There are three bones in the shoulder, the head of the upper arm bone (the humerus), the shoulder blade (the scapula) and the collarbone (the clavicle). Articular cartilage covers the ends of these bones, provides the cushioning between bones and helps to absorb shock and reduce friction.
These three bones create two joints, the acromioclavicular (AC) joint, and the glenohumeral (GH) joint. Either or both can be affected but OA is more common in the AC joint, and usually affects people over the age of 50. The AC joint is made of the collarbone which meets the tip of the shoulder blade called the acromion.
Types of shoulder arthritis
- Osteoarthritis – the most common type of shoulder arthritis.
- Rheumatoid arthritis – a chronic autoimmune disease.
- Post-traumatic arthritis – a form of OA that develops after an injury to the joint.
- Rotator cuff tear arthropathy – caused by rotator cuff tendon tears that can’t hold the head of the upper arm bone in the socket causing the bones to rub together.
- Avascular Necrosis – a painful shoulder condition that develops when the blood supply to the upper arm bone is disrupted causing bone cells to die and destroy the shoulder joint caused by high steroid use, alcoholism traumatic fractures, and sickle cells disease.
Osteoarthritis (OA) is also called degenerative joint disease. It causes the gradual breakdown of articular cartilage. This causes friction in the joint and generates pain and stiffness which interferes with the ability to perform the daily activities of life including brushing your hair and lifting your arm. It is estimated that nearly one in three people over age 60 has some degree of shoulder osteoarthritis. Shoulder arthritis is relatively uncommon in the younger and active population, with studies showing that it affects only 1-2% of individuals aged 20 to 40 years.
What causes Osteoarthritis?
Osteoarthritis is caused by wear and tear on the joints, which can be due to a variety of factors. Heredity, obesity, and joint injuries (trauma) are all possible causes of osteoarthritis. Age-related changes in the amount of cartilage in the joint can contribute to osteoarthritis as well. Additionally, certain occupations that involve repetitive activities can put stress on the joints, leading to joint damage and consequently, osteoarthritis.
OA can affect the AC Joint or GH Joint.
- GH joint arthritis is shoulder arthritis, a degenerative joint disease that damages the articular surfaces of the head of the upper arm bone and the shoulder socket. GH joint arthritis is more common in women and patients over aged 60, and in young active patients. Symptoms are shoulder pain, loss of range of motion, and difficulty sleeping.
- AC joint arthritis is more common in weightlifters and overhead throwing athletes. It is more common with age, caused by repetitive microtraumas that lead to development of OA. Risk factors include trauma, clavicle fractures, joint instability, septic arthritis (infection in the joint) and constant overhead throwing (overuse or repetitive use).
Shoulder arthritis in the young and active patient
In younger patients, shoulder arthritis is typically caused by trauma or injury that has damaged the cartilage in the joint. Damage may be due to a single traumatic injury, such as a rotator cuff tear, a single or repeated dislocations, fractures and infections, or it may occur over time as a result of repetitive motion or strain on the shoulder that causes wearing away of the articular cartilage that covers the ends of the bones. The disease process underlying shoulder arthritis in the young and active patient is often more complex and can encompass conditions like avascular necrosis and post-traumatic changes.
How is shoulder arthritis diagnosed?
Dr. Petrigliano will ask about your symptoms, review your medical history and perform an examination of your shoulder, including palpating for pain, and testing strength, mobility, and other symptoms like crepitus, a grating sensation, swelling and tenderness. In addition, x-rays may reveal bone spurs and narrowing of the joint space which allows the bones to rub together causing pain and stiffness.
What are the treatment options?
There are good treatment options that allow patients to stay active and manage pain. Initial treatment is nonoperative management with rest, activity modification, physical therapy, NSAIDs for pain and inflammation, ultrasound-guided steroid injections and moist heat and icing.
There is no cure which means people with moderate to severe arthritis may need to consider shoulder arthroplasty also known as shoulder replacement. It is a reliable treatment option that results in both pain relief and restoration of shoulder function.
Dr. Petrigliano and colleagues offer joint preserving options for younger patients with shoulder arthritis, after nonoperative management fails, including viscosupplementation, arthroscopic debridement, microfracture, osteochondral allografts and more.
Dr. Frank Petrigliano is an orthopedic surgeon and sports medicine expert and leader in his field in Los Angeles, CA. Contact him at one of this three convenient locations to schedule a consultation and receive the correct diagnosis, all your treatment options, and expert personalized care.
At a Glance
Dr. Frank Petrigliano
- Associate Professor of Orthopaedic Surgery at USC
- Chief of the Epstein Family Center for Sports Medicine
- Team physician for the LA Kings and USC Athletics
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