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Ortho Blogs

Partial Knee Replacements

by Dr. Todd Curran

Ortho Blogs

Partial Knee Replacements

by Dr. Todd Curran

Over the last several years, there has been an increased interest in partial knee replacements. With improved surgical techniques and materials, shorter hospital stays, and better outcomes, partial knee replacements are becoming more prevalent in the appropriate patient population.

One type of partial knee replacement is patellofemoral arthroplasty (PFA), or “knee cap replacement.” The PFA procedure replaces the undersurface of the knee cap (patella) with a plastic button and the groove on the end of the thigh bone (femur) with a metal component. The ideal candidate for PFA should be fairly asymptomatic with walking on flat ground but experience an increase in pain when going up and downstairs, sitting for prolonged periods of time and transitioning from a sitting to a standing position.

Why You May Need a Partial Knee Replacement

Arthritis isolated to the patellofemoral joint may occur in up to 9 percent of people older than 40 years and is more common in women, who often have subtle patellofemoral maltracking or malalignment. Studies have shown that 24 percent of women with symptomatic knee arthritis have localized patellofemoral arthritis. Total knee arthroplasty (TKA) for isolated patellofemoral arthritis results in greater than 90 percent “excellent” results, but may not be desirable for young, active patients. PFA has achieved excellent pain relief in about 90 percent of patients at 10 years and allows for quicker recovery.

Knowing if You Qualify for a Partial Knee Replacement

Candidates for PFA have pain that is mainly located at the front of their knee; have a documented history of severe cartilage damage isolated to the patellofemoral joint; and have failed extensive nonsurgical treatments like anti-inflammatory medications, physical therapy, bracing, injection therapy and activity modification. The surgical procedure takes about an hour to complete and typically requires a one- to two-day stay in the hospital. The goal of the hospital stay is achieving independence with rehabilitation and adequate pain control with oral medications. After discharge from the hospital, a physical therapy program will be started to help with full recovery. A walking aid may be needed for up to a month, and return to work depends on the physical demands of the job. Most patients can return to office work in two weeks. The vast majority of patients will be able to return to most sports and activities.

Despite excellent success with PFA in the correct patient, there is a possibility that some patients will have progression of arthritis in other parts of the knee, requiring conversion to a TKA. Fortunately, conversion of a PFA to TKA is relatively straightforward and successful. Recent studies have shown that PFAs have the same complication and revision rate as TKAs.

PFA offers a viable alternative for isolated patellofemoral arthritis in a young, active patient who has failed conservative measures.

The First Step.

From diagnosis and treatment to recovery and rehabilitation, OSS Health was founded on the beliefs that we can build a better healthcare experience. The goal of our highly trained physicians and staff is to get our patients back to an active, healthy lifestyle. 


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