Knee Replacement

Knee Replacement

Article by John Miller

What is a Knee Replacement?

Knee Replacement Surgery

Knee replacement, or knee arthroplasty, is a surgical procedure to replace the weight-bearing surfaces of the knee joint to relieve pain and disability. It is most commonly performed for osteoarthritis and other knee diseases such as rheumatoid arthritis and psoriatic arthritis.

Knee replacement surgery can be performed as a partial or a total knee replacement. In general, the surgery consists of replacing the diseased or damaged joint surfaces of the knee with metal and plastic components shaped to allow continued motion of the knee.

What Causes Knee Joint Deterioration?

Knee arthritis (inflammation of your knee joint) is a major cause of knee joint deterioration. The most common arthritis is osteoarthritis, which is inflammation related to wear and tear of the knee joint.

Wearing your knee joint is a common problem with ageing. However, certain conditions can accelerate the process of wear.

Injury to your knee joint, surgical procedures, muscle weakness or increased body weight all accelerate the load and hence the wear and tear of the knee joint.

Rheumatoid disease, gout or infection can also increase your joint wear and tear.

Interesting fact: If you lose just 10 kilograms of weight, you can reduce the load on your knees by half!

What are the Symptoms of Knee Joint Arthritis?

The obvious sign of wear and tear of the knee joint is pain. Knee pain can be achy or sharp and may be accompanied by swelling.

Because your knees do not wear equally across the joint surface, a deformity may begin to appear over time. This can be both knock-kneed or bow-legged in appearance or windswept knees (one of each).

You may also find one or both knees lacking full movement, especially extension.

How is Knee Arthritis Diagnosed?

On examination, your physiotherapist or doctor will look for signs of limited knee movement and deformity, swelling and, importantly, knee pain. In most cases, an X-ray will be sufficient to show the degree of wear and tear. An MRI may also be used to exclude soft tissue pathology.

Please arrange an appointment with your trusted healthcare professional with a special interest in knees for specific advice.

What is the Treatment for Total Knee Replacement?

Pre Operative Physiotherapy

Pre-operatively you may be prescribed a course of physiotherapy to prepare better your knee and its surrounding muscles for the upcoming surgery.

Studies indicate that the better your muscle strength and knee range of movement before surgery, the better your recovery.

Post Operative Physiotherapy

Many patients with a Total Knee Replacement (TKR) start to feel better within a few weeks of the surgery.

Post-operative physiotherapy is important to regain full knee motion, strength and day to day function.

Your post-operative physiotherapy treatment will aim to:

  • Reduce knee pain and inflammation.
  • Normalise knee joint range of motion.
  • Strengthen your knee muscles: quadriceps (esp VMO) and hamstrings.
  • Strengthen your lower limb: calves, hip and pelvis muscles.
  • Improve patellofemoral (knee cap) alignment
  • Normalise your muscle lengths
  • Improve your proprioception, agility and balance
  • Improve your technique and function, e.g. walking, stair climbing, squatting and bending
  • Minimise your chance of re-injury.

Risks of Knee Replacement Surgery

Risks of knee replacement surgery include infection, persistent instability and knee pain, knee stiffness, and difficulty returning to your previous level of activity. The good news is that better than 90% of patients have no complications post-surgery.

Interesting Fact

The first Total Knee Replacement (TKR) was pioneered by Leslie Gordon Percival Shiers (FRCS) in 1954. He refused to patent his invention but rather allow other surgeons to modify and improve on his ideas.

Return to Activity Post-Total Knee Replacement

You can return to most activities following a successful knee replacement. Unfortunately, because of the nature of the knee prosthesis, it is currently not recommended to return to high impact activities such as running and jumping. Less high impact sports such as golf, bowls or swimming are encouraged.

Your knee physiotherapist will guide you. Please seek their advice.

Common Causes - Knee Pain

Knee pain can have many origins from local injury, referred pain, biomechanical issues and systemic issues. While knee pain can appear simple to the untrained eye, a thorough assessment is often required to ascertain the origin of your symptoms. The good news is that once a definitive diagnosis is determined, most knee pain quickly resolves with the correct treatment and rehabilitation.

Knee Ligament Injuries

Knee Meniscus Injuries

Kneecap Pain

Knee Arthritis

Knee Tendon Injuries

Muscle Injuries

Knee Bursitis

Children’s Knee Conditions

Other Knee-Related Conditions

Knee Surgery

Knee FAQs

For specific information regarding your knee pain, please seek the assistance of a healthcare professional with a particular interest in knee condition, such as your knee physiotherapist.

Acute Injury Signs

Acute Injury Management.

Here are some warning signs that you have an injury. While some injuries are immediately evident, others can creep up slowly and progressively get worse. If you don't pay attention to both types of injuries, chronic problems can develop.

For detailed information on specific injuries, check out the injury by body part section.

Don't Ignore these Injury Warning Signs

Joint Pain

Joint pain, particularly in the knee, ankle, elbow, and wrist joints, should never be ignored. Because these joints are not covered by muscle, pain here is rarely of muscular origin. Joint pain that lasts more than 48 hours requires a professional diagnosis.


If you can elicit pain at a specific point in a bone, muscle, or joint, you may have a significant injury by pressing your finger into it. If the same spot on the other side of the body does not produce the same pain, you should probably see your health professional.  


Nearly all sports or musculoskeletal injuries cause swelling. Swelling is usually quite obvious and can be seen, but occasionally you may feel as though something is swollen or "full" even though it looks normal. Swelling usually goes along with pain, redness and heat.

Reduced Range of Motion

If the swelling isn't obvious, you can usually find it by checking for a reduced range of motion in a joint. If there is significant swelling within a joint, you will lose range of motion. Compare one side of the body with the other to identify major differences. If there are any, you probably have an injury that needs attention.


Compare sides for weakness by performing the same task. One way to tell is to lift the same weight with the right and left sides and look at the result. Or try to place body weight on one leg and then the other. A difference in your ability to support your weight is another suggestion of an injury that requires attention.

Immediate Injury Treatment: Step-by-Step Guidelines

  • Stop the activity immediately.
  • Wrap the injured part in a compression bandage.
  • Apply ice to the injured part (use a bag of crushed ice or a bag of frozen vegetables).
  • Elevate the injured part to reduce swelling.
  • Consult your health practitioner for a proper diagnosis of any serious injury.
  • Rehabilitate your injury under professional guidance.
  • Seek a second opinion if you are not improving.