Symptoms of OA

The signs and symptoms of osteoarthritis vary by person, but usually include pain, stiffness, and reduced physical function. Osteoarthritis can also be accompanied by bony outgrowths around the joints. Some of the most common things to look for are:

Pain or deep aching in a joint
Joint pain with motion
Pain with use (early in the disease)
Pain at rest (later in the disease)
Crackling or crepitus (grinding, creaking noise or sensation within a joint)
Stiffness: usually lasts less than one hour; may be related to the weather, affects specific involved joints, causing limited joint motion
Instability of weight bearing joints
Joint deformity (usually in the later stages)
Limited joint motion

Since cartilage does not contain pain receptors, the pain in osteoarthritis usually comes from irritation or damage to other tissues within the joint.

Which Joints are Affected?

Osteoarthritis can affect almost any joint in the body. However, it most commonly affects the main weight bearing joints including:

- Knee

- Hip

- Spine

The most common non-weight bearing areas affected are the hand and the jaw. Hand osteoarthritis is more common in women and is frequently seen with bony overgrowth at the joints. Osteoarthritis in the spine primarily affects the neck and the lower back. Frequently, OA of the spine is linked to thinning of the discs that act as cushions between the vertebrae.

If you think you have symptoms of OA it is important to see your doctor. Your doctor will be able to review the signs, symptoms, and order the appropriate diagnostic tests. He or she will be able to determine the best course of action for your care. Your doctor will likely recommend a series of self-care or home-care practices, things you can do to improve your state of health. Insulite Labs is available to offer supportive systems as you deal with your self-care needs on a day-to-day basis.

Stages of OA

Osteoarthritis is usually described in three stages: mild, moderate, and severe.

What Causes Pain in OA?

Since cartilage does not contain pain receptors, where does the pain come from? This is an important question, since the lifestyle changes suggested in this program can even influence joint discomfort without necessarily changing the cartilage itself.

The main tissues that contribute to the pain of OA include:

1) tendons and the bursa (which are tiny sacs that cushion movement of tendons)

2) Subchondral bone. Subchondral bone is the bone that lies beneath the cartilage. Subchondral bone has a rich blood supply and the periosteum that covers the bone is rich in sensory nerves. Changes that occur in subchondral bone that might cause symptoms are increased bone density, cysts within the bone, and increased pressure within the bone.

3) Joint edges or margins. Bony outgrowths at the joint margins are very common in OA. These are called osteophytes and can irritate all the surrounding tissues.

4) Synovium. This is the fluid-filled joint capsule, rich with cells and nerve endings. The synovium also contains cells, including white blood cells, that can secrete inflammatory molecules. Thickening and inflammation within the synovium can lead to pain and discomfort.

5) Nerve (pain) fibers. It now appears that pain signals from an injured joint can set up a loop with the spinal cord. The neurons in the spinal cord (called dorsal horn neurons and astrocytes) seem to produce excessive amounts of an immune protein called IL-1b, which feeds back into the joint, worsening the conditions. This loop seems to perpeutate the pain and even push the arthritis further along.

6) Nerve (pressure) fibers. These nerve sensors are located in the cartilage. They sense changes in mechanical force or pressure. They seem to fire more actively when there is not enough joint lubricant fluid. This is called hyaluronic acid, which is affected by some of our lifestyle habits like moving and exercising.

[INSERT FIGURE-ANATOMY OF THE KNEE JOINT]

Can Pain Cause Osteoarthritis?

Osteoarthritis Cartilage. 2007 Oct;15(10):1134-40. Epub 2007 May 31.

Links

Electromyographic patterns suggest changes in motor unit physiology associated with early osteoarthritis of the knee.

Ling SM, Conwit RA, Talbot L, Shermack M, Wood JE, Dredge EM, Weeks MJ, Abernethy DR, Metter EJ.

Clinical Research Branch, National Institute on Aging Intramural Research Program (NIA-IRP), National Institutes of Health, MD 21225, USA. lingsh@grc.nia.nih.gov

OBJECTIVE: To assess characteristics of active motor units (MUs) during volitional vastus medialis (VM) activation in adults with symptomatic knee osteoarthritis (OA) across the spectrum of radiographic severity and age-comparable healthy control volunteers. METHODS: We evaluated 39 participants (age 65+/-3 years) in whom weight-bearing knee X-rays were assigned a Kellgren & Lawrence (KL) grade (18 with KL grade=0; four each with KL grades=1, 2 and 4; nine with grade 3). Electromyography (EMG) signals were simultaneously acquired using surface [surface EMG (S-EMG)] and intramuscular needle electrodes, and analyzed by decomposition-enhanced spike-triggered averaging to obtain estimates of size [surface-represented MU action potentials (S-MUAP) area], number [MU recruitment index (MURI)] and firing rates [MU firing rates (mFR)] of active MUs at 10%, 20%, 30% and 50% effort relative to maximum voluntary force [maximal voluntary isometric contraction (MVIC)] during isometric knee extension. RESULTS: Knee extensor MVIC was lower in OA participants, especially at higher KL grades (P=0.05). Taking the observed force differences into account, OA was also associated with activation of larger MUs (S-MUAP area/MVICx%effort; P<0.0001). In contrast, the estimated number of active units (MURI/MVICx%effort) changed differently as effort increased from 10% to 50% and was higher with advanced OA (KL=3, 4) than controls (P=0.0002). CONCLUSION: VM activation changes at the level of the MU with symptomatic knee OA, and this change is influenced by radiographic severity. Poor muscle quality may explain the pattern observed with higher KL grades, but alternative factors (e.g., nerve or joint injury, physical inactivity or muscle composition changes) should be examined in early OA.

Comparing Osteoarthritis with Rheumatoid Arthritis

Since osteoarthritis and rheumatoid arthritis are the most commonly diagnosed forms of arthritis, it is helpful to have a brief comparison. (need to redo and reference: http://health.yahoo.com/arthritis-resources/characteristics-of-rheumatoid-arthritis-and-osteoarthritis/healthwise--aa19377.html


Characteristic	Rheumatoid arthritis (1.3 million U.S.)	Osteoarthritis (27 million U.S.)
Age at which the condition starts	It may begin any time in life.	It usually begins later in life.
Speed of onset	Relatively rapid, over weeks to months	Slow, over years
Joint symptoms	Joints are painful, swollen, and stiff.	Joints ache and may be tender but have little or no swelling.
Pattern of joints that are affected	It often affects small and large joints on both sides of the body (symmetrical), such as both hands, both wrists or elbows, or the balls of both feet.	Symptoms often begin on one side of the body and may spread to the other side. Symptoms begin gradually and are often limited to one set of joints, usually the finger joints closest to the fingernails or the thumbs, large weight-bearing joints (hips, knees), or the spine.
Duration of morning stiffness	Morning stiffness lasts longer than 1 hour.	Morning stiffness lasts less than 1 hour; returns at the end of the day or after periods of activity.
Presence of symptoms affecting the whole body (systemic)	Frequent fatigue and a general feeling of being ill are present.	Whole-body symptoms are not present, though fatigue is often overlooked in OA