Overview

Reverse shoulder arthroplasty is a highly successful shoulder replacement that can relieve pain and restore useful function in patients with advanced arthritis, irreparable rotator cuff disease, and several other complex shoulder conditions. Rather than preserving the normal ball-and-socket orientation, a reverse replacement switches the two sides of the joint: the ball is placed on the socket side and the socket is placed on the humeral side. This design allows the shoulder to function even when the rotator cuff is no longer working properly.

Joint replacement differs fundamentally from arthroscopy. Arthroscopy can remove damaged tissue, smooth rough surfaces, and repair selected problems, but it cannot restore a joint surface that has been permanently worn away. Reverse arthroplasty replaces those damaged surfaces with new prosthetic components.

When Is Reverse Shoulder Arthroplasty Recommended?

Reverse shoulder arthroplasty has become the workhorse shoulder replacement because it can successfully address a broader range of shoulder problems than an anatomic replacement. Common indications include irreparable rotator cuff tears, rotator cuff arthropathy, complex fractures, failed previous shoulder surgery, and selected older lower-demand patients. It is also used when the rotator cuff is deficient or nonfunctional and therefore cannot support an anatomic shoulder replacement.

Another important indication is pseudoparalysis. This occurs when a patient with a large rotator cuff tear loses the ability to actively raise the arm, making the arm appear almost paralyzed even though the nerves and muscles themselves are not truly paralyzed. Interestingly, the size of the tear alone does not determine whether this occurs - some patients with extremely large tears can still elevate their arm, while others cannot.

Once true pseudoparalysis is present from an irreparable rotator cuff tear, reverse shoulder arthroplasty offers the best opportunity to restore active elevation of the arm. It does not restore this ability in every patient, but many patients regain enough active motion to reach the top of their head or raise the arm above shoulder level. As with other joint replacements, surgery is usually considered when symptoms have progressed despite appropriate conservative care and pain, weakness, loss of motion, sleep disturbance, or loss of function is substantially affecting the patient's quality of life.

How the Reverse Shoulder Works

In a reverse shoulder arthroplasty, the normal relationship of the joint is intentionally reversed. A prosthetic ball is fixed to the glenoid side of the shoulder, while a socket component is placed on the humeral side. This change in mechanics allows the deltoid muscle to play a larger role in elevating and positioning the arm, which is why the procedure can restore useful shoulder function even when the rotator cuff is irreparable or deficient.

Goals of Surgery

The goals are to provide major pain relief, restore dependable shoulder function, improve motion, and allow patients to return to a more active and independent lifestyle. For many patients with severe rotator cuff dysfunction or advanced joint damage, reverse shoulder arthroplasty provides a predictable solution when joint-preserving treatment can no longer adequately address the problem.

Preoperative Planning

A preoperative CT scan is obtained for every patient. The scan allows detailed planning of implant size, alignment, position, and balance before surgery. Careful planning is particularly important in reverse arthroplasty because component position and the relationship between the reconstructed ball and socket directly influence stability, motion, and function.

Surgery and Recovery

Most reverse shoulder arthroplasties are performed as outpatient procedures. During the first six weeks, patients are encouraged to use the arm for light daily activities primarily in front of the body. I allow the arm to move somewhat outside the frame of the body - approximately as wide as you would reach to hug someone - but patients should avoid reaching behind their back.

In patients with poorer bone quality, particularly smaller, older women, I am considerably more protective. These patients may be limited to very light use of the arm for only a couple of hours each day during the early recovery period.

6 weeks: Discontinue the sling and begin unrestricted motion with light activities.
3 months: Progress to moderate activities.
6 months: Progress toward final activities.

Although there are no absolute lifetime restrictions, I generally recommend limiting repetitive lifting to approximately 25-30 pounds to maximize implant longevity.

Potential Complications

Reverse shoulder arthroplasty is an extremely successful operation, but potential complications include acromial or scapular fracture, implant loosening, instability or dislocation, stiffness, and infection. The complication I encounter most commonly following reverse shoulder arthroplasty is an acromial or scapular fracture. The reverse shoulder changes the mechanics of the shoulder and places increased stress on the surrounding bone. Patients with poorer bone quality are therefore at greater risk, particularly smaller, older women. This is why I am much more protective of these patients during the early postoperative period.

Infection is fortunately uncommon but can be the most devastating complication following shoulder arthroplasty. These infections typically occur months or even years after the operation and are not a direct result of the surgery itself. Instead, bacteria circulating in the bloodstream can attach to the prosthesis and establish an infection around the implant. Treatment requires surgery and usually involves removal of the prosthesis, IV antibiotics, and eventual revision shoulder arthroplasty. Fortunately, complications are uncommon, and the overwhelming majority of patients experience significant improvement in pain, function, and quality of life.