Symptoms wax and wane from day to day. This is not entirely true. Long distance runners do not have a higher rate of OA than nonrunners. History of trauma is a common cause of OA but by far and away, the most common cause is genetics. Labs do not help in the diagnosis.
Most useful test is the radiograph.
Bony sclerosis, loss of cartilage, and bone spurs with bone space narrowing are noted. Interestingly, ankles are rarely involved. Women 2-3 times more affected. Pathogenesis involves synovial thickening and eventually death and destruction of cartilage. Chronic inflammatory disease, which is autoimmune.