Unicondylar knee arthroplasty, also known as partial or unicompartmental knee replacement, is a less invasive alternative to total knee arthroplasty. This procedure is designed to replace only the portion of the knee that has been damaged by arthritis, leaving the healthier areas intact. Patients who undergo unicondylar knee arthroplasty typically experience less scarring, shorter recovery times, and a greater range of motion compared to those undergoing total knee replacement.

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Candidates for a Unicondylar Arthroplasty

While most candidates for unicondylar knee arthroplasty are over the age of 55, younger patients with significant knee damage may also be considered for the procedure if they are experiencing debilitating symptoms. Ideal candidates are individuals whose arthritis is confined to one area of the knee, typically the medial (inner) or lateral (outer) compartment. Additionally, patients with intact ligaments and no significant deformities are more likely to benefit from partial knee replacement.

Before recommending a unicondylar knee arthroplasty, the surgeon will conduct a thorough physical examination to pinpoint the exact location of the pain and confirm that the damage is localized. Imaging tests such as X-rays and MRI scans will be performed to assess the extent of cartilage damage and guide the surgical decision-making process.

The Unicondylar Arthroplasty Procedure

Unicondylar knee arthroplasty is typically performed under general or spinal anesthesia and generally takes between 1 to 2 hours. The surgeon makes an incision in the front of the knee near the affected area. This incision allows the surgeon to carefully examine the knee’s internal structures and confirm that the arthritis is localized to a single compartment. If the damage affects multiple areas of the knee, a total knee arthroplasty may be recommended instead.

If the arthritis is confined to one region of the knee, the surgeon proceeds with the unicondylar replacement. This involves removing the damaged cartilage and bone from the femur (thigh bone) and tibia (shin bone) in the affected area. The excised portions are replaced with metal prosthetics that are secured with cement. A plastic insert is placed between the metal components to allow for smooth and fluid motion of the knee joint following the procedure.

Recovery from a Unicondylar Arthroplasty

Recovery from a unicondylar knee arthroplasty is typically shorter and more comfortable compared to total knee replacement due to the less invasive nature of the procedure. While the procedure requires a hospital stay of 1 to 3 days, the smaller incision and reduced tissue trauma generally lead to faster healing.

During the initial recovery phase, most patients will need to use crutches or a walker for the first week or two to avoid placing excess weight on the healing knee. Physical therapy is an essential part of the recovery process, helping the knee regain strength, flexibility, and function. Many patients fully recover within 6 weeks and can return to regular activities, including low-impact sports.

Risks of a Unicondylar Arthroplasty

While unicondylar knee arthroplasty is considered a safe and effective procedure, like all surgeries, it carries some risks. Possible complications include:

  • Infection
  • Blood clots
  • Damage to blood vessels or nerves
  • Persistent knee pain

However, due to the less invasive nature of partial knee replacement, the risk of complications is generally lower compared to total knee replacement. Overall, unicondylar knee arthroplasty offers a highly effective solution for individuals with localized knee arthritis, providing significant pain relief and improved function.

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