Balancing Kinematically Aligned Total Knee Replacements During Total Primary Knee Arthroplasty Using Verasense

Total Knee Replacement (TKR) is an operation to help with the pain and decreased function that happens with end stage arthritis of the knee. This operation has been shown to be very successful at relieving pain and improving patient mobility; however, some studies have shown that up to 20% of TKR recipients are not happy with their knee replacement. All of the reasons why some patients are not pleased with the outcome of surgery are not known, but one of the possible causes is the way the implants are placed, or aligned, during surgery. Most TKRs are aligned in a fashion that the bones in the leg are completely straight after surgery. This is known as mechanically aligning a TKR. A different alignment method known as kinematic alignment respects the natural bow legged or knock kneed alignment of the patient. It is hoped that kinematically aligning a knee replacement will improve how the knee feels to the patient and therefore improve their satisfaction. Another potential factor affecting the outcomes of TKR is obtaining optimal soft tissue balance. The challenge with balancing a TKR is that traditional operative techniques rely on subjective feel of the knee stability during surgery. The balance or tension in the knee can however be objectively measured using specialized intraoperative pressure sensing devices. The purpose of this study is to assess the impact of kinematically aligned TKR on the pressures measured by Verasense during total knee replacements. The study will also determine if differences in the pressure measured during TKR surgery impact patient outcomes after surgery.