First, let's set the record straight: osteoarthritis (OA) is a disease. OA is not a normal part of aging, although it is understandable why people may think of it that way. OA usually strikes after age 45, and becomes increasingly common with age. But this disease clearly is more than just "wear and tear over time." And it's not a problem only for old people. In fact, for the some, the early stages of disease may start in youth or young adulthood.
OA is a type of arthritis, or joint disease. Specifically, it is a disease of cartilage and bone of a joint. In a healthy joint, cartilage is slippery and cushiony. It allows the bones of a joint to glide against each other with ease, and it helps absorb the force of weight on a joint during movement.
Osteoarthritis destroys cartilage and damages joints
In the early stage of OA, healthy cartilage begins to break down and wear away. Over time, cartilage thins and may erode to the point that two bones rub against each other. Eventually, OA may causes changes in the shape of the bone, affecting the structure and function of the joint. In severe OA, joint damage and pain may significantly impact daily activities, leading to loss of joy in life, the ability to work and be independent.
The process of joint damage in OA is complex and not fully understood. The specific events that start the breakdown of cartilage and the factors that contribute to the progression of OA are the focus of intense research. Learn more about the cause of OA here.
Symptoms of osteoarthritis
The symptoms of OA generally creep in, rather than show up suddenly. Symptoms can vary depending on which joints are involved as well as a person's age, body weight, joint alignment, and fitness and physical activity level. Not everyone is affected by OA in the same way, but common symptoms and signs include:
- Persistent or recurrent pain, aching, or tenderness in or around a joint
- Stiffness or limited range of motion in a joint
- Mild swelling around a joint
- Clicking or crackling sound or sensation in a joint when it bends
- Enlargement or changes in the shape of a joint
Pain varies from person to person and from time to time in the same person. Pain often is increased with physical activity and relieved by brief periods of rest; in advanced OA, the pain may occur even at rest or at night.
Joint stiffness typically occurs first thing in the morning but goes away within 30 minutes. Joints also may stiffen up after periods of inactivity (called "gelling"). Significant joint redness, warmth, or swelling are not typical features of OA and should be brought to the attention of a doctor.
Joints affected by osteoarthritis
OA can affect any joint but most often involves the knees, hips, and hands. Joints in the neck, lower back, and feet also may be targeted by OA. Learn more below.
Did You Know?
Facts About Joints Commonly Affected by Osteoarthritis (OA)
| Joint |
Facts |
| Knees |
Knee OA is a leading cause of disability among adults, and is very common—1 in 2 adults (or 2 in 3 obese adults) will develop symptoms of knee OA at some point in their lives. |
| Symptoms (pain, stiffness, limited range of motion) may make it difficult to walk, climb stairs, kneel, and get up from a chair. |
| Advanced disease may cause the knees to bend outward (bow-legged) or inward (knock-kneed). |
| Hips |
Hip OA also is an important and common cause of disability among adults. An estimated 1 in 4 adults will develop symptoms of hip OA by age 85. |
| Symptoms (pain, stiffness, limited range of motion) may limit walking, bending, and normal daily activities. |
| Pain may be felt in the groin, thighs, buttocks, or knees. |
| Hands |
An estimated 1 in 12 people age 60 or older have hand OA. |
| OA of the hands usually involves the joints the fingers or at the base of the thumb. |
| Symptoms include pain, aching, stiffness, limited motion, and numbness. Bony knobs may form in joints closest to the nails (Heberden's nodes) or in the middle joints of the fingers (Bouchard's nodes). |
| Fingers may enlarge or change shape, making it difficult to grasp objects or make a fist. |
OA may involve one or many joints. Common patterns of joint involvement are:
- One joint (for example, a 35-year-old man who develops OA in a knee that was injured when he played college football)
- A few joints (for example, a 54-year-old obese woman who develops OA in both knees and one hip)
- Many joints (for example, a 68-year-old woman with OA in several joints of her hands as well as both hips)
Next: What Causes Osteoarthritis?
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