The following laboratory tests may be helpful in determining causes of restless legs syndrome (RLS) or identifying conditions that rule it out. 1  Blood glucose tests for diabetes. 2  Tests for kidney problems. 3  In certain cases, tests for thyroid hormone, magnesium, and folate levels.
Osteoarthritis. Osteoarthritis is the most common form of arthritis in the knee. It is a degenerative,wear-and-tear type of arthritis that occurs most often in people 50 years of age and older, but may occur in younger people, too. In osteoarthritis, the cartilage in the knee joint gradually wears away.he most common types of arthritis are osteoarthritis and rheumatoid arthritis, but there are more than 100 different forms. In 2012, more than 51 million people reported that they had been diagnosed with some form of arthritis, according to the National Health Interview Survey.
Osteoarthritis can be limited to one joint or start in one joint usually the knee, hip, hand, foot or spine or it can involve a number of joints. If the hand is affected, usually many joints of the fingers become arthritic. Osteoarthritis probably does not have a single cause, and, for most people, no cause can be identified. Age is a leading risk factor, because osteoarthritis usually occurs as people get older. However, research suggests that joints do not always deteriorate as people age. Other factors seem to contribute to osteoarthritis.