Shoulder Replacement

Reverse shoulder arthroplasty (RSA) and anatomic shoulder arthroplasty (ASA) are surgical procedures used to treat conditions that cause severe shoulder pain and disability. The choice between the two typically depends on the specific condition of the patient’s shoulder, the patient’s overall health, and the expected outcomes of the procedure.

Reverse Shoulder Arthroplasty (RSA):

RSA is called “reverse” because it reverses the anatomy of the shoulder. The ball and socket parts of the shoulder joint are swapped. This procedure is indicated in cases where the traditional shoulder replacement may not work well due to the underlying conditions, such as:

• Rotator Cuff Tears: RSA is often indicated in patients with large rotator cuff tears that are irreparable and lead to a complex condition known as cuff tear arthropathy.
• Severe Fractures: RSA can also be used in elderly patients with severe fractures of the proximal humerus, particularly when the fractures affect the shoulder joint or when previous treatments have failed.
• Previous Surgery Failure: If a previous shoulder replacement surgery has failed, especially due to rotator cuff failure or instability, RSA might be chosen.
• Severe Arthritis with Intact Rotator Cuff: RSA can be used in patients with severe arthritis and an intact rotator cuff, although this is less common.

Anatomic Shoulder Arthroplasty (ASA):

ASA replicates the natural anatomy of the shoulder, replacing the arthritic humeral head with a prosthetic metal ball and the glenoid with a plastic socket. This procedure is often indicated for:

1. Osteoarthritis: This is a common indication when the patient has intact rotator cuff tendons.
2. Rheumatoid Arthritis: ASA can also be used in patients with rheumatoid arthritis, again when the rotator cuff tendons are intact.
3. Post-traumatic Arthritis: In younger patients who have developed arthritis following a shoulder injury, an ASA may be performed if the rotator cuff is healthy.
4. Avascular Necrosis: This condition occurs when the blood supply to the humeral head is disrupted, leading to the death of bone cells. If the rotator cuff is still intact, ASA could be an option.

In terms of outcomes, both procedures can provide significant pain relief and improve function. However, RSA typically allows for greater range of motion in the presence of a deficient or torn rotator cuff compared to ASA. On the other hand, when the rotator cuff is intact and the primary issue is joint surface degradation due to arthritis or similar conditions, ASA can provide more natural movement and allows for easier revision surgeon if the implant fails over many years.  In a recent study published in the Journal of Shoulder and Elbow Surgery 2021 by Flurin, et al., compared reverse shoulder arthroplasty versus anatomic shoulder arthroplasty.  At follow-up, anatomic total shoulder arthroplasty demonstrated greater overhead range of motion and external rotation. All patient-reported outcomes remained similar between the two groups. Reverse shoulder arthroplasty patients were more likely to rate shoulders as much better or better after surgery (90% versus 67%, p = 0.004). Complications were observed in 24% of anatomic total shoulder arthroplasties and 8% of reverse shoulder arthroplasties (p = 0.02). Reoperation was more common in anatomic total shoulder arthroplasties (23% versus 4%, p = 0.003).  Currently, still a strong indication for anatomic shoulder arthroplasty, would be a young person undergoing shoulder replacement allowing for easier revision surgery to reverse if needed.  In older patients where revision surgery is not necessarily needed a reverse shoulder should be strongly considered.  

It should also be noted that the outcome of these surgeries can also depend on the specific surgical techniques used, the prosthetics used, and the patient’s rehabilitation and physical therapy following surgery.  At Total Orthopedics and Sports Medicine we have a full team of surgeons and therapists who can assist you in optimizing your surgery and recovery.