The decision to perform an anatomic shoulder replacement versus a reverse shoulder replacement is based on the status or health of the rotator cuff. One of the main functions of the rotator cuff is to keep the ball in contact with the socket to act as a pivot point when elevating the arm. Without this, the ball slips up and out of the socket and it is very difficult to lift the arm. A reverse total shoulder replacement switches the normal anatomic relationship and attaches a ‘ball’ to the socket and a cup at the top of the arm bone. This new, reversed, position keeps the joint in position and the cup pivots on the ball. The function is greatly improved with a reverse total shoulder in patients without a good rotator cuff. In fact, a reverse shoulder replacement is often performed on patients who do not have significant arthritis but have an unrepairable rotator cuff.
Post-operative problems with shoulder replacements most often occur on the socket side of the joint. This is because the ball is attached to a relatively small socket and it is important to place the socket component accurately. To avoid these complications, a pre-operative CT scan of the shoulder is obtained and used to create a 3D computer model that is used for surgical planning. Computer planning allows the surgeon to prepare and select appropriate implants ahead of time. The 3D computer model is also used to create a custom jig for the patients shoulder that allows accurate placement of the socket component without difficulty.
Shoulder replacement surgery is done either as a same-day surgery or single overnight stay. For pain control, patients typically receive a nerve block before surgery that numbs the shoulder and entire arm . This block can last anywhere between 18-24 hours. After the surgical procedure, the arm is placed in a shoulder immobilizer for safety and comfort . During the first two weeks after discharge, a home health nurse will make regular visits to the patients home to check the surgical incision and for early mobilization and exercises. Formal or outpatient physical therapy usually does not begin until about 4 weeks after surgery and the rehabilitation is complete at about 3 months after surgery.
Just like other joint replacement surgeries, shoulder replacement surgery provides reliable pain relief of joint arthritis pain. While shoulder motion and strength are often improved after a shoulder replacement, the most reliable predictor of post-operative range of motion is a patient’s preoperative range of motion. The reverse total shoulder has the additional benefit of improving shoulder function by taking the place of an insufficient rotator cuff. Many patients achieve their desired level of function and return to playing golf, tennis, etc.