Our knowledge of orthopaedics. Your best health.

A joint is where the ends of two or more bones meet. For example:

• The hip joint is where the top of the thighbone (femoral head) meets a hollowed-out portion of the pelvis (acetabulum).
• The knee joint is formed between the thighbone (femur) and the bones of the lower leg (tibia and fibula). 

A healthy hip joint.

A healthy joint glides easily without pain because a smooth, elastic tissue called articular cartilage covers the ends of the bones that make up the joint.

With osteoarthritis, the articular cartilage that covers the ends of bones in the joints gradually wears away. Where there was once smooth articular cartilage that allowed the bones to glide easily against each other when the joint bent and straightened, there is now a frayed, rough surface. Joint motion along this exposed surface is painful.

Osteoarthritis often results in bone rubbing on bone. This illustration shows a healthy knee and a knee with osteoarthritis. Bone spurs are a common feature of this form of arthritis.

Osteoarthritis usually develops after many years of use. It affects people who are middle-aged or older. Other risk factors for osteoarthritis include obesity, previous injury to the affected joint, and family history of osteoarthritis.

Osteoarthritis can affect any joint in the body including the joints of the spine. Symptoms may range from mild to disabling.

Without cartilage, bones rub directly against each other as the joint moves. A joint affected by osteoarthritis may be stiff, painful, and inflamed,

• Pain or a dull ache will develop gradually over time.
• Pain may be worse in the morning and feel better with activity.
• Vigorous activity may cause pain to flare up.
• The joint may stiffen and look swollen, enlarged, or "out of joint."
• A bump may develop over the joint.

Hands of a patient with osteoarthritis. Bone growths on the little finger are typical of osteoarthritis.

Joint movements such as bending, straightening, and rotating may become more difficult and loss of motion may follow.

Loose fragments of cartilage can interfere with the smooth motion of a joint. The joint may lock or stick. It may creak, click, snap, or make a grinding noise (crepitus). An arthritic joint may weaken and weight bearing joints such as a knee or ankle may buckle and give way.

Although osteoarthritis cannot be cured, early diagnosis and treatment can help maintain joint mobility, relieve pain and improve function.

When you visit your doctor, they will: 

• Do a complete medical history
• Perform a physical examination
• Order X-rays and possibly laboratory tests 

Medical History

Your doctor will want to know:

• Whether the joint has ever been injured
• When the joint pain began
• The nature of the pain
  • Is it continuous, or does it come and go?
  • Does it occur in other parts of the body?
  • Does it cause nighttime symptoms?
  • Does it occur only with activity or at rest as well?
• Whether there any things that make the pain better

Physical Examination

Your doctor will then examine the affected joint in various positions to see if there is pain or restricted motion. They will look for:

• Creaking or grinding noises (crepitus) that indicate bone-on-bone friction
• Muscle loss (atrophy)
• Signs that other joints are involved
• Signs of injury to muscles, tendons, and ligaments

X-rays

X-rays are taken in different positions to show the extent of joint deterioration, including:

• Narrowing of joint space
• Thinning or erosion of bone
• Bone spurs or other abnormalities

X-rays can also help your doctor distinguish between various forms of arthritis.

Laboratory Tests

Sometimes laboratory tests, such as blood tests, can help rule out other diseases that cause symptoms similar to osteoarthritis.