Shoulder anatomy is complex and susceptible to a variety of problems. To make a shoulder arthritis diagnosis, a doctor must rule out other common potential sources of pain, such as shoulder bursitis, shoulder impingement, rotator cuff tears or other common shoulder problems.
- Explore the symptoms and treatments for the most common type of osteoarthritis in the shoulder: Acromioclavicular (AC Joint) Osteoarthritis
No single test can definitively diagnose osteoarthritis of the shoulder, so physicians use a comprehensive approach that is verified by diagnostic imaging to arrive at a clinical diagnosis.
It is important to note that most individuals over age 50 will have signs of osteoarthritis in their major joints that can be seen on an x-ray, but most will have no symptoms. Therefore, diagnostic studies alone (such as an x-ray or MRI) do not provide a diagnosis.
To make an accurate diagnosis a number of investigative tools are employed:
Patient interview. A doctor will ask about work and lifestyle activities and previous injuries to the shoulder. The doctor will also ask a patient about family history and 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.
Physical exam. A doctor will physically examine the patient’s shoulder, noting any signs of previous injury, tenderness and pain points, 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.
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Testing. The patient consultation and physical exam provides the doctor with enough information to rule out certain shoulder pathologies. Follow-up tests are usually included as part of the diagnostic process both to gain further information about the extent of the shoulder arthritis and/or to rule out other possible causes of the patient’s pain.
Injection of a local anesthetic. Injecting a local anesthetic such as lidocaine directly into the glenohumeral joint is one of the most effective ways to test for arthritis.5 If the pain is temporarily relieved after the injection, then a diagnosis of shoulder arthritis is confirmed. If the pain persists, another shoulder problem, such as a rotator cuff injury, is a more likely cause of the patient’s symptoms.
X-rays. X-rays can show if there is a loss of joint space in the glenohumeral joint. 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. However, some people may have x-rays that show significant signs of shoulder osteoarthritis and experience no pain, while others may have x-rays that show few signs of shoulder osteoarthritis and have significant pain. Minor cartilage damage or bone spurs can translate into a lot of pain if either is in a sensitive spot. Therefore, the x-ray is just one tool to be used in conjunction with the patient interview and physical exam.
MRI. Magnetic Resonance Imaging (MRI) may be ordered to provide additional detail, as this test provides images of the soft tissue (ligaments, tendons and muscle) as well as bone. This more detailed image of the shoulder joints can be helpful if x-rays of the shoulder are inconclusive or if the doctor suspects symptoms are due to something other than osteoarthritis, such as damage to the shoulder’s labrum or rotator cuff. However, an MRI is more time consuming - requiring the patient to remain perfectly still for about 30 minutes - and is more expensive than an x-ray. An MRI is not necessary in many cases.
Lab tests. Lab tests cannot identify the presence of shoulder osteoarthritis, but they can be used to rule out other problems, such as infection or gout, which can also cause shoulder pain. Lab tests may require a blood draw or an aspiration of the shoulder joint.
- Docimo S., Kornitsky, D., Futterman B., Elkowitz DE, “Surgical Treatment for acromioclavicular joint osteoarthritis: patient selection, surgical options, complications and outcome” Curr Rev Musculoskelet Med (2008) 1:154-160. Accessed September 12, 2011, http://www.ncbi.nlm.nih.gov