A Total Knee Replacement (also called Total Knee Arthroplasty) is a surgical procedure designed to replace the severely diseased knee joint with an artificial knee joint.
It involves removing parts of your femur (thigh bone), tibia (shin bone) and patella ( kneecap) and replacing them with a combination of surgical-grade metal alloys and highly wear-resistant plastic.
It’s designed to help with pain and restore the bending movement of the knee.
What should I expect from knee replacement surgery?
A knee replacement can dramatically reduce the pain caused by arthritis and get you walking and bending your knee again.
However, a knee replacement is not expected to remove all your pain or fully restore your knee movement.
Most knee replacements last more than 20 years, and knee designs and techniques are constantly improving with medical advances.
Who should have a total knee replacement?
The most common reason for a Total Knee Replacement is severe pain and stiffness caused by knee arthritis.
There are many types of arthritis but by far the most common type of arthritis is Osteoarthritis, followed by Rheumatoid Arthritis.
Osteoarthritis is a wear and tear process that happens with aging but can also occur after an injury to the knee joint.
If you are considering total knee replacement surgery, you should have first tried non-surgical methods to help you with your knee pain.
These include:
- pain medications
- using a walking stick or other walking aid
- exercises to maintain the movement and strength of your knee
- maintaining a healthy weight or loosing weight
- some people gain benefit from using a knee brace
An X-ray of the Right Knee with
No Arthritis
An X-ray of the Right Knee Showing Osteoarthritis
An X-ray of a Knee with a Total Knee Replacement
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Once you have tried all the non-surgical options, and are still in severe pain. Then a knee replacement can be a very good option to get you moving again and reduce your pain.
If you are considering a knee replacement, as a guide you should be experiencing:
- Severe pain. A knee replacement is a big operation and should only be considered if the pain in your knee is severe. For example, your pain should make it difficult to walk, climb stairs and perform your activities at home.
- Severe dysfunction. Your knee pain should be affecting your mobility and often causes stiffness and prevent you from fully bending or straightening your knee.
- Tried other ways of controlling your pain. You’ve tried other methods to improve symptoms, for example, resting, weight loss, physiotherapy, a cane or other walking aid, medications and knee braces, but they’ve failed.
- Be old enough. It is best to perform a knee replacement when your older, for example over 60. This is because knee replacements can wear out and eventually fail. Total knee replacements often last over 20 years, so ideally, you have a total knee replacement that will last the rest of your life. Also, young physically active people are much more likely to prematurely wear out the Total knee replacement.
- Be fit enough for the operation. A knee replacement is major surgery and can put a lot of strain on your body. If you have conditions such as blocked arteries, diabetes, or are extremely obese, you have an increased risk of complications. There are some people who are suitable for a knee replacement because of their general health
Latest advances in Knee Replacement technology
Personalised knee replacements using CT scan analysis of your knee and kinematic technology
Everyone has unique anatomy. Modern technology allows us to match your knee replacement to your native knee, personalising the position to best suit your knee.
During a joint replacement procedure, it is important that everything is aligned precisely. Accurate alignment of the knee components is critical to the overall function of your new joint and it also plays a role in helping your joint feel healthy again and helping the joint replacement to potentially last longer.
Why is an accurately implanted knee replacement necessary?
Implant misalignment, even if only by a few degrees, requires some patients to have additional surgery within a few years, either to reduce discomfort or to replace the worn implant. For most patients, the most dramatic benefit of a well-aligned implant is the return to normal mobility and improved quality of life.
There are a number of technological advances that have improved surgical precision. These include:
- Computer Navigation
- Patient Specific Instrumentation
- Robotics
Patient-Specific Instrumentation (PSI)
A CT scan is performed and uploaded to 3D imaging software. The scan is then used to build instrument guides that are manufactured for your individual knee.
Patient-Specific Instrumentation (PSI) is designed to further improve knee replacements by enabling orthopaedic surgeons to customise the surgery to a patient’s individual anatomy.
The goal is a procedure that reduces the risk of knee replacement malpositioning, increases alignment accuracy of the knee replacement, and therefore hopefully improves the results of knee replacement surgery.
Computer Navigation technology uses special tracking devices, providing a comprehensive understanding of your joint mechanics in the operating room. Armed with this information, adjustments within a fraction of a degree help to ensure your new joint has the stability and range of motion needed for a successful replacement. Specifically, the technology uses the latest advancements in science and computer engineering to make the procedure more accurate than joint surgery without it.
As an instrument is moved within your joint, special infrared trackers calculate its position and wireless instruments instantaneously transfer the data to a computer. This information is then displayed on a monitor as an interactive model of the anatomy or “blueprint” that supplies all the angles, lines and measurements of your unique anatomy. Your diseased bone is then replaced with new, artificial joint components.
How is a knee replacement performed?
The incision is usually around 15 – 25 cm long and runs straight down the middle of the front of your knee.
Precise surgical bone cuts are made at the end of your femur (thigh bone) and the top of your tibia (shin bone), thereby removing your arthritic knee joint.
The knee replacement is made of surgical-grade metal alloy and plastic.
It is inserted and held in place either by surgical cement or by a special coating on the metal.
The operation usually takes about 90 minutes.
At the time of surgery and for a short period after your surgery, you will be given antibiotics and medications to thin your blood in order to prevent blood clots.
Preparing for a Knee Replacement
Before your operation, your fitness for the operation will be assessed by our peri-operative physician and all the necessary tests performed in preparation for the operation.
Tests
Tests that may be ordered for you include:
- blood tests: FBE, U&E
- Xray of your knee
- Urine Test
- ECG
- CT Scan of your knee if you are having a Patient Specific Instrumentation (PSI) knee replacement or Robotic Assisted Knee Replacement
Prepare your skin
Your skin should not have any infections or irritations before surgery. If either is present, please let us know.
Medications
Our physician will advise you which medications you should stop or can continue taking before surgery.
Go see your dentist
Consider getting treatment for significant dental diseases (including tooth extractions and periodontal work) before your knee replacement surgery. Routine cleaning of your teeth should be delayed for several weeks after surgery.
Get some help from your friends and family
Although you will be able to walk with crutches or a walker soon after surgery, you will need some help for several weeks with such tasks as cooking, shopping, bathing, and laundry. If you live alone, then a stay at Rehab can be arranged.
Home planning
The following is a list of home modifications that will make your return home easier during your recovery:
- Securely fastened safety bars or handrails in your shower or bath
- Secure handrails along all stairways
- A stable chair for your early recovery with a firm seat cushion (that allows your knees to remain lower than your hips), a firm back, and two arms
- A raised toilet seat
- A stable shower bench or chair for bathing
- A long-handled sponge and shower hose
- A dressing stick, a sock aid, and a long-handled shoe horn for putting on and taking off shoes and socks without excessively bending your new knee
- A reacher that will allow you to grab objects without excessive bending of your knees
- Removal of all loose carpets and electrical cords from the areas where you walk in your home
Prehab - Exercises to prepare for surgery
Recovering after a Knee Replacement
After the operation, the nursing staff will closely watch you until you have recovered from the anaesthetic. You will then go back to the ward where a team of nurses and physiotherapists will help you recover from your operation.
The usual stay in the hospital is 3-5 days.
Complications
The risks and complications of a knee replacement include:
- Infection. Wound infection occurs in about 1 in 100 people. Infection is a major complication and may require further surgery and possibly the new knee joint to be removed.
- Deep Vein Thrombosis and Pulmonary Embolism. Blood clots can form in the legs after surgery. The clots can break off and travel to the lungs and can cause death.
- Wear and tear. The artificial joint may fail or wear out. Surgical revision of the knee joint replacement may be required.
- Dislocation of the knee joint The knee joint/patella can dislocate because muscles and ligaments have not yet repaired themselves to provide support to the joint.
- Numbness. Numbness at the side of the cut can happen. This may be temporary or permanent.
- Nerve damage. Damage to the nerves may cause a burning pain and inability to straighten the leg.
- Stiffness. Stiffness of the knee after the surgery can cause difficulty in walking and sitting and pain on movement. Manipulation and possibly further surgery may be required.
- Fracture. The bones around the joint may break during or after surgery.
- Death. Death is extremely rare due to knee replacement.