Osteoarthritis is a degenerative condition affecting the joints resulting in loss of cartilage within the joint, formation of bony spurs at the edge of the joint, called osteophytes, and thickening of the joint capsule (synovium) with swelling.  This results in pain, swelling, stiffness, crepitus (a grating or grinding sensation) and loss of function. 

Risk factors associated with developing the condition include increasing age (>40), gender (more common in women), obesity, previous joint injury and disease and genetic factors.

Osteoarthritis can affect any joint, however it commonly affects the neck, back, hips, knees, hands, and feet.