Unicompartmental Knee Arthroplasty (UKA)

Unicompartmental knee arthroplasty, also known as partial knee replacement, is a surgical procedure used to treat arthritis that is limited to a single compartment of the knee. The goal of UKA is to relieve pain and restore function in the affected knee.

Indications

UKA is typically recommended for patients with:

• Severe osteoarthritis or avascular necrosis limited to one compartment of the knee (medial, lateral, or patellofemoral)
• Mild to moderate arthritis in other compartments
• Intact ligaments and stable knee joint
• Failed conservative treatment options, such as physical therapy, medications, and injections

Surgical Procedure

The UKA procedure involves the following steps:

1. A small incision (usually 3-4 inches) is made in the affected knee to access the damaged compartment
2. The surgeon removes the damaged cartilage and bone, and prepares the joint surface for the implant
3. A metal and plastic implant is inserted into the prepared joint space, which replaces the damaged compartment
4. The implant is secured with cement or a press-fit technique
5. The incision is closed, and the knee is dressed with a bandage or splint

Types of Implants

There are several types of implants used in UKA, including:

• Fixed-bearing implants: These have a fixed bearing surface that moves with the femur (thigh bone)
• Mobile-bearing implants: These have a mobile bearing surface that allows for more natural movement
• Customized implants: Some surgeons use customized implants that are designed to fit the individual patient's anatomy

Benefits and Advantages

The benefits of UKA include:

• Less tissue damage and trauma compared to total knee arthroplasty (TKA)
• Smaller incision and less blood loss
• Faster recovery time, with most patients able to bear weight and walk within a few days
• More natural feeling and movement in the knee joint
• Lower risk of complications, such as infection and blood clots

Risks and Complications

As with any surgical procedure, there are risks and potential complications associated with UKA, including:

• Infection
• Blood clots
• Nerve damage
• Bone fracture
• Loosening or wear of the implant
• Persistent pain or stiffness

Recovery and Rehabilitation

The recovery process for UKA typically involves:

• Immediate post-operative care, including pain management and wound care
• Physical therapy to restore range of motion, strength, and function in the knee joint
• A gradual return to normal activities, including walking, climbing stairs, and light exercise
• Follow-up appointments with the surgeon to monitor progress and remove sutures or staples

Outcomes and Prognosis

The outcomes of UKA are generally excellent, with most patients experiencing significant improvement in pain and function. Studies have shown that:

• 90-95% of patients report good to excellent results at 5-10 years after surgery
• 80-90% of patients are able to return to normal activities, including sports and heavy labor
• The implant survival rate is high, with 90-95% of implants still functioning well at 10-15 years after surgery