To accurately diagnose glenohumeral osteoarthritis (shoulder arthritis), a health professional will interview the patient, conduct a physical exam, and if necessary, order medical imaging and lab testing. This diagnostic process can help rule out other potential sources of shoulder pain, such as shoulder bursitis, shoulder impingement, frozen shoulder and rotator cuff tears.
A patient may be asked to describe his or her work, daily and recreational activities, and history of shoulder injuries. The doctor will also ask a patient to describe the onset of his or her shoulder symptoms, the pattern of pain, limitations to range of motion, as well as what makes the symptoms better or worse. A patient’s reported symptoms are important for diagnosis and treatment.
A doctor will physically examine the patient’s shoulder, noting any signs of previous injury; points of tenderness and pain; and muscle weakness. He or she will also evaluate the shoulder’s passive (assisted) and active range of motion.
A doctor may also look for problems in other joints, as that may indicate an inflammatory condition such as rheumatoid arthritis or gout. In addition, the patient may be evaluated for problems in the neck, midback, elbow, and other joints that can cause referred pain in the shoulder.
The patient interview and physical exam may provide a doctor with enough information to diagnose shoulder arthritis. In other cases, medical imaging and/or lab testing will be ordered to help rule out other possible problems.
A physician may order medical imaging to gauge the severity of the shoulder arthritis and/or to rule out other possible causes of the patient’s pain.
- X-rays. X-rays can show if there is a loss of space between the head of the humerus and the glenoid (socket). A loss of joint space indicates a loss of cartilage. An x-ray can also show bone spurs and other malformations of the humeral head, a sign that the bones have tried to compensate for cartilage loss with extra bone growth.
- MRI. Magnetic Resonance Imaging (MRI) can provide detailed images of a shoulder’s soft tissue (ligaments, tendons and muscle) as well as bone. An MRI arthrogram, which involves using an injected contrast fluid, is the most common advance imaging ordered for the shoulder. An MRI arthrogram will show a torn glenoid labrum, a frequent source of shoulder pain. An MRI or MRI arthrogram can be helpful if x-rays are inconclusive or if the doctor suspects symptoms are due to something other than osteoarthritis, such as damage to the shoulder’s rotator cuff. An MRI requires the patient to remain perfectly still for about 30 minutes and typically costs more than an x-ray.
- CT Scans. A computerized tomography (CT) scan takes multiple cross-section x-ray images to view structures inside the body, providing a more detailed view of the shoulder than a standard x-ray. A CT scan can help a doctor visualize the shoulder socket and other joint surfaces and identify bony defects that could affect surgery.
- Ultrasound. Like and MRI, an ultrasound exam can show damage to soft tissues, such as the rotator cuff. MRI produces more detailed images than ultrasound. However, during an ultrasound exam, a patient can be asked to rotate the shoulder, allowing the health care professional to see how dynamic movement affects the shoulder’s tissues.
Most individuals over age 50 will have signs of osteoarthritis in their major joints—including their shoulders—that can be seen on medical imaging, but most will have no symptoms. Therefore, medical imaging alone cannot provide a diagnosis.
While shoulder osteoarthritis cannot be verified with lab testing, it can be used to help rule out other conditions that can cause shoulder pain, such as rheumatoid arthritis, ankylosing spondylitis, an infection, or gout. Lab tests may require a blood draw or an aspiration of the shoulder joint.
Once shoulder osteoarthritis has been diagnosed, a treatment program can begin.