Intra-operatively Measurements with a Computer Navigation Software System Before and After Posterior Cruciate Release in Patients Undergoing Primary Total Knee Arthroplasty

The goal of this study is not to change the patients' outcome. It is just to perform a measurement during the surgical procedure that implies adding a step to the procedure. When performing a total knee arthroplasty (TKA) the surgeon decides if he wants to preserve the posterior cruciate ligament (PCL) or if he wants to resect it. Both procedures can be done and papers with evidence supporting both procedures have been published over the last decades. Nevertheless, few studies have quantified the changes in the gap (between femur and tibia) balancing when the posterior cruciate ligament is resected. Participants in this study will be submitted to a total knee arthroplasty assisted by a navigation software system and robot. We will not submit patients to a new treatment or implants. These are patients that would be submitted to this type of total knee arthroplasty regardless they participate in this study or not. The objective is to quantify, with the use of this software, how much does the gap balance changes when we perform a primary total knee replacement sacrificing the posterior cruciate ligament, just by adding a step to the normal procedure. To do that, we will analyse data captured intra-operatively by optical motion capture technology from Smith & Nephew NAVIO™ Surgical System (robot and computer navigation software) during the surgical steps: -After medial and lateral meniscus anterior horns resection, osteophyte resection and other soft-tissue release except for PCL resection: as we always do in a standard procedure -After bone cuts but before PCL resection, measuring with trial implants in place: extra measurement specific to this study -After bone cuts and PCL resection, measuring with trial implants in place: as we always do in a standard procedure. Normal surgical time of approximately 70 minutes may be extended by 3 to 5 minutes while additional data is captured. This way, only one extra measurement that doesn’t involve a major alteration of the procedure is done, and there is a very low risk/negligible risk for the patient and surgical outcome. The goal of this study is not to change the patients' outcome. The surgeon who is chief investigator of this study will be the only one performing surgery. He is a fellowship arthroplasty trained orthopaedic surgeon (since 2004) with years of experience on total knee replacements (over 120 procedures a year) and robotic surgery (more than 60 procedures a year). All the data collected in the operating theatre during a single surgery will be store in a digital database password protected. Only researchers involved will have access to it and they are aware of privacy laws and have signed a confidentiality form. No information is collected and stored without prior informed and signed consent from patients and patients are aware that this data may be subject of analysis for future and ongoing studies that may be conducted and published. Under no circumstance will we use patients’ identifiable information on published studies, and patients are free to refuse to allow their data storage in the database without prejudice to their healthcare.