Unicompartmental knee replacement is a surgical procedure that involves replacement of only the diseased surface of the joint instead of the entire joint. The knee can be divided into three compartments: patellofemoral, the compartment in the front of the knee between the knee cap and thigh bone, medial compartment, on the inside portion of the knee, and lateral compartment which is the area on the outside portion of the knee joint. The surgeons at Perth Hip and Knee may recommend unicompartmental knee resurfacing if your arthritis is limited to only one compartment of the knee.
Perth Hip and Knee surgeons currently perform unicompartmental knee replacement (UKR) with Robotic assistance. SJOG Subiaco have purchased the Stryker Mako Robotic Surgical System. This system utilises pre-operative CT scans to form three-dimensional model of your knee. During the operation the surgeon collects information about the soft tissue balance of the knee. This information is combined with the CT scan and allows the surgeon to perform a virtual operation on the computer.
Once the optimum position has been ascertained for the femoral (thigh bone) component and the tibial (leg bone) component, the robotic arm is then utilised to mill the bone ends and allow exact placement of the implants. This technology has been utilised in the United States since 2006. It was introduced into Australia by our surgeons in April 2015. The indications for partial knee replacement are not changed by the use of the robot. Accuracy of implantation has been shown to be improved.
Currently all robotic cases in Australia are closely followed up to determine if this technology will decrease the previously high revision rates seen in unicompartmental knee replacement. These have previously had a 20% failure rate at 10 years post-surgery compared to less than 6% with a total knee replacement. It has been shown this is due to either the implant coming loose or progression of disease to the other side of the knee. We are confident that the robotic assistance will help us place the implants more accurately, which should decrease the rate of implants coming loose.
The robot also assists our surgeons to balance the knee throughout the full range of motion preventing overloading of the other parts of the knee. This together with our surgeon’s appropriate selection of patients prevents revision due to progression of disease.
The indications for Robotic assisted UKR are the same as for standard UKR.
Following your robotically assisted knee replacement, you will be taken to the recovery room to be monitored, then shortly after transferred to the ward. Our team use multimodal pain relief to reduce post-operative pain. To help reduce the swelling elevate the leg and apply ice packs on the knee. You will be standing within hours of the procedure, within an expected discharge from hospital within 2 days. You will be instructed about the activities to be avoided and exercises to be performed for faster recovery. A rehabilitation program may be advised for a speedy recovery.
Risks and complications
Are the same as for the standard UKR with no additional risks being identified from the surgery.