Osteoarthritis of the Knee

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Arthritis is an inflammation of the joint and is a broad term that is used to describe over 100 diseases. It is characterized by pain and stiffness in the affected joint. The three most common types of arthritis are:


  • The most common type
  • Also called “degenerative joint disease” or “wear-and-tear arthritis”
  • Characterized by disintegration of joint cartilage

Rheumatoid Arthritis

  • An autoimmune disease
  • Inflammation can lead to severe joint damage
  • Symptoms typically more severe than in osteoarthritis

Psoriatic Arthritis

  • Joint swelling caused by the skin disease psoriasis


Osteoarthritis is the degeneration of cartilage within a joint. When joints move, the surfaces glide and roll upon each other. Cartilage softens the ends of the bone and reduces the friction when the bone ends move against each other. When one suffers from osteoarthritis, the cartilage has degenerated, increasing the friction between bone-on-bone contact in the affected joint. The individual suffers from pain, a stiff joint, and decreased range of motion (ROM). Osteoarthritis typically affects individuals in their 60s and 70s when normal wear-and-tear of the joints throughout life has disintegrated the cartilage. Osteoarthritis can also affect younger individuals following post-traumatic events, inflammatory diseases, and infections that cause damage to the joint cartilage.

Osteoarthritis typically affects joints that bear weight: the knees, hips, ankles, and spine. Symptoms progress gradually, over many months and even years. The pain and swelling of osteoarthritis may make it difficult to perform many routine tasks.

Osteoarthritis is quite common, especially as an individual ages. As many as 30% of individuals in the United States suffer from some form of osteoarthritis between the ages of 45 and 64. This percentage climbs as high as 63-85% in individuals over the age of 64.

Mono-Compartment Osteoarthritis of the Knee

The knee joint is the articulation, or joining, of the femur and the tibia. Articular cartilage covers the end of each bone, protecting the ends of the bones from each other and aiding in smooth motion through the joint. When osteoarthritis occurs, the articular cartilage breaks down.

In normal anatomy the knee is composed of three compartments:

  • Medial Compartment
  • Lateral Compartment
  • Patellofemoral Compartment

When the osteoarthritis affects a single compartment of the knee, it is referred to as mono-compartment osteoarthritis. The most common compartment affected is the medial compartment; it is referred to as Medial Compartment Osteoarthritis (MCOA). Osteoarthritis affecting the lateral compartment is referred to as Lateral Compartment Osteoarthritis (LCOA). Osteoarthritis may also affect the Patellofemoral Compartment

In osteoarthritis of the knee, degeneration of the articular cartilage results in deterioration of the joint surfaces. This results in deformities of both the bones (femur and tibia) and the joint soft tissues, leading to pain, joint stiffness, decreased ROM, gait abnormalities, and malalignment.

At the Paley Institute we treat Mono-Compartment Osteoarthritis of the Knee with specialized osteotomies (bone cuts) of the knee. The goal of treatment is to restore the functionality of the joint and delay the need for joint replacement surgeries (i.e. total knee replacement). We have achieved excellent results with joint preservation using specialized osteotomies that Dr. Paley developed.

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