Frequently Asked Questions

Questions and Answers About Osteoarthritis

What is osteoarthritis?

Osteoarthritis (OA), a form of arthritis, is a degenerative joint disease characterized by the breakdown and eventual loss of joint cartilage. Cartilage is a protein substance that serves as a cushion between the bones of a joint. With OA, the top layer of cartilage breaks down and wears away, allowing bones under the cartilage to rub together.

What causes OA of the knee?

Although the root cause of OA is unknown, the risk of developing symptomatic OA is influenced by multiple factors, such as age, gender, and inherited traits that can affect the shape and stability of the
joints. Other factors can include the following:

  • A previous knee injury;
  • Repetitive strain on the knee;
  • Improper joint alignment;
  • Being overweight; and
  • Exercise or sports-generated stress placed on the knee joints.

What are the symptoms of OA of the knee?

Symptoms of OA of the knee include the following:

  • Pain while standing or walking short distances, climbing up or down stairs, or getting in and out of chairs;
  • Knee pain with activity;
  • Start-up pain or stiffness when activities are initiated from a sitting position;
  • Stiffness in the knee joint after getting out of bed;
  • Swelling in one or more areas of the knee; and
  • A grating sensation or crunching feeling when using the knee.

How is OA of the knee diagnosed?

Your physician will begin by reviewing your medical history and discussing your symptoms with you. He or she will observe the natural movement of your knee, evaluate your knee and ankle joint alignment, and check your reflexes, muscle strength, range of motion, and ligament stability in the affected knee. Your physician may order X-rays to determine how much joint or bone damage has been done, how much cartilage has been lost, and whether bone spurs are present. Additional medical imaging tests, such as computed tomography or magnetic resonance imaging, may be ordered to determine the exact site and the extent of the damage. Your physician may also order blood tests to rule out other causes of symptoms or may order a joint aspiration, which involves drawing fluid from the joint through a needle and examining the fluid under a microscope.

How is OA treated?

Whether your OA is mild or severe, your physician will likely recommend certain lifestyle changes to reduce stress on your knee joints. Additional disease and pain-management strategies may include physical therapy, steroid injections, and over-the-counter pain medications, such as cetaminophen, nonsteroidal anti-inflammatory drugs, or topical pain relieving creams.

You should speak with your physician if your symptoms are not responding to non-surgical solutions or if your pain can no longer be controlled by medication. You could be a candidate for surgery.

The most common surgical knee intervention performed for OA is a total knee replacement. During this procedure, the natural joint is removed and replaced with an artificial implant. This treatment option is usually offered to patients with advanced osteoarthritis of the knee.

Total knee replacement is not always optimal for patients with early- or mid-stage osteoarthritis in just one or two compartments of the knee. For atients with partial OA of the knee, MAKOplasty® Partial Knee Resurfacing may be the more appropriate solution.