Shoulder replacements have become more common in recent years. There are two primary types of shoulder replacements used in a surgical setting:

• Anatomical total shoulder arthroplasty (TSA)

• Reverse total shoulder arthroplasty (rTSA)

While both surgeries replace natural components of the shoulder joint (glenohumeral joint) with artificial parts, there are distinct differences between the two procedures. This includes the reason behind why one specific surgery is chosen over the other, the anatomical differences between each surgery, and the post-operative recovery and rehabilitation.

The chosen research article dives into explaining the main differences between a TSA and rTSA, as well as performs a thorough review and comparison amongst other available research to see how the post-operative rehabilitation protocols compare.

Let’s see what they found out!

The Main Differences Between a TSA and rTSA

This article does an excellent job in defining the primary differences between a TSA and rTSA.

First of all, the anatomical differences between the two procedures. A standard TSA involves replacing the humeral head (ball portion at the top of the upper arm) and the glenoid (socket portion of the shoulder blade, which the humeral head fits into). The prosthetic pieces used during this surgery are similar to the above-mentioned anatomy, and are placed in a fashion comparable to the original anatomy of the shoulder joint.

On the other hand, a rTSA literally reverses things. The original ball-and-socket joint is still there, but in opposite locations. The ball is now where the concave glenoid surface was, and the socket is now where the convex humeral head was. Additionally, the deltoid musculature becomes the dominant group to raise the arm overhead post-operatively.

Next, the article considers the why. Why would a TSA be chosen over a rTSA and vice versa? One of the biggest factors for determining a TSA versus a rTSA is the status of the rotator cuff. If a shoulder has severe osteoarthritis, but remains with an intact rotator cuff, then a standard TSA is usually performed. If there is severe osteoarthritis and the rotator cuff is severely damaged, then a rTSA is typically chosen. It can also be a possibility that a rTSA is needed if there is severe rotator cuff damage, but no osteoarthritis present.

For both surgical procedures, some additional diagnoses that may lead to the need for a shoulder replacement could include one or more of the following:

• Avascular necrosis

• Inflammatory arthritis

• Severe arthritis after development of shoulder instability (usually from previous or recurrent shoulder dislocations)

• Severe shoulder fractures

Finally, the article discusses some key differences in how each procedure is commonly rehabilitated. Both surgeries will usually implement the use of a sling for some duration after the procedure (outside of working with your physical or occupational therapist), but how long you use a sling will vary, depending on your surgeon’s preference and protocol.

Each surgery normally will have you begin the rehab process with early range of motion (ROM) with your therapist, but also still making sure to adequately rest and allow early healing at the surgical site. At what point ROM is allowed to be initiated also depends on the surgeon and protocol being followed.

A TSA may allow for certain motions to be initiated that a rTSA does not. For example, a TSA typically avoids the motion of shoulder external rotation beyond a certain point, whereas, a rTSA may more so limit the motion of shoulder internal rotation.

A TSA tends to rely more on the function and quality of the subscapularis muscle (part of the rotator cuff family), therefore, will focus on this more post-operatively than the rTSA will.

Some protocols and overall opinions are of the thought that you can be more aggressive with a rTSA versus an anatomical TSA, and that the amount of initial tissue healing is not as necessary with a rTSA.

Keep in mind, these are a few of the more well-known differences between these two surgeries; however, the issue still remains that there are too many varying opinions and protocols for these procedures.

Methods Used in the Research Article

In an effort to try to find some common ground for the post-operative protocols and rehabilitation from these surgeries, this article went on to explore the available research.

The authors performed what is called a systematic review. They used various search databases to comb through and find available research regarding the post-operative rehabilitation and guidelines for both a TSA and rTSA.

To help narrow their search, they included specific criteria that needed to be met. The criteria included the following:

• The specific procedure of a TSA or rTSA

• An attached rehabilitation protocol

• The research had to be published in a peer-reviewed journal

• Inclusion of describing therapy in the home versus various rehab settings

• Post-operative precautions and protocols based on the anatomy of the procedure performed

• Full access of the information in the English language

Once the best research was able to be identified, the authors read, analyzed and interpreted the information. They used a database to help with the analyzing and interpreting process amongst the various research found.

Further details regarding this process can be found in the article itself.

Results from the Research

After thorough analysis of the available research, the authors of this article found 16 research papers that fit all of their criteria (They actually began with 3317!).

The consensus is that a post-operative protocol is needed for each type of surgery; however, there are many differing opinions with regards to the protocols used after surgery. The evidence they did find with the research is considered low quality though, indicating a need for higher quality research with regards to this topic.

For a TSA, there is a necessary balance between resting the shoulder and early ROM. Additionally, protection of the subscapularis muscle is important to keep in mind. If the subscapularis doesn’t rehab properly after a TSA, this can significantly affect pain and functional use of the shoulder.

Considering the importance of the subscapularis muscle with a TSA, the research did not seem to agree very well regarding how much this muscle should be protected after surgery. Some research seemed to promote a longer healing and resting period for the subscapularis muscle, therefore, recommended limiting active assisted ROM early after surgery, which one would typically practice with equipment, such as pulleys.

There did appear to be an agreement to limit the amount of shoulder external and internal rotation after surgery.

For a rTSA, there were also a lot of varying opinions regarding how long to use a sling after surgery and when to start, as well as how to progress,ROM.

Most agreed that after a rTSA the motions of shoulder internal rotation, extension and adduction should be limited. This is the functional motion we perform when we reach behind our back towards our back pockets. The main concern for this motion is the potential of creating instability and a possible dislocation in the shoulder joint. The only thing that wasn’t clear though was at what point can this motion be introduced after a rTSA.

Take-Home Points

A TSA and rTSA are becoming more and more commonly needed in a surgical setting. Like any joint replacement, the post-operative recovery and rehab process is crucial for success of the surgery.

As of now, while there is plenty of research and literature discussing these procedures and recommended post-operative rehab protocols, the evidence of these studies is considered low and there exists a lot of disagreement regarding how to progress a patient after this type of surgery from a rehab standpoint.

Following a specific rehab protocol that describes how long to keep the shoulder immobilized in a sling, create a balance between rest and early ROM, understand which ROM directions to practice and which to avoid early on, and so on is essential for post-operative success.

There needs to be higher level, quality evidence that can reach more of a consensus regarding what the post-operative rehab progression should be for each type of procedure.

With a greater consensus and higher quality studies, successful results from these surgeries will become an automatic outcome.

Resource:

1.   Bullock GS, Garrigues GE, Ledbetter L, Kennedy J. A Systematic Review of Proposed Rehabilitation Guidelines Following Anatomic and Reverse Shoulder Arthroplasty. Journal of Orthopaedic & Sports Physical Therapy. 2019;49(5):337-346. doi:https://doi.org/10.2519/jospt.2019.8616.