In 2011, more than 50 million people in the United States reported that they had been diagnosed with some form of arthritis, according to the National Health Interview Survey. Simply defined, arthritis is inflammation of one or more of your joints. In a diseased shoulder, inflammation causes pain and stiffness.
Although there is no cure for arthritis of the shoulder, there are many treatment options available. Using these, most people with arthritis are able to manage pain and stay active.
Your shoulder is made up of three bones: your upper arm bone (humerus), your shoulder blade (scapula), and your collarbone (clavicle).
The head of your upper arm bone fits into a rounded socket in your shoulder blade. This socket is called the glenoid. A combination of muscles and tendons keeps your arm bone centered in your shoulder socket. These tissues are called the rotator cuff.
There are two joints in the shoulder, and both may be affected by arthritis. One joint is located where the clavicle meets the tip of the shoulder blade (acromion). This is called the acromioclavicular (AC) joint.
Where the head of the humerus fits into the scapula is called the glenohumeral joint.
To provide you with effective treatment, your physician will need to determine which joint is affected and what type of arthritis you have.
Five major types of arthritis typically affect the shoulder.
- Rheumatoid Arthritis
- Posttraumatic Arthritis
- Rotator Cuff Tear Arthropathy
- Avascular Necrosis
Pain. The most common symptom of arthritis of the shoulder is pain, which is aggravated by activity and progressively worsens.
If the glenohumeral shoulder joint is affected, the pain is centered in the back of the shoulder and may intensify with changes in the weather. Patients complain of an ache deep in the joint.
The pain of arthritis in the acromioclavicular (AC) joint is focused on the top of the shoulder. This pain can sometimes radiate or travel to the side of the neck.
Someone with rheumatoid arthritis may have pain throughout the shoulder if both the glenohumeral and AC joints are affected.
Limited range of motion. Limited motion is another common symptom. It may become more difficult to lift your arm to comb your hair or reach up to a shelf. You may hear a grinding, clicking, or snapping sound (crepitus) as you move your shoulder.
Medical History and Physical Examination
After discussing your symptoms and medical history, your doctor will examine your shoulder.
During the physical examination, your doctor will look for:
- Weakness (atrophy) in the muscles
- Tenderness to touch
- Extent of passive (assisted) and active (self-directed) range of motion
- Any signs of injury to the muscles, tendons, and ligaments surrounding the joint
- Signs of previous injuries
- Involvement of other joints (an indication of rheumatoid arthritis)
- Crepitus (a grating sensation inside the joint) with movement
- Pain when pressure is placed on the joint
X-rays are imaging tests that create detailed pictures of dense structures, like bone. They can help distinguish among various forms of arthritis.
X-rays of an arthritic shoulder will show a narrowing of the joint space, changes in the bone, and the formation of bone spurs (osteophytes).
As the disease progresses, any movement of the shoulder causes pain. Night pain is common and sleeping may be difficult.