Shoulder aches are far from an unusual complaint. In fact, up to 70 percent of people will experience shoulder pain at some point in their life, with arthritis being one of the main causes, according to a study of shoulder complaints in a general population. 

But determining which type of arthritis is responsible for your aching shoulders can sometimes be tricky, and doctors must rule out a number of other conditions (besides arthritis) that affect the shoulders to make a diagnosis. 

Arthritis can affect either of the joints in your shoulder. The glenohumeral joint is the larger of the two; this is where the top of the humerus (the bone in your upper arm) meets the collarbone to form a ball-and-socket joint. The other — the acromioclavicular joint — is where the collarbone meets the shoulder blade.

If you’re wondering if your shoulder pain could be due to arthritis, keep reading.

Types of Arthritis in the Shoulders

Shoulder involvement can occur in two of the most common forms of arthritis: osteoarthritis and rheumatoid arthritis. 

Osteoarthritis in the Shoulder

“When we see OA of the shoulders, it’s usually the result of past trauma to the shoulders,” says Darush Rahmani, DO, FACP, FACR, a rheumatologist at Austin Regional Clinic in Texas. “It can also be the result of years of wear and tear, so you might see it in someone who has done manual labor, for example.”

Rheumatoid Arthritis in the Shoulder

While RA most commonly affects the smaller joints in the fingers, hands, and feet, Dr. Rahmani says that over 50 percent of patients with RA do ultimately develop shoulder involvement.

“OA and RA share similar symptoms, such as pain and limited pain of motion. But an inflammatory arthritis such as RA is more likely to be suspected if the shoulder is red or swollen, other joints are affected, and the patient has fatigue or a fever,” he explains. 

Shoulder pain can also occur in other, less common forms of inflammatory arthritis, such as psoriatic arthritis, ankylosing spondylitis, and gout. There are a few other types of arthritis that your doctor will need to consider as well, including:

  • Post-traumatic arthritis:This can develop years after an injury to the shoulder. Post-traumatic arthritis can present as osteoarthritis (as Dr. Rahmani described above) or as a form of inflammatory arthritis such as gout. 
  • Rotator cuff tear arthropathy: If you experienced a large tear to your rotator cuff in the past, you may have developed this form of degenerative arthritis. A tear can cause two bones in the shoulder — the top of the humerus and the underside of the acromion — to rub against each other, resulting in damage to the bones.
  • Avascular necrosis: In avascular necrosis, death of bone tissue occurs due to lack of blood supply. Possible causes include a broken bone, dislocated joint, high-dose steroid use, heavy alcohol consumption, sickle cell disease, and traumatic injury to the shoulder. 

Other Possible Causes of Shoulder Pain

Not all shoulder pain is due to arthritis, of course. Visit our sister site PainSpot to take a personalized quiz to see what else could be causing your shoulder pain.

A condition called frozen shoulder shares several symptoms with osteoarthritis, Dr. Rahmani says, including pain, stiffness, and limited range of motion. Frozen shoulder occurs when the tissue that surrounds your shoulder joint (called the shoulder capsule) becomes thick and tight. But unlike OA, which is progressive, frozen shoulder resolves over time, usually within one to three years. 

Bursitis can resemble rheumatoid arthritis because it causes redness and swelling. However, bursitis is not an autoimmune disease like RA; rather, it develops when the bursae (small, fluid-filled sacs that cushion your bones, tendons, and ligaments) become inflamed. Bursitis can often be blamed on overuse or injury of a joint.

Other medical conditions that don’t directly affect the shoulder can cause referred pain in the shoulders. Some examples include shingles, cervical nerve impingement, and blood clots in the lungs, says Dr. Rahmani.

“In addition, any condition that affects the diaphragm, such as an injured spleen or gallbladder problems, can cause referred pain in the shoulders because they irritate the nerves that run from the diaphragm to the shoulders,” he explains.

Doctors may suspect these indirect causes of shoulder pain depending on what they see in your physical exam.

“If someone reports pain but has good range of motion, that’s when you have to think outside the box,” Dr. Rahmani says.

How Doctors Diagnose Arthritis Shoulder Pain

To determine whether OA or an inflammatory arthritis like RA is responsible for your shoulder pain, your doctor will rely on your medical history, a physical exam, and blood and imaging tests. You can also expect your doctor to ask about your lifestyle.

“If someone comes to me with shoulder pain who says he’s a swimmer and has recently increased his activity level, for example, I’m more inclined to think it’s OA,” Dr. Rahmani says.

The location of your shoulder pain also provides clues, he adds: “People with RA will have a more diffuse pain throughout the shoulder, while those with OA have tenderness in one area.”

If your doctor suspects RA or another type of inflammatory arthritis, they will order blood tests to look for the presence of certain antibodies, such as rheumatoid factor and anti-CCP, which help identify these conditions.

If there’s fluid in your joint, your doctor may take a sample and send it to a lab for analysis.

“This gives your doctor a lot of information,” Dr. Rahmani says. “The white blood cell count can indicate whether you have OA or RA and how inflamed the shoulder is, and the fluid itself may reveal gout crystals.”

When it comes to imaging tests, he says an MRI provides the most information.

“We typically start with X-rays but they aren’t always helpful because you don’t see structures such as the tendons that allow you to fully evaluate the shoulder,” Dr. Rahmani explains. “Ultrasound reveals more and it’s also cost-effective, but not everyone is trained to do a complete evaluation of the shoulder using an ultrasound.”

How Shoulder Arthritis Is Treated

If you’re diagnosed with OA, over-the-counter or prescription pain relievers and analgesic balms such as Biofreeze and Aspercreme help ease your aches. Cortisone injections can quickly alleviate intense, acute pain. Your doctor may also prescribe physical therapy, where you’ll learn exercises that strengthen the shoulders and improve range of motion.

Physical therapy can also helpful for those RA and other forms of inflammatory arthritis. These patients also benefit from OTC and prescription pain relievers, specifically NSAIDs. Inflammatory arthritis — which typically affects multiple joints in addition to the shoulders — is typically managed with disease-modifying drugs and/or biologics. These help stop the underlying, systemic inflammation that can cause long-term joint damage if left untreated.

In some cases, surgery may be necessary for patients who haven’t responded to nonsurgical treatments. For milder, glenohumeral cases of OA, a surgeon removes any bone spurs or pieces of tissue that are impeding the joint’s function. People with more advanced OA may require shoulder replacement surgery.

Those with RA may also need to consider surgery if medications and therapy haven’t helped and joint deterioration becomes severe. Options include shoulder replacement surgery, fusion of the affected joints (arthrodesis), and partial removal of the inflamed synovium that surrounds the shoulder joint (synovectomy).

At-Home Therapies for Shoulder Arthritis

In addition to performing the exercises recommended by your physical therapist, you can help relieve acute pain with ice or heat. Heat therapy may be best in the morning for loosening up your stiff shoulders, while ice therapy may be more helpful in the evening to ease aches following a day’s worth of activity.

Depending on the severity of your shoulder arthritis, you may want to consider using assistive devices to perform tasks that have become difficult. One popular tool is a reacher, a long rod with pincers on one end that allows you to remove and replace items from high places without having to raise your arm. Zipper pulls can be useful when you’re getting dressed, while dressing sticks, which have a small hook on one end, can help you pull on sleeves and other tasks.

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