Shoulder Joint Replacement
Total Shoulder Arthroplasty
The shoulder is a highly movable body joint that allows various movements of the arm. It is a ball and socket joint, where the head of the humerus (upper arm bone) articulates with the socket of the scapula (shoulder blade) called the glenoid. The two articulating surfaces of the bones are covered with cartilage, which prevents friction between the moving bones. The cartilage is lubricated by synovial fluid. Tendons and ligaments around the shoulder joint provide strength and stability to the joint.
When the cartilage is damaged, the two bones rub against each other resulting in pain, swelling and stiffness of the joint (osteoarthritis).
Total shoulder replacement surgery is performed to relieve these symptoms. In this surgery, the damaged articulating parts of the shoulder joint are removed and replaced with artificial prostheses. Replacement of both the humeral head and the socket is called a total shoulder replacement.
Total shoulder joint replacement surgery is indicated for conditions such as osteoarthritis or rheumatoid arthritis when medication, injections, physical therapy, and activity changes do not help relieve pain. Your doctor recommends surgery when you have the following symptoms:
- Severe shoulder pain that restricts daily activities
- Moderate to severe pain during rest
- Weakness and/or loss of motion
To decide whether total shoulder replacement is a good option for you the surgeon will evaluate your condition thoroughly.
Your surgeon reviews your medical history and performs a physical examination of your shoulder to assess the extent of mobility and pain. Imaging tests such as X-ray or MRI (magnetic resonance imaging) are ordered.
The surgery is done under regional or general anesthesia. An incision is made over the affected shoulder and the underlying muscles are separated to expose the shoulder joint. The surgery may be performed as open surgery, where a large incision is made, or minimally invasive, where small incisions are made to insert an arthroscope (a thin tube with a camera and light source) and surgical tools.
The upper arm bone (humerus) is separated from the glenoid socket of the shoulder bone. The arthritic or damaged humeral head is cut and the humerus bone is hollowed out and filled with cement. A metal ball with a stem, is gently press fit into the humerus.
Next, the arthritic part of the socket is prepared. The plastic glenoid component is fixed in the shoulder bone.
After the artificial components are implanted, the joint capsule is stitched and the wound is closed.
After the surgery, pain medications and antibiotics are prescribed to control pain and prevent infection. Your arm may be secured in a sling or cast. The rehabilitation program includes physical therapy, which is started soon after the surgery and is very important to strengthen and provide mobility to the shoulder. You may be able to perform gentle daily activities two to six weeks after surgery.
Risk and complications
As with any major surgery, there may be potential risks involved:
- Anesthetic complications such as nausea, dizziness and vomiting
- Infection of the wound
- Dislocation, requiring repeat surgery
- Damage to blood vessels, nerves or muscles
- Failure to relieve pain
- Pulmonary embolism
- Wear and tear of prosthesis
Reverse Shoulder Arthroplasty
Reverse Total Shoulder Arthroplasty is a type of Shoulder Joint Replacement surgery which addresses not only glenohumeral arthritis, but also shoulder instability. With a traditional Total Shoulder Replacement or arthroplasty, the arthritic surfaces of the glenohumeral joint are smoothed and a prosthetic cup is placed in the glenoid or shoulder socket and a prosthetic ball is inserted into the end of the humerus or arm bone to replace the “ball and socket” joint. This type of surgery is very successful at relieving arthritic pain in patients who have intact rotator cuff tendons and other soft tissue structures to support the new prosthetics and provide good range of motion.
Patients who have shoulder instability due to deficient rotator cuff tendons may benefit from a Reverse or Inverse Total Shoulder Arthroplasty. This surgery is designed specifically for the treatment of glenohumeral arthritis when it is associated with irreparable rotator cuff damage, complex fractures or to revise a failed conventional Total Shoulder Arthroplasty as a result of deficient rotator cuff tendons. Reverse Total Shoulder Arthroplasty reverses the placement of the prosthetics. Instead of the prosthetic cup being placed in the glenoid socket, it is placed at the end of the arm bone or humerus. And, instead of the prosthetic ball begin placed at the end of the arm bone, the ball is placed in the glenoid socket. By reversing the location of the prosthetics, the shoulder’s center of rotation is altered enabling the deltoid muscle to compensate for the deficient rotator cuff. As a result, the deltoid muscle becomes the primary elevator of the shoulder joint enabling patients to elevate their shoulder and often to raise their arm overhead.