Osteoarthritis (OA) is the most common type of arthritis. It is caused by breakdown of the cartilage that protects the ends of bones where they form a joint. This leads to pain and inflammation.
Rheumatoid arthritis (RA) is another common type of arthritis. It is an autoimmune disorder. The immune system attacks the joints, causing inflammation.
Your primary care doctor will likely conduct tests to pinpoint the kind of arthritis you might have. Imaging tests can also be used to determine the severity of arthritis.
For most people, a diagnosis of OA begins with a medical history and a physical exam. The physical exam will look for:
- noises when you move your joints
- swelling in the joints
- loss of range of motion
- tenderness in the joints
- pain during movement
Your doctor will also ask questions about when you have pain and how symptoms are affecting your daily life.
Imaging Tests for Osteoarthritis | Imaging
Imaging tests are important both for diagnosing OA and assessing its severity.
An X-ray can’t show cartilage loss directly. However, it can show changes in the spacing between the bones. This is one of the most obvious signs of OA. As cartilage degrades, the bones move closer together.
X-rays can also allow doctors to identify:
- excess fluid in the joint
- bone damage
- bone spurs
Bone spurs are growths at the end of joints. They can irritate surrounding tissues.
X-rays may not show early destructive changes that are better seen with MRI technology. However, they are often used to track the progression of OA.
Magnetic Resonance Imaging
Using magnetic resonance imaging (MRI), your doctor can see soft tissue damage. It is possible to directly visualize changes not only in bone but also in:
MRI uses a magnetic field and radio waves to create detailed, three-dimensional images of tissues.
Most cases of OA are diagnosed with physical exams and imaging tests. However, lab tests can sometimes be useful in ruling out other causes of joint pain.
Blood and urine tests can not diagnose OA. However, they can be used to help confirm a diagnosis by ruling out other causes of arthritis such as:
- another type of arthritis (infectious, autoimmune, inflammatory, metabolic)
- other health problems (endocrine disorders, autoimmune diseases)
Blood tests can be used to identify:
- white cell counts
- inflammatory markers
- specific antibodies associated with RA
Urine tests can check for levels of uric acid and other markers of inflammation.
Joint Fluid Analysis
Joint fluid is also called synovial fluid. It can be obtained by inserting a needle into the joint space. The fluid can be examined for markers of inflammation. It can also identify other causes of joint inflammation, such as infection or gout.