What is Osteoarthritis
Osteoarthritis is caused by the breakdown and loss of cartilage in one or more joints. Cartilage protects and cushions the bones during movement. When cartilage begins to break down or is destroyed, symptoms begin to develop that can inhibit one's ability to perform normal activities. 

Signs and Symptoms ​

• Pain and stiffness in the joint
• Swelling in or near the joint
• Difficulty walking or bending the joint

In some cases, patients with osteoarthritis may develop a bone spur at the site of the affected joint. Pressure from shoes can cause pain where the spur is located, and sometimes can cause blisters or calluses over its surface. 

Causes
Osteoarthritis's largest cause is age; as we get older, the cartilage wears down from years of use and repeated stress. Injuries, too, can cause osteoarthritis, though it can take months or even years for the condition to set in. Finally, osteoarthritis can develop as a result of abnormal foot structure, such as flat feet or a high arch.

Diagnosis
To diagnose this condition, your podiatrist will perform a thorough examination of the foot in question, looking for swelling of the joint, limited mobility, and pain associated with movement. If you have a noticable bone spur, it will also be evaluated.