📍 Manassas, Fair Oaks, & Gainesville, VA 📞 703-393-1667
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Dr. Zachary Weidner, M.D.
HIP & KNEE REPLACEMENT SURGEON
MAKO Robotic Partial Knee Replacment
There are three compartments to the knee joint: the medial, lateral, and patellofemoral compartments. Partial knee replacement is unique in that only one compartment is replaced at the time of surgery. This explains why partial knee replacement is also referred to as unicompartmental knee replacement. Total knee replacement is different in that the entire knee is replaced with implants. All the ligaments of the knee are maintained in a partial knee replacement whereas in a total knee replacement the anterior cruciate (ACL) and often the posterior cruciate ligaments (PCL) are excised. Maintaining the cruciate ligments helps the knee to feel more normal because of the proprioception capabilities inherent to these ligaments.
Partial knee replacement can be performed either with or without robotic assistance. When the robot is used it is called a MAKOplasty ®. MAKOplasty ® is unique in that a CT scan is performed preoperatively so that the surgical plan for the robot can be prepared using much more information than is obtained from standard knee x-rays. The robot then guides the surgeon intraoperatively using visual, tactile, and auditory feedback so that only the bone required to be removed to fit the implants is removed. It allows for precision down to millimeters and essentially removes any error that can occur during the normal surgical steps of cutting the bone, balancing the joint, and appropriately aligning the implants.
The benefits of partial knee replacement compared to total knee replacement include that it is a smaller surgery with a quicker recovery, it allows for a more normal feeling knee, and there is a greater chance of returning to high level activities such as running. The main downside of partial knee replacement is that the associated revision rate, or need for a secondary surgery on the knee, is higher compared to total knee replacement. This is because there is a higher rate of implant loosening over time with partial knee replacements. Also, because only one part of the knee is replaced, a patient can develop arthritis in the other compartments of the knee which can lead to pain and the need for surgery to convert to a total knee replacement to get rid of all the arthritis.
FAQs — Partial Knee Replacement (MAKOplasty)
Q: What is partial knee replacement?
A: Partial knee replacement (also called unicompartmental knee arthroplasty or MAKOplasty when performed with the MAKO system) replaces only the damaged portion of the knee rather than the entire joint. It is an option for patients whose arthritis is limited to one compartment of the knee.
Q: Am I a candidate for partial vs. total knee replacement?
A: Partial knee replacement requires that arthritis be limited to one compartment (typically the medial or inner side) and that the knee ligaments are intact. Patients with arthritis throughout the knee or certain other conditions may be better served by total knee replacement. Dr. Weidner will evaluate your X-rays and exam findings to recommend the best option.
Q: What are the advantages of partial knee replacement?
A: Partial knee replacement preserves more of the natural knee, including the cruciate ligaments, often resulting in a more natural-feeling knee after recovery. It involves a smaller incision, less blood loss, shorter surgery time, faster recovery, and less post-operative pain than total knee replacement in most cases.
Q: Can a partial knee replacement be converted to total if needed later?
A: Yes. If arthritis progresses to other compartments over time, a partial knee replacement can be revised (converted) to a total knee replacement. This is a routine procedure for experienced joint replacement surgeons like Dr. Weidner.
Q: How does the MAKO system improve partial knee replacement?
A: The MAKO robotic system creates a CT-based 3D model of your knee before surgery, allowing Dr. Weidner to pre-plan implant placement precisely. During surgery, the robotic arm provides haptic feedback that prevents the surgeon from cutting outside the planned boundaries — resulting in more accurate and consistent implant positioning than traditional techniques.