Partial vs total knee replacement: Which one is better for you?

Knee replacement surgery is a common and effective solution for people with chronic knee pain or mobility issues due to arthritis, injury, or general wear-and-tear. However, deciding between a partial knee replacement and a total knee replacement can be difficult. This article provides an expert insight into both procedures.

When are a partial and a total knee replacement recommended?

A partial knee replacement is recommended when only one of three compartments of the knee (medial, lateral, or patellofemoral) is damaged. This surgery is ideal for people with localised osteoarthritis, where the damage is confined to just one part of the knee.

A total knee replacement, on the other hand, is recommended when all three components of the knee are affected, usually by arthritis or joint injury. This surgery is usually a better option if the damage is more widespread or if deformities and significant cartilage loss are present.

Above all, it’s crucial to consult with your orthopaedic surgeon, who will evaluate your specific condition and recommend the best surgical option for you.

How are a partial and a total knee replacement performed?

Partial knee replacement

In a partial knee replacement, only the damaged portion of the knee is removed and replaced with a metal or plastic implant (also known as a prosthesis). The healthy bone, cartilage, and ligaments are preserved.

On the day of the procedure, your surgeon will first make a small incision (typically 7cm long) over the damaged part of the knee. Your surgeon will then expose the knee joint and remove the damaged cartilage and bone from the affected compartment.

Subsequently, specialised tools will be used to precisely shape the femur and tibia to prepare them for the prosthesis. Your surgeon will then insert a metal prosthetic component on the end of the femur and another metal or plastic prosthetic component on the end of the tibia. These components will replace the removed tissue and bone, mimicking the natural shape of the joint.

Once the prosthetic components are in place, your surgeon will bend and straighten the knee to ensure that the joint functions properly, with smooth and stable motion. Your surgeon will then secure the incision with sutures or staples.

Total knee replacement

In a total knee replacement, the entire knee joint is substituted. This includes removing and replacing damaged cartilage in the medial, lateral, and patellofemoral compartments.

On the day of the procedure, your surgeon will first make a vertical incision, typically 15cm long, along the front of the knee and then carefully move the patella to the side to expose the joint beneath. Next, your surgeon will remove the damaged cartilage surfaces from the femur, tibia, and patella.

Specialised tools will be used to shape the femur, tibia and patella to accommodate the prosthesis, which will replace all the damaged cartilage and bone in the knee to restore function. Once the prosthesis is in place, your surgeon will test the knee’s range of motion and alignment, ensuring that it moves smoothly and that the ligaments are properly balanced. If necessary, your surgeon will adjust the soft tissues around the knee to improve alignment and stability.

Your surgeon will lastly close the incision using sutures or staples. In some cases, a drain will be inserted to remove excess blood or fluid from the surgical site, and the knee will be covered with a sterile bandage.

Are there any risks associated with either surgery?

As with any surgery, both partial and total knee replacements come with potential risks.

Risks of partial knee replacement include: infection, limited range of motion or knee stiffness, arthritis progression to the remaining healthy part of the knee, and the implant loosening over time. Risks of total knee replacement include: infection, blood clots, nerve damage, persistent stiffness, and implant wear over time.

However, these risks are generally rare and your surgeon will take preventive measures to minimise them.

What does recovery involve for both a partial and a total knee replacement?

People undergoing partial knee replacement will generally recover more quickly than those having total knee replacement. While full recovery takes around 3 months, many will resume light activities within 3 to 6 weeks.

On the other hand, recovery from a total knee replacement is more extensive and with a much longer rehabilitation phase. Full recovery usually takes 3 to 6 months, with further improvements often continuing for up to a year.

How long do partial and total knee replacement implants last?

Partial knee replacements generally last around 10 to 15 years. However, factors such as age, activity level, and the progression of arthritis can affect the implant's lifespan. People under 55 will eventually need revision surgery.

Total knee replacements generally last longer, with most implants lasting 15 to 20 years or more. Advances in materials and techniques have greatly improved their durability, allowing many people to enjoy over two decades of pain relief before needing revision surgery.