A partial knee replacement is an alternative to total knee replacement for some patients with osteoarthritis of the knee. This surgery can be done when the damage is confined to a particular compartment of the knee.

In the past, partial knee replacement was reserved for older patients who were involved in few activities. Now, partial knee replacement is often preferred in the younger population as their recovery is quicker and often with much less pain. About 5% to 6% of patients with arthritic knees are estimated to be eligible for partial knee replacement.

What is osteoarthritis?

Osteoarthritis is the wearing away of the connective tissue, called articular cartilage, within the joint. Articular cartilage prevents one bone from scraping against another. The cartilage acts as a shock absorber in the joint and allows for smooth and stable movement within the joint. When the cartilage thins, the joint can inflame and you may feel pain and stiffness in the joint. Your range of motion may be limited.

How common is knee osteoarthritis?

Up to 30% of the population is believed to have knee osteoarthritis. Until age 50, knee osteoarthritis is equally common in men and women. After age 50, more women are affected.

What is a partial knee replacement?

In a partial knee replacement, only the damaged part of the knee cartilage is replaced with a prosthesis.

Who is a candidate for partial knee replacement?

Patients with medial, or lateral, knee osteoarthritis can be considered for partial knee replacement. "Medial" refers to the inside compartment of the joint, which is the compartment nearest the opposite knee, while "lateral" refers to the outside compartment farthest from the opposite knee. Medial knee joint degeneration is the most common deformity of arthritis.

Other factors to consider:

  • You may want to consider a knee replacement if your knee pain persists despite your taking anti-inflammatory drugs and maintaining a healthy weight.
  • Your doctor will ask you to identify the area of pain in your knee, then check your range of motion and the knee's stability. An X-ray of the knee will determine your eligibility for partial knee replacement. However, your surgeon may not know for certain if you are a good candidate until the surgery has begun.
  • You must have an intact anterior cruciate ligament, a sufficient range of knee motion, damage to only one compartment, and a stable knee. The angulation of the deformity is also considered.
  • In the past, a partial knee replacement was considered only in patients older than 60 years who were sedentary but younger, more active patients are increasingly being considered.