Knee Osteoarthritis

Knee Osteoarthritis

Knee Osteoarthritis

Arthritis is inflammation of one or more of your joints. Pain, swelling, and stiffness are the primary symptoms of arthritis. Any joint in the body may be affected by the disease, but it is particularly common in the knee.

 

Knee arthritis can make it hard to do many everyday activities, such as walking or climbing stairs. It is a major cause of lost work time and a serious disability for many people.

Anatomy of the knee

The knee is the largest joint in the body and having healthy knees is required to perform most everyday activities.

 

The knee is made up of the lower end of the thighbone (femur), the upper end of the shinbone (tibia), and the kneecap (patella). The ends of these three bones where they touch are covered with articular cartilage, a smooth substance that protects the bones and enables them to move easily.

 

The menisci are located between the femur and tibia. These C-shaped wedges act as “shock absorbers” that cushion the joint.

 

Large ligaments hold the femur and tibia together and provide stability. The long thigh muscles give the knee strength.

 

All remaining surfaces of the knee are covered by a thin lining called the synovial membrane. This membrane releases a fluid that lubricates the cartilage, reducing friction to nearly zero in a healthy knee.

 

Normally, all of these components work in harmony. But disease or injury can disrupt this harmony, resulting in pain, muscle weakness, and reduced function.

Normal knee anatomy. In a healthy knee, these structures work together to ensure smooth, natural function and movement.

Cause

The most common cause of chronic knee pain and disability is arthritis. Although there are many types of arthritis, most knee pain is caused by just three types: osteoarthritis, rheumatoid arthritis, and post-traumatic arthritis.

 

  • Osteoarthritis: This is an age-related “wear and tear” type of arthritis. It usually occurs in people 50 years of age and older, but may occur in younger people, too. The cartilage that cushions the bones of the knee softens and wears away. The bones then rub against one another, causing knee pain and stiffness.
  • Rheumatoid arthritis: This is a disease in which the synovial membrane that surrounds the joint becomes inflamed and thickened. This chronic inflammation can damage the cartilage and eventually cause cartilage loss, pain, and stiffness. Rheumatoid arthritis is the most common form of a group of disorders termed “inflammatory arthritis.”
  • Post-traumatic arthritis: This can follow a serious knee injury. Fractures of the bones surrounding the knee or tears of the knee ligaments may damage the articular cartilage over time, causing knee pain and limiting knee function.

Nonsurgical Treatment

As with other arthritic conditions, initial treatment of arthritis of the knee is nonsurgical. Your doctor may recommend a range of treatment options.

 

Lifestyle modifications. Some changes in your daily life can protect your knee joint and slow the progress of arthritis.

  • Minimize activities that aggravate the condition, such as climbing stairs.
  • Switching from high impact activities (like jogging or tennis) to lower impact activities (like swimming or cycling) will put less stress on your knee.
  • Losing weight can reduce stress on the knee joint, resulting in less pain and increased function.

 

Physical therapy: Specific exercises can help increase range of motion and flexibility, as well as help strengthen the muscles in your leg.

 

Assistive devices: Using devices such as a cane, wearing shock-absorbing shoes or inserts, or wearing a brace or knee sleeve can be helpful.

 

Other remedies: Applying heat or ice, using pain-relieving ointments or creams, or wearing elastic bandages to provide support to the knee may provide some relief from pain.

 

Medications:

  • Over-the-counter, non-narcotic pain relievers and anti-inflammatory medications are usually the first choice of therapy for arthritis of the knee.
  • Another type of pain reliever is a nonsteroidal anti-inflammatory drug, or NSAID (pronounced “en-said”). NSAIDs, such as ibuprofen and naproxen, are available both over-the-counter and by prescription.
  • Corticosteroids (also known as cortisone) are powerful anti-inflammatory agents that can be injected into the joint These injections provide pain relief and reduce inflammation; however, the effects do not last indefinitely.
  • Viscosupplementation involves injecting substances into the joint to improve the quality of the joint fluid.
  • Glucosamine and chondroitin sulfate, substances found naturally in joint cartilage, can be taken as dietary supplements. Although patient reports indicate that these supplements may relieve pain, there is no evidence to support the use of glucosamine and chondroitin sulfate to decrease or reverse the progression of arthritis. 

Osteoarthritis often results in bone rubbing on bone. Bone spurs are a common feature of this form of arthritis.

(Left) Severe osteoarthritis. (Right) The arthritic cartilage and underlying bone has been removed and resurfaced with metal implants on the femur and tibia. A plastic spacer has been placed in between the implants. The patellar component is not shown for clarity.

Surgical Treatment