Reverse Total Shoulder Replacement

What is a "reverse" shoulder replacement?

In a reverse joint replacement we change the normal anatomical structure of the shoulder. The shoulder is a ball-and-socket type joint: on one side there is a round structure, the head of the humerus, and on the other a concave structure, the glenoid. When a reverse shoulder implant is inserted, the ball-shaped surface is attached to the glenoid, while the concave surface is attached to the head of the humerus.

Who is the operation intended for?

The operation is intended for patients with a massive rotator cuff tear that cannot be repaired. It is usually performed in older people above age 70. Where previous operations to repair the tears have failed, the operation may also be performed at a younger age. Another situation that calls for a reverse shoulder replacement is severe cartilage wear. In this situation we would in principle prefer a standard replacement (see the article on joint replacement for arthritis), but if the patient is older, or a tendon tear is also known, or there is marked bone deformity as a result of the wear, then I prefer a reverse replacement.

What is the advantage of a reverse shoulder over a standard anatomical implant?

A standard implant is intended to replace only the worn cartilage surface of the joint, in cases of cartilage wear. The condition for a standard implant to succeed is normal function and integrity of the rotator cuff tendons and muscles.

A reverse shoulder joint removes the need for the rotator cuff muscles to work properly, and allows the shoulder to function even without these muscles, or at least with some of them missing.

A reverse shoulder implant is also more stable, so if there is instability of the joint combined with cartilage wear, the reverse shoulder implant will also solve the instability.

What is the disadvantage of a reverse shoulder?

The main disadvantage is the relative restriction of movement that results from the design of the implant. Restriction is expected mainly in movements with the hand behind the back, but there may also be difficulty with external rotation, for example when reaching behind the head.

A second disadvantage of the reverse shoulder comes from the change in the structure of the shoulder, which creates a slight deformity. The typical appearance is that the shoulder looks "drooping": the round contour of the shoulder disappears and a small step appears in its place.

Who is reverse shoulder replacement surgery intended for?

The operation is intended for patients who suffer from severe limitation of shoulder function, to the point of being unable to raise the arm, as a result of a large rotator cuff tear that cannot be repaired.

Another group of patients is those with severe wear of the joint surfaces at an older age (above 75), with bone deformity and a tendon condition that does not allow a standard (anatomical) joint replacement.

A third group is older patients above age 75 with complex shoulder fractures, where the assessment is that the tissue quality is not good enough for a repair or for a replacement with a partial implant.

A final group is patients who previously had a replacement with a standard (anatomical) implant that failed; the revision is then done with a reverse shoulder implant.

Of course, there will be individual cases in which the surgeon considers a replacement with the reverse implant according to the condition of the shoulder.

The operation is usually performed in patients above age 65, but in certain cases it can also be considered at a younger age.

What is done in the operation?

During the operation the joint surfaces are replaced. The implant reverses the anatomy of the shoulder, so that instead of the "ball" of the head of the humerus there is a socket, and instead of the socket of the glenoid there is a "hemisphere".

How does the operation work?

In normal shoulder function, the deltoid muscle lifts the arm upwards. The direction of pull is straight up; for the joint to rotate rather than jam against the shoulder blade, the rotator cuff muscles need to hold the head of the humerus in place and allow it to rotate. When the tendons do not function, the shoulder is pulled upwards but the arm does not rise.

A reverse shoulder implant changes the structure of the joint so that the ball is on the shoulder blade and the humerus has a socket that rests on that ball. When the deltoid muscle pulls upwards, the implant, by its very design, resists upward movement of the humerus and therefore allows the deltoid muscle to lift the arm almost fully.

How is the operation performed?

The operation is performed under general anesthesia as an open operation. An incision about 8 cm long is made at the front or the side of the shoulder.

The head of the humerus is cut, and then the glenoid is shaved. A hemispherical metal implant is fixed against the glenoid, and a metal implant with a plastic tray is placed in the humerus. At the top of the humeral implant there is a plastic tray (a material called polyethylene), which allows the humerus to glide against the ball on the glenoid. After the implant is inserted, the incision is closed.

What happens after the operation?

In the first stage, for 3 weeks, the arm is immobilized in a sling and only pendulum movements are done.

Physiotherapy begins at the end of 3 weeks.

About 3 months after surgery there is usually reasonable daily function, even better than before the operation.

From this stage onwards function improves gradually, and the improvement continues beyond a year after surgery. The reason for the continued improvement is that the body gradually gets used to the change in the structure of the shoulder.

Risks and complications

As with any operation performed under general anesthesia, there are risks related to the anesthesia. Consult your treating physician and weigh the degree of risk in light of any chronic illnesses (heart disease, high blood pressure, diabetes, etc.).

During the operation, depending on the surgical approach, the surgeon works close to nerves and there is a risk of nerve injury. When the technique is performed correctly, the chance of injury is slight.

As with any operation, there is a risk of infection following the procedure. The risk of infection is low – less than 5%.

With joint replacement there is a late risk of dislocation of the joint or loosening of the implants.

Deltoid strengthening protocol after reverse shoulder replacement – step-by-step exercises for the muscle that moves the reverse shoulder.

Explanatory video

Reverse shoulder replacement – indications and the operation – A full explanation of reverse shoulder replacement: who the operation suits, treatment of severe cartilage wear and massive tendon tears, and what to expect during recovery. The video is in Hebrew.