Shoulder Osteoarthritis Causes

Knowing the underlying cause of shoulder arthritis may help guide treatment recommendations. Many risk factors exist, and evidence suggests the most significant are a previous shoulder injury or overuse.

Risk Factors for Shoulder Arthritis

Experts estimate 90% of people who have shoulder arthritis have one or more risk factors.^, Possible risk factors include:

• Shoulder joint injury. A broken bone, dislocation (when the humeral head pops out of its socket), or other serious trauma or surgery can cause damage to the shoulder joint. The damage can eventually lead to shoulder osteoarthritis. Symptoms may not appear until years after the trauma.
• Shoulder joint stress and chronic injury. People whose jobs or recreational lifestyle require spending a lot of time lifting objects overhead, throwing, or doing high-impact activities—such as chopping wood or using an air-hammer—can experience “mini-traumas” in their shoulder joints. These mini-traumas increase the risk of developing shoulder osteoarthritis.
• Advanced age. Shoulder arthritis most commonly affects people over the age of 50. The prevalence of symptomatic osteoarthritis increases with age because, over time, the shoulder joints experience wear and tear that can cause cartilage to thin and becomes less flexible.
• Congenital defect. Poor bone alignment, which also makes some people more likely to suffer shoulder dislocations, can increase the risk of developing shoulder osteoarthritis.
• Autoimmune arthritis or other illness. Autoimmune arthritis, such as rheumatoid arthritis, or a history of gout, septic arthritis, or other metabolic disorder can increase the risk of shoulder osteoarthritis.
• Gender. Glenohumeral arthritis is more common in women.

• Obesity. While the shoulder is not a weight-bearing joint, research suggests that people who are overweight are more likely to get shoulder arthritis. Obesity is associated with low-grade, systemic (body-wide) inflammation, which may contribute to the development of osteoarthritis.^, (Obesity is defined as a BMI ≥ 30.)
• Genetics. Similar to height and hair color, the likelihood of a person developing shoulder osteoarthritis is influenced by genetics. While the exact extent of genetic factors is not known, a woman whose mother has shoulder osteoarthritis is more likely to develop the disease than another woman whose mother did not have shoulder osteoarthritis.

It is possible for a person without any of the above risk factors to develop the shoulder arthritis. Likewise, a person with all of the above characteristics may never develop it.