Reasons for Primary Total Knee Replacement

The primary indication for knee replacement surgery is pain of the knee joint. A painful and dysfunctional knee can severely affect your ability to lead a full and active life. Advancements in artificial knee surgery over the last 25 years have made this surgery a common and very viable solution for knee pathology.

Arthritic kneeArthritis is the number one reason why people have total knee replacements. Many patients elect to have the surgery because the pain associated with arthritis becomes too unbearable or prevents them from leading a normal and active life. The most common types of arthritis include:

  • Osteoarthritis (degenerative arthritis, wear and tear arthritis)
  • Post-traumatic arthritis caused by fractures, ligament injuries and/or meniscus tears
  • Rheumatoid arthritis

Symptoms of Knee Arthritis Include:

  • Pain – This can be present during activity or simply at rest
  • Swelling – Also known as “water in the knee,” causes increased pain with knee flexion
  • Grating and crepitus – This is caused by the irregular diseased surfaces of the joint grinding against each other
  • Stiffness and decreased range of motion
  • Limping
  • Deformities -This can come in the form of bowed legs or knocked knees. Typically, this occurs because the cartilage and bone are worn down on one side of the knee or the other


There are many conditions that can result in degeneration of the knee joint. Osteoarthritis is the most common reason that patients undergo knee replacement surgery. This condition is commonly referred to as “wear and tear” arthritis. Also, another common medical name for this problem is degenerative joint disease. The cartilage of the joint simply degenerates, breaks down and sloughs off the underlying bone. Osteoarthritis occurs with no previous history of injury to the knee joint – the knee simply “wears out.”

X-ray of a healthy knee X-ray of an arthritic knee
X-ray of a healthy knee X-ray of an arthritic knee

Post-traumatic arthritis:

Post-traumatic arthritis is very similar to osteoarthritis in symptoms and how it looks on x-ray and under the microscope. The only difference is that this disease is caused by trauma or injury. The trauma can come in the form of a fracture of the knee, torn cartilage or torn ligaments. The trauma alters the mechanics of the knee and over time the joint begins to break down.

Rheumatoid arthritis:

Rheumatoid arthritis is an autoimmune disorder. That is, the patients own body attacks the cartilage. The body mounts an aggressive inflammatory response against the cartilage. This causes joint destruction, pain and swelling.


Osteonecrosis is an uncommon entity that causes knee pain. There are many reasons osteonecrosis occurs. One reason is long term steroid use. Osteonecrosis is where bone has lost its blood supply either temporarily or permanently. This within itself can cause severe pain. As the body tries to heal itself, the affected bone can become weak and break down. If the osteonecrosis is near the surface of the knee joint, the mechanics of the joint may be altered and the joint will break down.

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