What happens in osteoarthritis?

Osteoarthritis is most common in joints required to bear weight over the years, such as the knees, hips, feet and spine and often comes on gradually over months or years.  Except for the intense pain in the affected joint; you usually do not feel sick, and there is no unusual fatigue or tiredness as with other types of arthritis.

As age increases over age 50 or after injuries to joints, there may be minor damage to the cartilage which is not able to be completely repaired. The injury can be major and obvious, like a knee injury in sports when cartilage is damaged.  Or, the injury might accumulate from minor injuries over years.  These accumulated injuries may build up to damage the cartilage, leading to osteoarthritis. 

Gradually, as more and more damage happens,  the cartilage begins to wear away or it doesn’t work as well to cushion the joint.  For example, the extra stress on knees from being overweight can cause more damage to knee cartilage.  This allows the cartilage to wear out faster than normal. 

Interestingly, the hands also seem to be at higher risk for osteoarthritis when a person is overweight. Researchers now speculate that there are probably other unknown reasons than extra weight for a higher risk of osteoarthritis.

As the cartilage becomes worn, the smoothness of cartilage cushioning the joint is lost.  This can cause pain when the joint is moved. Along with the pain, sometimes you may hear a grating sound when the roughened cartilage on the surface of the bones rubs together. Bumps may appear, especially on the fingers and feet.

      

With osteoarthritis, the cartilage that supports and cushions the joints of the hands, spine, hips, and knees wears away and causes the bones to rub against each other. This leads to debilitating pain, inflammation, swelling, stiffness and reduced mobility. The rubbing of the bones may cause bone spurs and deformities of the joint. The pain of osteoarthritis often makes it difficult to perform everyday tasks such as taking a bath. Kneeling, bending, sitting or standing may also become difficult. A doctor can recommend treatments to reduce the symptoms of osteoarthritis. 

In osteoarthritis, the cartilage that caps and protects the bones within a joint wears down. This exposes bone to bone, which is painful and also irritating to the soft tissues. Bone spurs (little stubs of new bone growth) form in response to this irritation, so that the joint gradually enlarges with bony growths. A low-grade inflammation develops in the surrounding soft tissues.