Total Knee Replacement (TKR)
What is total knee replacement?
Total knee replacement, also called total knee arthroplasty (TKA), is a surgical procedure in which the worn out or damaged surfaces of the knee joint are removed and replaced with artificial parts.
What are the indications for total knee replacement?
Total knee replacement surgery is commonly indicated for severe osteoarthritis of the knee. Osteoarthritis is the most common form of knee arthritis in which the joint cartilage gradually wears away. It often affects older people and younger people with a family history of knee arthritis or a past history of knee injury.
In a normal joint, articular cartilage allows for smooth movement within the joint, whereas in an arthritic knee the articular cartilage itself becomes thinner or completely worn away ("bone on bone";). In addition, the bones become thicker around the edges of the joint and may form bony "spurs";. All of these factors can cause pain and restricted range of motion in the joint as the joint capsule becomes
Your doctor may advise total knee replacement if you have arthritis associated with:
- Severe knee pain which limits your daily activities (such as walking, getting up from a chair or climbing stairs).
- Moderate to severe pain that occurs during rest or awakens you at night.
- Chronic knee inflammation and swelling that is not relieved with rest or medications
- Failure to obtain pain relief from medications, injections, physical therapy, or other conservative treatments.
- A severe bow-legged or knock knee deformity
What are the causes of osteoarthritis?
The exact cause of osteoarthritis is not known, however there are a number of factors that are commonly associated with the onset of arthritis and may include:
- Injury or trauma to the joint
- Fractures at the knee joint
- Increased body weight (if your BMI is 40 or >; you are 30x more likely to need a joint replacement than normal)
- Repetitive heavy manual overuse
- Joint infection
- Inflammation of the joint (such as Rheumatoid Arthritis or Gout)
- Connective tissue disorders
How is osteoarthritis diagnosed?
I will diagnose osteoarthritis of your knee based on your medical history, physical examination, and X-rays.
X-rays typically show a narrowing of the joint space in the arthritic knee.
How is total knee replacement surgery performed?
The goal of total knee replacement surgery is to relieve pain and restore the alignment and function of your knee.
The surgery is performed under spinal or general anaesthesia. I will make an incision in the skin over the affected knee to expose the knee joint. Then the damaged portions of the femur bone are cut at appropriate angles using specialized jigs customized to measurements that I make at the time of surgery (millimetre accurate). The femoral component is attached to the end of the femur usually without bone cement. I also cut the damaged area of the tibia. This removes the deformed part of the bone and any bony growths, and creates a smooth surface on which the implants can be attached. Next, the tibial component is secured to the end of the bone usually also without bone cement. Then a plastic piece called an articular surface is placed between the implants to provide a smooth gliding surface for movement. This plastic insert will support the body’s weight and allow the femur to move over the tibia, similar to the original meniscus cartilage. The femur and the tibia with the new components are then put together to form the new knee joint. To make sure the patella (knee cap) glides smoothly over the new artificial knee, its rear surface is also prepared to receive a plastic component if the patella is severely worn only. With all the new components in place, the knee joint is tested through its range of motion. The entire joint is then irrigated and cleaned with a sterile solution. The incision is carefully closed, drains are inserted and a sterile dressing is placed over the incision.
What post-operative care is necessary following the procedure?
Rehabilitation begins immediately following the surgery. A physiotherapist will teach you specific exercises to strengthen your leg and stretches to restore knee movement. You will be able to walk with sticks or a walker. A calf pump will be attacked to your lower leg to reduce DVT risks. A continuous passive motion (CPM) machine will be used to help you begin to move the knee joint. Continuous passive motion is a device attached to the treated leg which constantly moves the joint through a controlled range of motion, while the patient relaxes. Your physiotherapist will also provide you with a home exercise program to strengthen thigh and calf muscles and especially a stretching program and technique to regain the limits of knee movement as soon as possible. These stretches will NOT be easy and you MUST do them no matter how painful they are!
What are the risks and complications associated with total knee replacement?
As with any major surgery, possible risks and complications associated with total knee replacement surgery include:
- Knee stiffness (IF you do your stretches this risk is reduced. If you don’t do them you will have a stiff knee!)
- Blood clots (deep vein thrombosis) and secondary PE (pulmonary embolus)
- Nerve and blood vessel damage (VERY rare)
- Ligament injuries
- Patella (kneecap) dislocation
- Plastic liner wears out
- Loosening of the implant
If you find difficulty in performing simple activities such as walking or climbing stairs because of your severe arthritic knee pain, then total knee replacement may be an option for you. It is a safe and effective procedure to relieve pain, correct leg deformity, and help you resume your normal activities of daily living.
Data suggests that surgeons should do 80-100 cases per year of TKR to have the best results. Similar data suggests that surgeons with >8 years of Consultant practice have significantly better results that surgeons with < 8 years. (Consultant practice is Practice AFTER all training and Fellowships are completed)
Australian Orthopaedic Association National Joint Registry (AOANJRR) is a world leader in data on the success of Joint Replacement surgery. Every joint replacement done in Australia in the Public or Private system is logged into the registry. If the operation has to be redone for any reason anywhere in Australia (same surgeon or a different one) then that second operation is logged as a REVISION. A surgeon’s revision rate is largely a reflection of his/her skill in performing the operation AND selection of the best performing prostheses.
The Registry has data on over 500,000 joint replacements and surgeons can get an on-line report of their numbers of surgery per year and their revision rate compared with the national average of all other surgeons. . Both are important.
My data shows that I perform approximately 200 knee replacements per year. In fact, I have performed the 9th highest number of joint replacements recorded nationally in the AOANJRR.
My revision rate is half (1/2) the national average for all other surgeons who do knee replacements.
You should not have a knee replacement by a surgeon who is unwilling to share their AOANJRR data with respect to how many they do per year and their recorded revision rate.
NOTE: there is no joint registry data in the world showing that robotic surgery has any advantages over conventional skilled experienced surgery. I do not use Robotic Surgery at this stage of its early development for very good reasons that I will discuss with you verbally.