What is Partial Knee Replacement?

Partial Knee Replacement (PKR), also known as unicompartmental knee arthroplasty, is a surgical procedure designed to replace only the damaged portion of the knee joint, rather than the entire knee. This procedure is often an option for individuals who have damage limited to a specific area of the knee, most commonly due to osteoarthritis. Unlike total knee replacement, partial knee replacement preserves more of your natural knee structure and function.

Who is a Candidate for Partial Knee Replacement?

Partial knee replacement may be a suitable option if you:

• Experience pain primarily in one compartment of the knee (medial, lateral, or patellofemoral).
• Have good range of motion in your knee with relatively intact ligaments.
• Have not responded well to other treatments such as medications, injections, or physical therapy.
• Are active but suffering from limited mobility and pain in a specific part of the knee joint.

Your doctor will assess the condition of your knee through physical exams, imaging tests, and discussion of your symptoms to determine whether partial knee replacement is the right option for you.

Benefits of Partial Knee Replacement

Partial knee replacement offers several advantages over total knee replacement, including:

• Faster Recovery: Since only part of the knee is replaced, recovery time is typically shorter, allowing you to return to daily activities sooner.
• Less Invasive: The surgery requires a smaller incision, which means less damage to healthy tissue and a reduced risk of complications.
• More Natural Knee Function: PKR preserves the unaffected parts of the knee, resulting in more natural movement and better knee function compared to total knee replacement.
• Reduced Pain: Patients often experience less postoperative pain and swelling.

The Partial Knee Replacement Procedure

1. Preoperative Assessment: Your surgeon will evaluate the extent of damage in your knee, focusing on whether it is limited to a specific compartment. Imaging tests like X-rays or MRI scans are often used to confirm the diagnosis.
2. During Surgery: The surgeon will make a small incision over the affected area of the knee. The damaged cartilage and bone in the affected compartment are removed, and an implant made of metal and plastic is inserted to replace the worn-out portion. The remaining parts of the knee joint remain intact.
3. Duration: The procedure typically lasts between 1 to 2 hours and is performed under general or regional anesthesia.

Recovery and Rehabilitation

Recovery from partial knee replacement is typically quicker than from total knee replacement. Most patients can begin walking on the day of surgery or the next day, and physical therapy will help strengthen the knee and restore range of motion. Most people can return to normal activities within 4 to 6 weeks, although full recovery may take a bit longer depending on individual factors.

Potential Risks and Complications

While partial knee replacement has a high success rate, it still carries some risks, including:

• Infection
• Blood clots
• Stiffness or difficulty moving the knee
• Implant loosening or wear over time
• Need for further surgery (such as total knee replacement) if arthritis progresses in other parts of the knee

However, most patients experience significant relief from knee pain and improved mobility following the procedure.

Comparing Partial and Total Knee Replacement

Partial Knee Replacement	Total Knee Replacement
Replaces only one part of the knee	Replaces the entire knee joint
Smaller incision and less invasive	Larger incision and more extensive surgery
Faster recovery and rehabilitation	Longer recovery period
More natural knee movement	May feel less “natural”
Limited to certain patients	Suitable for widespread arthritis or joint damage

Is Partial Knee Replacement Right for You?

You may be a candidate for partial knee replacement if your arthritis is confined to one part of the knee and your knee ligaments are still functional. PKR is generally recommended for patients with milder arthritis and those who are active and in good overall health.

Frequently Asked Questions

1. How long does a partial knee replacement last? On average, partial knee replacements can last 10 to 15 years. The longevity of the implant depends on activity levels, weight, and overall health.
2. Will I need a total knee replacement in the future? If arthritis progresses in other parts of the knee, you may eventually require a total knee replacement, but many patients are satisfied with the results of a partial knee replacement for many years.
3. How soon can I return to normal activities? Most patients are able to resume normal activities within 4 to 6 weeks, with some even returning to work and light activities sooner. Strenuous activities may need to be delayed for several months.
4. Is the recovery painful? As with any surgery, there will be some discomfort during the recovery process, but pain is usually well-managed with medications and physical therapy.