence for planning, precision, clinical outcomes, intraoperative parameters, cost and efficiency. Results: The three-dimensional computed tomography (3D-CT) has a higher accuracy than 2D-radiography in the preoperative planning of TKA. Most studies postulated no significant effects in favor of the accuracy of PSI versus standard TKA; however, they also did not report that the accuracy was worse with PSI. Regarding clinical outcomes, there is sufficient consensus among the published studies to state that there is no difference in the short and medium term between patients who were operated on using PSI or the conventional technique. A large meta-analysis could find neither a shorter surgery time nor a lower complication rate for PSI TKA. Only intraoperative blood loss proved to be lower compared to the standard technique but with unaffected transfusion rates. Cost-effectiveness analyses suggest that PSI is currently not (yet) cost-effective. Conclusion: Although the currently available study results do not clearly favor PSI technology over the standard technique with respect to various measurable criteria, PSI shows many theoretical and practical advantages.