Partial knee replacement is a surgical option that can restore function and independence in eligible patients. It's a more complicated procedure than total knee replacement but generally results in high post-surgical activity levels and high patient satisfaction.
A partial knee replacement removes damaged portions of your knee and replaces them with a prosthesis made of metal, plastic, or ceramic. The most common reason for a knee replacement procedure, whether total or partial, is to treat severe, chronic pain or stiffness, usually from osteoarthritis of the knee.
The difference between partial and full knee replacement is how much of your knee is replaced with a prosthetic. Your knee is made up of three sections called "compartments." The three compartments are:
A total knee replacement removes all three compartments and replaces them with prosthetics. A partial knee replacement only replaces one (unicompartmental) or two (bicompartmental) knee compartments.
The success rate of partial knee replacement is high. Studies show that around 90% of unicompartmental knee arthroplasties—the most common kind of partial knee replacement—still perform well after ten years when performed in patients under 60 years of age.
In cases where partial knee replacement surgery fails, the most common reason is the development of arthritis in the rest of the knee, necessitating a conversion to total knee replacement. Even when the surgery fails for other reasons, partial knee replacement failure symptoms resemble arthritis symptoms: pain, stiffness, instability, and swelling of the knee.
Partial knee replacement offers several advantages for eligible patients, but it isn't without risks.
Many of the benefits of a partial knee replacement are the same as those of a total knee replacement:
Despite the similarities, eligible patients may prefer a partial knee replacement because of its advantages over total knee arthroplasty. When comparing partial knee replacement to total knee replacement:
Though rare, partial knee replacement carries the same risks as any surgery:
Besides the standard surgical risks, partial knee replacement problems include:
The requirements for partial knee replacement are narrow, meaning it isn't an option for everyone. Ideal candidates for partial knee replacement:
Partial knee replacement may not be right for people who:
Before recommending a partial knee replacement, your doctor will conduct a physical exam of your knee and discuss with you your medical history and symptoms. They will likely order medical imaging, such as X-rays or MRIs, to get a better idea of the condition of your knee and confirm what treatment options you're a candidate for, including partial knee replacement.
If surgical treatment is recommended, your doctor will also discuss pre-operative instructions with you, such as whether you’ll need to suspend certain medications before the operation, what kind of anesthetic you'll receive, and when to start fasting before the procedure.
When you have the operation, the surgeon will make incisions in your knee, remove the damaged knee compartment, and install the prosthetic.
The partial knee replacement recovery timeline is shorter than for a total knee replacement. Most people go home the same day and return to many of their everyday activities in about six weeks. You'll work with a physical therapist to regain range of motion and strength following the surgery.
Depending on your job, you may be able to return to work sooner than six weeks. People with desk jobs may return to work in as little as two weeks. You may want to discuss your lifestyle with your surgeon before the operation to plan for assistance in the house and get advice on how long you should take off work. Remote workers may be able to resume working within days of their surgery.
After a partial knee replacement, you'll enjoy a higher quality of life with less knee pain and stiffness. You'll also be able to return to many activities, such as walking, hiking, swimming, and other low-impact sports. However, it's best to avoid repetitive, high-impact sports and activities that put a lot of stress on the knee, such as sports with a lot of twisting motions.
After your operation, you'll be more independent and able to do lots of things that may have been painful before. However, there are certain things you should avoid after a partial knee replacement:
Partial knee replacements typically last 10-15 years or more before they need revision surgery. If your knee arthritis worsens in the years following a partial replacement, your doctor may recommend conversion to a total knee replacement.
In most cases, you'll be able to start walking with assistance (a walker or crutches) the day of your surgery.
Unicompartmental or bicompartmental knee surgery usually takes between one and two hours to complete.
People generally return to most of their everyday activities within six weeks, though you can expect to continue physical therapy for several months after the operation.
People who receive a partial knee replacement report less pain, high activity levels, and high rates of satisfaction with the results.
Studies indicate that the average age for a partial knee replacement is 64, but it's becoming increasingly common in younger people.
Because it involves smaller incisions and damages fewer tissues in the knee, partial knee replacements are generally less painful than total knee replacements.
The most common complication of partial knee replacement is mechanical problems with the implant, and complications are relatively uncommon.
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