Arthritis of the shoulder
Arthritis causes inflammation in and around joints. In the shoulder, arthritis can cause pain and stiffness that make it more difficult for the shoulder to move in all the directions it would normally move.
The type of arthritis that most often affects the shoulder is called osteoarthritis. There is no cure for osteoarthritis, but it can be treated with medications, lifestyle changes, or surgery.
Also sometimes known as “wear-and-tear” arthritis, osteoarthritis causes the cartilage in the joint to break down. Cartilage is the smooth tissue that covers the ends of the bones in a joint and allows the bones to glide against each other. When the cartilage is damaged by osteoarthritis, the bones begin to rub against each other instead of gliding smoothly.
From the outside, the shoulder appears to be one joint. But the shoulder is actually made up of two joints that are formed by three bones—the upper arm bone, the shoulder blade, and the collarbone.
The upper arm bone fits into a socket in the shoulder blade. That joint, known as the glenohumeral joint, is held into place by a group of muscles and tendons known as the rotator cuff.
The other joint in the shoulder is located where the shoulder blade connects to the collarbone and is called the acromioclavicular joint, or AC joint.
Both joints in the shoulder can be affected by arthritis.
Symptoms of arthritis of the shoulder usually begin slowly and then get worse over time. Symptoms include:
- Pain in the back or top of the shoulder that sometimes extends to the neck
- Limited range of movement
- A grinding or popping sound while moving the shoulder
Causes and risk factors
The cause of osteoarthritis is not known. Some factors that increase the risk of osteoarthritis in the shoulder include:
- Past injury to the shoulder
- Overuse of the shoulder, such as while working or playing sports
- Family history of osteoarthritis
Nonsurgical treatments of osteoarthritis include:
- Resting the shoulder and avoiding certain movements
- Physical therapy exercises, which can sometimes help with range of movement in cases of mild arthritis
- Anti-inflammatory medication such as ibuprofen to reduce swelling
- An injection of corticosteroid medication into the shoulder, which can be helpful for some patients
If nonsurgical treatment doesn’t relieve the pain of arthritis in your shoulder, your doctor may recommend one of a number of shoulder surgery options:
- Early arthritis in the glenohumeral joint can sometimes be treated with arthroscopy. The surgeon inserts a small camera, called an arthroscope, into the shoulder and uses small surgical instruments to clean out damaged cartilage. This relieves pain, but it doesn’t cure the arthritis, so more surgery may be required in the future if the pain returns. In cases of advanced or more severe arthritis, arthroscopy has limited long-term results.
- More severe cases of arthritis in the glenohumeral joint may be treated with a shoulder joint replacement, also known as total shoulder arthroplasty. In total shoulder arthroplasty, the head of the upper arm bone and the socket in the shoulder blade are replaced with a metal ball and a plastic socket. Sometimes only the head of the upper arm bone needs to be replaced.
- If the rotator cuff has a large tear that can’t be repaired, or if the ball or socket joint is significantly worn, the new ball and socket can be reversed in a procedure known as reverse total shoulder arthroplasty. The socket is implanted at the end of the upper arm bone, and the ball is implanted in the end of the shoulder blade. This allows the new shoulder joint to rely on different muscles for movement.
- Arthritis in the AC joint can be treated with resection arthroplasty, in which a small part of the collar bone is removed.