Partial knee replacement

Partial knee replacement, or unicompartmental knee arthroplasty, is an option for some patients with arthritis that is confined to a single compartment of the knee. Instead of removing all cartilage from the knee joint and inserting a metal and plastic implant, surgeons remove only the most damaged tissue and resurface the affected area, saving the remainder of an otherwise healthy knee. Patients are typically younger and have tried all other non-surgical treatments, including medications, injections, strengthening exercises, rehabilitation and weight loss.

Partial knee replacement allows surgeons to take the bad and leave the good, removing far less bone and preserving more natural motion. The procedure can also buy time for younger patients with localized knee pain, who may ultimately need a total knee replacement later.

Multiple studies have shown that unicompartmental knee arthroplasty performs well in the vast majority of patients who are appropriate candidates. Because it is minimally invasive surgery, it is less traumatic than total knee replacement. Advantages include a smaller incision, less pain and bleeding, shorter hospitalization, and faster rehabilitation and recovery. In addition, many patients report that a partial knee replacement feels more natural than a total knee replacement.


The knee is the largest joint in the body and one of the most complex. It is made up of the femur (thighbone), tibia (shinbone) and patella (kneecap). Damage can result from injury, deformity or arthritis, when the articular cartilage that cushions the ends of the bones gradually erodes. Without this cushioning effect, the bones of the knee joint rub together. The knee can’t move easily and becomes stiff, swollen and painful.

In a partial knee replacement, only the damaged cartilage from the affected area is removed and replaced. The healthy cartilage and bone in the rest of the knee is left alone.

When is surgery recommended?

If you have knee pain that limits your everyday activities and all non-surgical methods of treatment have failed – including weight loss, anti-inflammatory medications, cortisone injections, lubricating injections and physical therapy – then you should consider knee replacement surgery.

Partial knee replacement is a worthwhile option for the right patient. Good candidates for this procedure are those with arthritis that is limited to one compartment of the knee who have tried all other conservative treatments. Patients with inflammatory arthritis, significant knee stiffness or ligament damage may not be ideal candidates.

Because proper patient selection is critical, it is important that each individual is carefully screened by an orthopedic surgeon to determine the most appropriate type of procedure.

What is the recovery time?

Minimally invasive approaches, improved implant material and design, and refined surgical techniques have dramatically reduced recovery time. For these patients, the typical recovery period is now weeks rather than months. Most patients are up and walking immediately following surgery and regain range of motion, strength and flexibility after several weeks of physical therapy. Hospital stays have been reduced to one or two days and the vast majority of patients can go directly home without having to use a rehabilitation center. As with all surgical procedures, specific recovery time varies by patient and demand.

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