The shoulder is made up of three bones: the upper arm bone (humerus), shoulder blade (scapula), and collarbone (clavicle). The shoulder is a ball-and-socket joint where the ball (or head) of the humerus fits into the socket of the scapula. The socket is called a glenoid. The parts of the bones that come in contact with each other are covered with cartilage that protects the bones and allow them to move easily. There is also a smooth tissue membrane that covers all of the other areas inside the shoulder that makes fluid that lubricates the cartilage and eliminates friction in the shoulder. In total shoulder joint replacement arthroplasty, the damaged parts of the shoulder are removed and replaced with a prosthetic. This involves the replacement of both the ball and socket.
Common Causes of Total Shoulder Replacement
There are many conditions that can cause the shoulder to be painful and become disabled, and lead to needing total shoulder joint replacement surgery:
- Post-traumatic Arthritis: Fractures of the bones that make up the shoulder or tears of the shoulder tendons or ligaments may damage the articular cartilage over time. This causes shoulder pain and limits shoulder function.
- Avascular Necrosis (Osteonecrosis): Painful condition that occurs when the blood supply to the bone is disrupted. Since bone cells die without a blood supply, osteonecrosis can ultimately cause destruction of the shoulder joint and lead to arthritis.
- Rheumatoid Arthritis: This is a disease in which the synovial membrane that surrounds the joint becomes inflamed and thickened. This chronic inflammation can damage the cartilage and eventually cause cartilage loss, pain, and stiffness.
- Osteoarthritis (Degenerative Joint Disease): This is an age-related, wear and tear, type of arthritis that usually occurs in people 50 years of age and older; however, it may occur in younger people, too. The cartilage that cushions the bones of the shoulder softens and wears away. The bones then rub against one another and cause the shoulder joint to become stiff and painful.
- Rotator Cuff Tear Arthropathy: A patient with a large rotator cuff tear for a considerable amount of time may develop this arthropathy. Changes in the shoulder joint due to the rotator cuff tear may lead to arthritis and destruction of the joint cartilage.
- Severe Fractures: A severe fracture of the shoulder can be difficult for a surgeon to put pieces of bone back together. Also the blood supply to the fractured bones can be interrupted.
People who benefit from shoulder replacement surgery often have:
- Severe shoulder pain that affects everyday activities, such as reaching into a cabinet, getting dressed, bathing, using the restroom, etc.
- Moderate to severe pain while resting, preventing a good night’s rest
- Loss of motion and strength
- Failure to improve with conservative treatments such as physical therapy, medications, and injections
If it is determined that total shoulder joint replacement surgery is needed, further evaluations like physical examinations and diagnostic tests may be necessary to determine the extent of the damage as well as planning the surgery.
Total shoulder replacement surgery replaces damaged parts of the shoulder with artificial components. There are different types of shoulder replacement. Your surgeon will evaluate your situation and recommend a treatment option that is best for you.
- Total Shoulder Replacement involves replacing the arthritic joint surfaces where a plastic “cup” is placed into the shoulder socket (glenoid) and a metal “ball” is attached to the upper arm bone (humerus). Patients with bone-on-bone osteoarthritis and an intact rotator cuff are generally good candidates for traditional total shoulder replacement.
- Stemmed Hemiarthroplasty is a partial shoulder replacement that involves only replacing the “ball” of the upper arm (humerus). Hemiarthroplasty is recommended if:
- The humeral head is severely fractured but the socket is normal
- If arthritis only affects the head of the humerus
- For shoulders with severely weakened bone in the glenoid (socket)
- For severely torn rotator cuff tendons accompanied with arthritis
- Reverse Total Shoulder Replacement switches the location of the socket and metal ball, where the metal ball is placed into the shoulder socket and the plastic cup is attached to the upper arm bone. Reverse total shoulder replacement is used for people with completely torn rotator cuffs accompanied by severe arm weakness, had a previous shoulder replacement that failed, or have severe arthritis accompanied by a torn rotator cuff.
After surgery, your arm will be in a sling for two to four weeks to protect your shoulder. A physical therapy program will begin soon after surgery to help regain shoulder strength and improve range of motion and flexibility in the shoulder joint. Follow the therapy program and home exercises as prescribed by your physician. You may need to do the exercises two to three times a day for a month or more.Some common restrictions following surgery include:
- You will not be able to drive for two to four weeks after surgery.
- Don’t use your arm to push yourself up in bed or from a chair.
- Don’t overdo it – reduced pain in the shoulder after surgery can result in a false security of healing. Early overuse of the shoulder may result is severe limitations of motion long term.
- Don’t lift anything heavier than a glass of water for the first two to four weeks.
- Don’t lift your arm straight out to the side or place it behind your back for the first six weeks after surgery.
Reverse Total Shoulder Surgery
Conventional shoulder replacement mimics the normal anatomy of the shoulder, where a plastic “cup” is placed into the shoulder socket (glenoid) and a metal “ball” is attached to the upper arm bone (humerus). A reverse total shoulder replacement switches the location of the socket and metal ball, where the metal ball is placed into the shoulder socket and the plastic cup is attached to the upper arm bone.
The main purpose for a reverse total shoulder is to restore pain-free motion and function to the shoulder, and is used as an alternative surgery option for patients with:
- A completely torn rotator cuff that cannot be repaired, because a reverse total shoulder replacement relies on the deltoid muscles instead of the rotator cuff to power and move the joint.
- A previous shoulder replacement that was unsuccessful.
- Severe arthritis accompanied by a torn rotator cuff.
- Inability to lift your arm away from your body or over your head.
- Vascular damage such as vascular necrosis or osteonecrosis.
Your physician will assess any degenerative changes to the shoulder joint by conducting a physical exam. During the physical exam, your physician will perform arm and shoulder movements to check your muscle strength, joint motion, and joint stability. X-rays help determine the condition of the shoulder bones and articular cartilage. Advanced imaging tests, such as a CT scan or MRI, will show images of soft tissue (muscles, ligaments, tendons) within the shoulder joint.
Following your procedure, you can expect to stay in the hospital for one to two days. You will wear an arm sling for support, and will have restrictions on shoulder movement for about three weeks. Physical therapy will play an important role in helping you regain motion, strength, stability, and coordination to the shoulder joint. Recovery from reverse total shoulder replacement is different for each patient. It usually takes several weeks to recover completely from surgery.