Osteoarthritis (OA) is by far the most common joint disorder in the United States and throughout the world. It is a leading cause of pain and disability in the elderly, mostly because of its predilection for the weight-bearing joints. And so today I will talk about osteoarthritis in an important weight-bearing joint: the knee.
Overweight people are at greater risk of developing knee OA. In addition, major knee injuries such as ligament or meniscal tears are common causes of knee OA. Ultimately, whether it is the extra force on the knee due to obesity or the disruption of the normal internal components of the knee due to a meniscal or ligament tear, OA is caused by a change in the synthesis and degradation of cartilage and adjacent bone. This in turn results in loss of cartilage and damage to bone, manifested in the patient by pain, swelling, and limited range of motion of the knee.
The American College of Rheumatology (ACR) suggests initially treating knee OA through weight loss, physical therapy and exercising. These initial treatment modalities are obviously safe, but unfortunately often not in and of themselves effective.
The main indication for systemic drug therapy in knee OA is pain relief. Acetaminophen ("Tylenol") is the initial systemic drug recommended by the ACR for the treatment of knee OA. But for many patients acetaminophen may not be as beneficial as nonsteroidal anti-inflammatory drugs (NSAIDs), examples being naproxen and ibuprofen. Tramadol can be used for breakthrough pain. Narcotics have been used for severe pain.
Localized drug therapy can be extremely helpful also. Topical drugs such as NSAID creams or capsaicin can be helpful for some patients with knee pain due to OA. "Steroid" injections into the knee can be very helpful as an addition to oral systemic therapy, or as the main treatment in patients who cannot tolerate NSAIDs or Celebrex. Many experts, however, prefer to limit steroid injections into a knee to perhaps three times each year due to the fear of possible cartilage damage.
Viscosupplementation therapy is the injecting into the knee of hyaluronan or its derivatives. This restores the normal knee fluid's ability to cushion, lubricate and protect the knee joint. Hyaluronan is a component of the normal chemistry of the knee, which is decreased when the knee is stricken by OA. Some studies have shown such therapy to be effective in knee OA for up to one year. There are other studies which suggest that using viscosupplementation in more early knee OA results in less joint deterioration over time. Viscosupplementation, like steroid injections, can be helpful as an addition to oral therapy, or as a substitute for those patients who cannot tolerate the oral pain relievers.
Euflexxa is the newest hyaluronan on the market, and it is the only one not derived from rooster or chicken combs. This is important because there is therefore a lesser chance of an allergic reaction due to the possibility of foreign (bird) protein being injected into the knee. I have seen the reaction when a patient does have a reaction to other hyaluronans I have injected into the knee; there can be swelling, pain and inflammation. It is nice to have Euflexxa available.