Shoulder anatomy
The shoulder joint is made of three bones:
- The head of the upper arm bone called the humerus
- The shoulder blade called the scapula
- The collarbone called the clavicle
There are four joints in the shoulder. While OA commonly affects the AC joint and the GH joint, it also affects the SC joint.
- The glenohumeral joint (GH) is a ball and socket joint made of the head of the humerus which sits in the socket called the glenoid, that is part of the shoulder blade.
- The Acromioclavicular joint (AC joint) is made of the clavicle where it meets the acromion or tip of the shoulder.
- The Sternoclavicular joint (SC joint) is located where the clavicle meets the breast bone or sternum. It supports the shoulder and connects the arm to the body. OA of this area is common occurring in about 90% of people over age 60. While common, OA in this joint generally causes no symptoms.
- The Scapulothoracic joint (ST joint) is not a true joint but does provide stability for up and down arm movement. It is generally affected by bursitis. Bursitis is inflammation of the bursa that cushion and protect the area between the scapula and the chest wall from friction.
What is osteoarthritis of the shoulder?
OA of the shoulder is a progressive destructive joint disease often called “wear and tear” arthritis. It causes the gradual wearing away of the protective articular cartilage at the ends of the bones due to chronic inflammation. Loss of the articular cartilage creates friction in the joint which results in pain and stiffness; and eventually reduced or lost mobility and function. Shoulder OA can significantly impair quality of life. Shoulder OA is a leading cause of pain and disability in one in three people over the age of 50 but can affect younger individuals who have suffered a traumatic injury to the shoulder.
What causes shoulder OA?
Shoulder OA is often genetically determined and is age-related. Women are affected more often than men. Post-traumatic shoulder OA is the result of a previous injury from sports, occupational or accidental injury, or the result of repeated dislocation, infection and rotator cuff tears.
What are the symptoms?
When OA affects the AC joint, the pain is on the top of the shoulder and can radiate down the side of the neck. AC joint OA can cause rotator cuff tears. If the GH joint is affected, the pain is felt in the back of the shoulder as a deep ache. Shoulder OA can also cause tenderness, a grating sensation, swelling and interfere with function. As noted, OA of the SC joint usually does not cause symptoms.
How is shoulder OA diagnosed?
Dr. Joe Cooper will listen to your complaints and symptoms, review your medical history and all past and current shoulder injuries; and conduct a thorough examination of your shoulder joint testing range of motion and strength. He will look for signs that indicate arthritis including tenderness in the joint, swelling, and crepitus (grating sensation). X-rays will show changes in the bones, joint space narrowing and bone spurs. An MRI will be ordered to assess the health of the rotator cuff and other soft tissues.
What are the treatments for shoulder OA?
Pain management, preservation of the joint and mobility are the focus of treatment. Conservative measures include rest, ice and heat therapy, activity modification, anti-inflammatory over the counter medications, physical therapy, and steroid and hyaluronic acid injections to treat persistent shoulder pain.
When conservative measures fail to control symptoms and depending upon your age and level of activity, Dr. Cooper may recommend shoulder arthroscopy to view and clean out the joint to remove pieces of frayed cartilage and bone to improve function and decrease pain.
When individuals have severe and disabling OA, Dr. Cooper may recommend a partial or total joint replacement. A partial replacement replaces the head of the upper arm bone. A total shoulder replaces the entire joint.
OA is a chronic degenerative disease with no cure. The goal of treatment is to relieve pain, preserve mobility and prevent disability. Dr. Joe Cooper is a shoulder expert who can help you live better with shoulder OA and when needed provide state-of-the-art procedures to restore your mobility and relieve your pain.
