Osteoarthritis is the most common joint disease and the largest cause of disability in the United States. Nearly 50% of men and women over the age of 65 years report being diagnosed with osteoarthritis. Of that number, knee osteoarthritis is the most common, affecting 10% of men and 13% of women older than 60 years.* The most common symptoms of knee osteoarthritis are joint pain and stiffness, especially first thing in the morning or after long periods of rest. Osteoarthritis arises from the breakdown of cartilage in joints as well as degeneration of the subchondral bone (the bone just underneath the cartilage) and the synovium (soft tissue that lines the joint capsule).
Diagnosing Knee Osteoarthritis
While joint cartilage itself does not show up on x-rays, loss of cartilage in joints can be revealed by apparent loss of joint space between bones. Another common sign of osteoarthritis seen on x-rays is the growth of osteophytes, which are small bone spurs that develop in areas that have undergone cartilage loss.
Treating Knee Osteoarthritis
At this time, there is no known treatment to reverse osteoarthritis. Current treatments for osteoarthritis aim to slow the progression of the disease and delay the need for joint replacement surgery, which some patients may eventually need. Non-invasive treatments for osteoarthritis include NSAIDs and physical therapy. Stretching and strengthening programs performed with a physical therapist may improve biomechanics and thereby relieve pain and reduce further joint degeneration. Invasive treatment options for osteoarthritis commonly include cortisone and hyaluronic acid injections. Cortisone injections act by reducing the inflammation caused by osteoarthritis. Hyaluronic acid injections work by simultaneously replacing and promoting the production of endogenous (naturally occurring) hyaluronic acid that exists in healthy knees. When conservative measures like those described above no longer provide relief, patients and their doctors may begin to discuss joint replacement surgery.
*Zhang, Y., & Jordan, J. M. (2010). Epidemiology of Osteoarthritis. Clinics in Geriatric Medicine, 26(3), 355–369. http://doi.org/10.1016/j.cger.2010.03.001