Arthritis Treatment: Knee Osteoarthritis And The Epidemic Of Knee Replacements - Part 1

The most common form of arthritis, osteoarthritis (OA), affects more than 20 million Americans. One of the primary targets for this disease is the knee.

OA affects articular cartilage, the gristle that caps the ends of long bones. Articular cartilage is a "pudding" that is made up of a matrix of proteoglycans (arrangements of proteins and glycogen molecules.) In addition, there is a framework of tough collagen fibers. Within this proteoglycan/collagen structure are cells called chondrocytes.

The maintenance of normal cartilage integrity is highly dependent on the metabolic function of these chondrocytes.

Osteoarthritis is a wear and tear disease of articular cartilage. It arises as a result of the lack of ability of cartilage to keep up with excessive breakdown.

The first step that occurs in the process of OA is an alteration in the matrix. This causes loss of cartilage resiliency. In addition, proteins that promote inflammation (called inflammatory cytokines) are produced by the joint lining. These cytokines activate destructive enzymes, called proteases which degrade the matrix and cause the chondrocytes to malfunction.

So far, the treatment of osteoarthritis is mostly symptomatic. Various medicines, called non-steroidal anti-inflammatory drugs (NSAIDS), analgesics (pain-killers), exercises, physical therapy, and injections are used to provide palliative relief. Ultimately, though, patients will go on to have knee replacement surgery.

While this operation has generally been reserved for elderly patients, joint replacement surgery is increasing at an alarming rate among Baby Boomers who want to maintain a certain level of activity.

According to a recent report (Associated Press, Lindsay Tanner), "nearly one in twenty Americans older than 50 has an artificial knee- that's four million people!"

The federal Agency for Healthcare Research and Quality has issued a recent report showing that knee replacements tripled in people ages 45 to 64 between 1997 and 2009. While it's admirable and speaks to the increased activity level in a group of patients that formerly would be sitting in rocking chairs, in another sense, it raises other issues.

This is particularly disturbing because revision surgery (replacement of the replacement) will be needed in the future and this is a much more difficult and costly endeavor. Revision surgery takes longer, requires more expertise, is more complicated, and has a greater likelihood of complications.

Obviously, there is a public health problem if people with knee OA are going on to get an operation that will add tremendous costs to an already overburdened healthcare system. More in a future article.