What is a Total Knee Replacement?

A Total Knee Replacement (also called Total Knee Arthoplasty) 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.

Diagram of a total knee replacement

Diagram of a total knee replacement

Who should have a total knee replacement?

The most common reason for a Total Knee Replacement is severe pain and dysfunction caused by knee arthritis.

There are many types of arthritis but by far the most common type of arthritis that benefits from a Total Knee Replacement 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.

severe knee osteoarthritis

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 stength of the knee and the muscles around the knee
  • maintaining a healthy weight or loosing weight if necessary
  • some people gain benefit from using a knee brace

A Xray of the Right Knee with
No Arthritis

Xray of normal knee

A Xray of the Right Knee showing Osteoarthritis
Xray of knee with osteoarthritis

A Xray of a knee with a Total Knee Replacement
Xray of a total knee replacement ]

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 stength of the knee and the muscles around the knee
  • maintaining a healthy weight or loosing weight if necessary
  • some people gain benefit from using a knee brace

A knee replacement is often the best option if you have:

  • 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 15 – 20 years, so ideally, you have a total knee replacement that will last the rest of your life. If you are younger, Dr Tran may suggest other operations such as:
    • knee arthroscopy,
    • knee straigthening / realigning procedures called osteotomies
    • partial knee replacements
  • 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 alot of strain on your body. If you have conditions such as blocked arteries, diabetes, or are extremely obese, you have a increased risk of complications. There are some people who are not fit enough to have a knee replacement.

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.

A knee replacement may not remove all your pain or fully restore your knee movement, and it will not make your knee ‘brand new’ again. But it will considerably reduce your pain.

 

 

 

 

Latest advances in Knee Replacement technology

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 an improved quality of life.

There are a number of technological advances that have improved surgical precision. These include:

  • Computer Navigation
  • Patient Specific Instrumentation
  • Robotics

Computer Navigation

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, helping 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.

di-knee-navigation

Patient Specific Instrumentation (PSI)

A common alternative to computer navigation are patient specific implants where the alignment is assessed and calculated by computer tomography (CT) prior to surgery rather than intraoperative computer navigation or alignment jigs. The decision is based on patient anatomy and complexity of the surgery required.

Patient Specific Instrumentation (PSI) is designed to further improve knee replacements by enabling orthopaedic surgeons to customise 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 improve the results of knee replacement surgery.

PSI uses advanced imaging technology to generate one-time-use instruments specific to each patient. Several weeks prior to surgery, a computed tomography (CT) scan is taken of your knee. The scan is then used to build instrument guides that are manufactured for your individual knee.

di-knee-psi-kneereplacement1

di-knee-psi-kneereplacement2

di-knee-psi-kneereplacement3

How is a knee replacement performed?

The incision that 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

Preparing 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

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 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.