Osteoarthritis Overview

An estimated 21 million people in the United States have some type of osteoarthritis (OA),¹ a common form of arthritis that affects the joints including knees, hips, feet, and back. The primary symptoms include joint pain, swelling, and tenderness around the joint, as well as stiffness with limited joint motion.

What is OA of the knee?

OA of the knee occurs when the cartilage at the ends of the bones in a joint breaks down and the bones begin to rub together. This rubbing eventually causes the synovial fluid (the thick liquid surrounding the knee joint) to break down and lose its ability to cushion and lubricate the joint.

The most common causes of OA of the knee include:

Advancing age
Excessive weight; obesity
Repeated overuse via occupational, athletic, and/or recreational activities
Previous joint trauma or injury
Genetic factors such as a family history of OA
Other diseases or forms of arthritis
Gender—OA affects females (65%) more than males (35%)²

It is important to note that OA of the knee can also occur without any of these factors. As the population ages, the number of patients with OA of the knee will continue to grow.

How is OA of the knee diagnosed?

Only a doctor can diagnose and treat OA of the knee. During an office visit, the doctor will get a patient’s complete medical history as well as a timeline of the pain’s onset and symptom progression. Standard pain-measurement questionnaires will also help the doctor understand the severity of the pain and its impact on day-to-day functioning. Finally, the doctor will most likely recommend an X-ray, MRI, or CT scan to determine the cause of the discomfort.

How is it treated?

There is no cure for OA of the knee, but there are several treatment protocols to help alleviate and manage the pain:

Nonpharmacologic: Lifestyle changes such as weight loss and exercise
Analgesics: Pain relievers, including over-the-counter acetaminophen (Tylenol^{^®}) and prescription drugs
Nonsteroidal anti-inflammatory drugs (NSAIDs): Pain relievers that also treat inflammation, both over-the-counter (Advil^®, Aleve^®) and prescription drugs
COX-2 inhibitors: An alternative to long-term NSAID use that has less risk of stomach damage from prolonged use
Steroid injections
Viscosupplementation or HA therapy: A series of 3 to 5 weekly injections of hyaluronic acid (HA) into the knee
Total knee replacement surgery

What is viscosupplementation or HA therapy?

HA is the naturally occurring liquid found in joint cartilage and synovial fluid that cushions the joint during movement and while carrying body weight.

Healthy synovial fluid contains a high concentration of naturally occurring HA that helps lubricate and protect the joint and cartilage. In a knee with OA, the synovial fluid loses its viscosity and elasticity, making both slow and fast movements painful, while the associated breakdown of HA leads to pain and inflammation. HA therapy works to help restore the synovial fluid in the knee joint, providing the ability to cushion, lubricate, and protect the knee joint while reducing pain and increasing joint motion.

HA therapy is a proven treatment option that has been available in the United States since 1998. There are currently 5 HA therapies on the market, 4 of which are derived from avian by-products; that is, they are made from the combs of roosters and hens. Only 1 is made through bioengineering*, which leads to the highest degree of purity.

Treatment is administered through a series of 3 to 5 weekly injections given in a doctor’s office, without the need for general anesthesia. While some patients may feel relief after 1 injection, most patients experience relief after 3 injections. HA therapy can provide pain relief for up to 6 months.

*Derived through bacterial fermentation. Webster’s Third New International Dictionary, Unabridged.

Tylenol is a registered trademark of McNeil Consumer & Specialty Pharmaceuticals. Advil is a registered trademark of Wyeth Consumer Healthcare. Aleve is a registered trademark of Bayer HealthCare LLC.

References:
1. Lawrence RC, Helmick CG, Arnett FC, et al. Estimates of the prevalence of arthritis and selected musculoskeletal disorders in the United States. Arthritis Rheum. 1998;41:778-799. 2. Data on file. Ferring Pharmaceuticals Inc.