Why does my knee hurt?

Joints are the locations in your body where two bones meet. Cartilage is located at end of each bone and is a smooth, slippery tissue that allows joints to slide against one another with minimal friction. Once cartilage is damaged, it cannot heal itself. Because pain sensors are located in bones rather than in the cartilage, it is the exposed bone that results in a knee pain.

knee painknee injuries


What causes cartilage damage?

A variety of events can damage cartilage, including:

  • trauma (injury)
  • infection
  • inflammation
  • Arthritis
  • joint that is not properly alignment

A traumatic injury can cause an isolated defect, while malalignment tends to cause widespread damage to both sides of the joint. This is very similar to the way a car tire loses its tread when the wheels are not properly aligned.

Arthritis is the most common of these events and most often occurs where the joints in your knee meet or in the area behind the kneecap. Two of the most common types of arthritis are Osteoarthritis and Rheumatoid Arthritis.

Osteoarthritis (OA)

  • The most common cause of knee pain is osteoarthritis (OA), a degenerative joint disease that causes the cartilage in your joints to break down. When that layer of cartilage is damaged or worn away, your bones grind against one another, and that grinding hurts. You can feel it climbing stairs, working in the garden, or simply when you bend to sit down. It may even keep you up at night.
  • OA can damage the entire knee or be limited to just one side of the knee. If you experience pain only on one side, or compartment, of your knee, your doctor may diagnose you with unicompartmental OA.
  • If you experience knee pain under the knee cap, your doctor may diagnose you with patello-femoral OA. This is not uncommon, as studies have shown that about one out of every 10 patients over the age of 40 have patello-femoral disease.
  • The factors leading to the development and progression of OA include aging, obesity, joint injuries, and a family history of arthritis (genetics). Although there is no cure, early diagnosis and treatment are crucial in slowing or preventing more damage to your joints. Follow our Blog for more ways to alleviate your arthritis pain.knee joint

Rheumatoid Arthritis (RA)

  • In rheumatoid arthritis, the synovium (lining of the joint) becomes inflamed. This inflammation causes chemicals to be released that thicken the synovium and damage the cartilage and bone of the affected joint. This inflammation of the synovium causes knee pain and swelling.
  • The good news about rheumatoid arthritis in the knee is that there are treatments. Rheumatoid arthritis is a disease that typically worsens over the years, so it is common for treatment to involve more than one approach and to change over time. For some people, nonsurgical treatments such as lifestyle changes, medications, and walking aids help alleviate the pain. For others, replacing lost cartilage with tissue grafts may help restore normal function. And for many, knee replacement surgery may be the only long-term solution. Together, you and your doctor can determine the best treatment options for you.

knee replacement


Quick Facts

    • Overweight and obese patients have a higher probability of knee pain due to the increased pressure on the knee joint
    • Nearly 1 in 2 people may develop symptomatic knee OA by the age of 85
    • 2.5 million adults in the United States reported being told by a doctor that they have some form of arthritis
    • HemiCAP® Implants allow patients to Stay Active
    • The ACL, MCL & PCL remain intact with Arthrosurface® Knee HemiCAP® procedures