Understanding the Difference Between Unicompartmental and Total Knee Replacement

When you first consider knee replacement surgery, it's natural to come across two main types of procedures: total knee replacement (TKR) and unicompartmental knee replacement (UKR). Both aim to relieve pain and improve function, but they differ significantly in approach, suitability, and recovery. So, which one is right for you?

The Knee's Structure: Three Compartments The knee joint consists of three key compartments:

1. The medial compartment (inner side of the knee)

2. The lateral compartment (outer side of the knee)

3. The patellofemoral compartment (front of the knee, around the kneecap)

Arthritis can affect one, two, or all three of these compartments. Understanding which part of your knee is damaged is key to determining which surgery might be appropriate.

Unicompartmental Knee Replacement (UKR)

A partial or unicompartmental knee replacement targets only one of the three knee compartments. For patients with arthritis in just one part of the knee (often the medial compartment), UKR can provide relief while preserving healthy tissue in the other compartments. This surgery replaces only the damaged part with a metal and plastic prosthetic, leaving the rest of the knee intact.

Why Choose UKR?

• Smaller procedure: Since only part of the knee is replaced, UKR involves less disruption of healthy tissue, making it a less invasive surgery.

• Quicker recovery: UKR typically results in a faster recovery time and shorter hospital stays compared to total knee replacement.

• Preservation of natural function: Because more of your natural knee is retained, many patients report a more natural feeling post-surgery. Additionally, the ligaments (including the crucial ACL) are often preserved, resulting in better movement and functionality.

• Lower complication rates: Studies show that partial knee replacements generally carry lower risks of complications like infection and blood clots compared to total knee replacement.

Who is a Good Candidate for UKR?

Ideal candidates for UKR are patients with arthritis confined to just one compartment of the knee, good ligament function, and minimal knee deformity. If you have good bone structure and haven’t experienced significant deformities or severe wear in your knee, you may be considered for this procedure. Additionally, studies suggest that age is no longer a strict barrier – both younger and older patients can benefit from UKR.

However, it’s important to remember that partial knee replacements may not last as long as total knee replacements. Over time, you might need a total knee replacement if arthritis progresses in the other compartments.

Total Knee Replacement (TKR)

A total knee replacement involves replacing the entire knee joint, including the femur, tibia, and patella (kneecap). This surgery is recommended when arthritis affects multiple compartments or when the knee has become severely damaged or deformed.

Why Choose TKR?

• Comprehensive solution: If arthritis is widespread, or if there is significant knee deformity, total knee replacement can provide a more complete solution to pain and loss of mobility.

• Longer lifespan: A total knee replacement typically lasts longer than a partial knee replacement (15-20 years compared to 10-15 years for partials).

• Restoration of knee function: Although a total knee may feel artificial, it can dramatically improve the quality of life, providing relief from pain and restoring the ability to move more freely.

Who is a Good Candidate for TKR?

If you have arthritis affecting all parts of your knee joint, if the knee is deformed, or if you are unable to fully straighten your leg, a total knee replacement is likely the right option. For people with advanced arthritis, the procedure can significantly reduce pain, improve mobility, and restore quality of life. However, the recovery is more intensive and typically involves longer hospital stays and rehabilitation.

Which is Right for You?

The choice between UKR and TKR depends on several factors, including the extent of your arthritis, the overall health of your knee joint, and your lifestyle. As a consultant, I will assess these factors in detail during your consultation to help guide you toward the most appropriate option for your needs.

If you have arthritis confined to one compartment and your knee is relatively stable, you may be a candidate for UKR. However, if the damage is more widespread or your knee is deformed, a total knee replacement may be necessary to restore function and reduce pain.

Both surgeries offer excellent outcomes for the right patients, and your recovery journey will involve working closely with physiotherapists to help you regain strength, mobility, and flexibility in your knee.

If you're considering knee replacement surgery, I recommend scheduling a consultation so we can discuss your specific condition and the best treatment options for you. I'm here to guide you through the process every step of the way.