Computer-assisted patellar resection system: Development and insights

Incorrect resection of the patella during total knee arthroplasty (TKA) can lead to anterior knee pain (AKP), patellar maltracking, patellofemoral impingement, patellar fracture, component loosening, and reduced range of motion. Computer-assisted surgery (CAS) systems for the tibia and femur improve cut accuracy, but no CAS system is available for patellar resection. We developed a system that included an optoelectronic localizer, marker arrays on the patella and instruments, and navigation software. Three users performed resections on artificial patellae mounted in a simulated surgical setup using five techniques (two CAS, three conventional), each repeated at least three times in randomized order. Computer-assisted patellar resection produced better or equal cut symmetry compared to conventional techniques, particularly superoinferiorly. Using CAS with a sawguide produced better results than using CAS freehand with an oscillating saw. This study showed the feasibility of computer-assisted patellar resection, which could lead to reduced pain and complications after TKA. The feedback provided could also make patellar CAS a valuable training tool. (C) 2011 Orthopaedic Research Society. (C) 2011 Orthopaedic Research Society Published by Wiley Periodicals, Inc. J Orthop Res 30:535540, 2012