Partial Knee Replacement Frequently Asked Questions:

Q. What is Partial Knee Replacement, and How is it Different from Total Knee Replacement?

A. In total knee replacement surgery, the damaged surfaces of all three bones are resurfaced with metal and plastic implants. Using special, precision instruments, our surgeon will typically remove the damaged surfaces. The replacement surfaces will then be fixed into place. The surface of the upper bone is replaced with a rounded metal component that comes very close to matching the curve of your natural bone. The surface of the lower bone is replaced with a flat metal component and a slab of ultra-high-molecular weight polyethylene plastic to serve as the cartilage, or the entire component may be plastic. The undersurface of the kneecap also may be replaced with a round disc made of the same polyethylene plastic. Partial knee replacement is an option for patients who do not require total knee replacement because some of the joint surfaces are still healthy. In partial knee replacement surgery, the surgeon removes only the diseased portion of the knee before placing the implant, leaving the healthy portion untouched. This means that the surfaces are replaced on only one side of the joint, that is, only one of the rounded projections is replaced beneath it.

Q. What is the difference between this minimally invasive procedure (MIS) and the standard procedure?

A. The MIS procedure involves removing only the diseased portion of the knee, through an incision that is one-third to one-fourth the size of a traditional knee replacement incision. Rehabilitation time after the MIS procedure is estimated at five weeks. Traditional, total knee replacement surgery involves removing or resurfacing more parts of the knee, including both condyles and often the underside of the kneecap. Rehabilitation time for a total knee is estimated at 12 weeks. Most total knee replacements are performed on patients 65 years of age and older; whereas, the majority of patients receiving the MIS procedure for the Uni Knee are 55 and older. If partial knee replacement is not an option for you, you may want to inquire about minimally invasive procedures for total knee replacement.

Q. What are the benefits of the MIS procedure compared to traditional knee replacement surgery?

A. Clinical results suggest that patients who undergo the MIS procedure are able to have the procedure performed in an outpatient setting with just an overnight stay, faster rehabilitation and a smaller incision scar. Patients may also experience an increased range of motion after recovery. A successful Uni Knee replacement may delay, and in some cases, prevent a more extensive knee replacement surgery.

Q. Is MIS Partial Knee Replacement Better?

A. The MIS partial knee replacement procedure may not help your new knee joint function better or last longer than traditional surgery, but it might help make your surgery, recovery, and rehabilitation faster and easier for you.

Q. How do I know if I am a candidate for the MIS procedure and Partial Knee Replacement?

A. A number of factors can determine whether a patient is qualified to undergo the MIS procedure for the Uni Knee replacement and how successful the procedure will be. An ideal candidate is someone who has osteoarthritis of the knee that is isolated to only one condyle (or compartment) of the knee. Candidates also may include people who are not responding to other forms of treatment such as medication, arthroscopy or cartilage transfers. The Uni Knee replacement is not performed on individuals with rheumatoid arthritis.

Q. How Do I Decide?

A. The decision to have the MIS procedure for a Uni Knee replacement is up to you and your orthopaedic surgeon. Your doctor will consider a number of factors, including: medical history, weight, health status, and anatomical structure, including bone structure and extent and pattern of arthritis.