Total knee replacement: Everything you need to know

Total knee replacement, also known as knee arthroplasty, is a common and highly effective surgical procedure for patients with severe knee joint damage.

Here, Mr Amit Bishnoi, renowned consultant orthopaedic surgeon, offers an expert insight into total knee replacement, including the pre-operative requirements, the surgical process, and the longevity of the procedure.

When is total knee replacement recommended?

Total knee replacement is typically recommended for patients experiencing significant knee pain and functional limitations due to advanced joint diseases, such as osteoarthritis, rheumatoid arthritis, and post-traumatic arthritis.

For these patients, total knee replacement surgery is indicated when:

• Conservative treatments like medications, physical therapy, and joint injections have failed.
• Pain interferes with daily activities such as walking, climbing stairs, and getting in and out of chairs.
• Pain persists while resting, either during the day or night.
• There is chronic knee inflammation and swelling that doesn’t improve with rest or medications.
• There is significant knee stiffness and limited range of motion.

Are there any pre-operative tests or evaluations required before the surgery?

Before undergoing total knee replacement, the surgeon will review the patient’s medical history, including previous surgeries, current medications, and any chronic conditions. A physical examination of the knee will then assess the range of motion, strength, and alignment.

As well as this, other pre-operative tests will include:

• Imaging tests: X-rays are typically used to determine the extent of damage and deformity in the knee joint. MRI scans may be performed to evaluate the condition of the soft tissues, such as ligaments and menisci.
• Blood tests: Blood tests help to identify any underlying health issues that need to be managed before surgery, such as anaemia or infections.
• Joint aspiration: In some cases, fluid may be drawn from the knee joint to check for infection or inflammation.

How is total knee replacement surgery performed?

Total knee replacement surgery involves removing the damaged parts of the knee joint and replacing them with artificial components. The surgery is performed under either general anaesthesia or regional anaesthesia (spinal or epidural), depending on the patient’s health and the surgeon's recommendation.

During total knee replacement, a surgical incision - typically around 6 to 10 inches long - will be made on the front of the knee to access the joint. The surgeon will meticulously remove the damaged sections of the femur (thigh bone) and tibia (shin bone), along with a small amount of underlying bone. If the patella (kneecap) is affected, it will also be resurfaced.

The removed bone and cartilage will then be replaced with metal components (implant), usually made of titanium or cobalt-chromium alloys, that recreate the joint surfaces. A plastic spacer made of polyethylene will also be inserted between the metal components to ensure smooth movement of the joint. If the kneecap is resurfaced, a plastic button will be attached to its underside to allow it to glide smoothly over the new joint.

Following this, the surgeon will ensure that the components are aligned correctly and that the joint is balanced. The surgical incision will be closed with sutures or staples, and the knee will be bandaged. In some cases, a drain may be placed to remove excess fluid from the joint area.

Post-surgery, the patient will be moved to a recovery room for monitoring. Pain management will be provided, and physical therapy will typically begin within 24 hours of the surgery to promote mobility and reduce the risk of complications.

What are the potential risks and complications associated with total knee replacement surgery?

While total knee replacement is generally safe, it carries potential risks and complications like any major surgery.

Risks and complications may include:

• Infection: Post-surgical infection can occur at the incision site or deep within the new joint. This may require additional surgery and antibiotics.
• Blood clots: Blood clots can develop in the veins of the legs (deep vein thrombosis) or travel to the lungs (pulmonary embolism). Blood-thinning medications are often prescribed to prevent this.
• Stiffness: Some patients can experience stiffness and limited movement post-surgery, which may require physical therapy or additional interventions.

How long can I expect my total knee replacement to last?

The longevity of a total knee replacement can vary based on several factors, including the patient’s activity level, weight, and overall health.

Most knee replacements last between 15 to 20 years. Patients who undergo knee replacement at a younger age may need revision surgery at some point due to the longer duration of implant use and higher activity levels. Adhering to post-operative care instructions, including physical therapy, and maintaining a healthy weight can enhance recovery and extend the life of the implant.

If you would like to schedule an appointment with Mr Amit Bishnoi, head on over to his Top Doctors profile today.