UW Shoulder and Elbow Academy: In comparison to anatomic total shoulder, reverse total shoulder is associated with greater anterior shoulder pain and internal rotation dysfunction in patients with osteoarthritis.

While there is a trend toward increasing use of reverse total shoulder arthroplasty (rTSA) instead of the traditional anatomic total shoulder (aTSA) in the surgical management of glenohumeral arthritis with an intact rotator cuff, the patient outcomes of rTSA can be complicated by anterior shoulder pain (Conjoint tendon release for persistent anterior shoulder pain following reverse total shoulder arthroplasty) and deficits in internal rotator function (Internal rotation limitation is prevalent following modern reverse shoulder arthroplasty and negatively affects patients' subjective rating of the procedure).

The authors of Comparison of anterior shoulder pain and internal rotation dysfunction after anatomic and reverse shoulder arthroplasty for osteoarthritis assessed these two complications at two years in similar patients with arthritis having rTSA or aTSA using an anterior shoulder pain and dysfunction score (ASPDS) and the functional internal rotation (FIR) score [these two questionnaires are shown at the end of this post].

Twenty-six patients were included in each of the aTSA and rTSA groups. Mean ASPDS scores were lower in the rTSA group (p=.001).

Mean FIR score was also worse in the rTSA group compared with the aTSA group (p = .004).

The ASES, SANE, and VAS scores were not signficantly different between the two groups (I believe this is because only 2 out of 100 points of the ASES score are given for internal rotation; the SANE and VAS scores are each a single number without any functional specificity). The Simple Shoulder Test was not used in this study (High and low performers in internal rotation after reverse total shoulder arthroplasty: A biplane fluoroscopic study found that the SST was sensitive to loss of internal rotation function).

In their discussion, the authors state, "In our experience, patients who undergo rTSA more commonly identify anterior shoulder pain and discomfort with tasks requiring forward elevation. rTSA patients scored an average of 3.5 points lower on the ASPDS compared to aTSA. Specifically, these patients reported worse outcomes on the questions about having anterior shoulder pain with activity, reaching out to shake someone’s hand or grab a TV remote, raising their arm to touch their face and hair, lifting a grocery bag to the counter, and pushing open a heavy door." These are substantial disabilities.

Comment: This is an important study in that it showed that patients having reverse total shoulder arthroplasty for arthritis had significantly greater problems with anterior shoulder pain and internal rotation dysfunction than those having anatomic total shoulder arthroplasty.

The authors of another recent study, Extension of the Shoulder is Essential for Functional Internal Rotation After Reverse Total Shoulder Arthroplasty proposed that limitation of reach behind the body after RTSA may not be primarily related to a deficit of glenohumeral internal rotation but rather due to a lack of humerothoracic extension.

From the above I suspect that anterior shoulder pain and loss of functional internal rotation are both due to over-tightening of the coracoid muscles by excessive distalization of the humeral component in reverse total shoulder arthroplasty. Surgeons can examine humerothoracic extension with the trial rTSA components in place. If extension is limited, the surgeon can consider modifying the amount of distalization or release of the short head of the biceps and coracobrachialis from the coracoid.

Keeping in mind that the tension in the coracoid muscles is always increased by reverse total shoulder arthroplasty, surgeons can measure the amount of distalization (and lateralization) on preoperative and postoperative radiographs and use these measurements as part of the evalation of patients who have postoperative anterior shoulder pain and internal rotation functional deficits. In the example below the humerus has been distalized relative to the acromion by 24 mm, from 15.1 mm before surgery to 39.1 mm after surgery.

These potential adverse outcomes merit consideration of the choice of type of arthroplasty (rTSA vs aTSA) for patients with cuff-intact osteoarthritis.

The potential complications of reverse total shoulder are worth a good look

Western Tanager

Matsen backyard

2020

You can support cutting edge shoulder research that is leading to better care for patients with shoulder problems, click on this link

Follow on twitter/X: https://x.com/RickMatsen
Follow on facebook: https://www.facebook.com/shoulder.arthritis
Follow on LinkedIn: https://www.linkedin.com/in/rick-matsen-88b1a8133/

Here are some videos that are of shoulder interest
Shoulder arthritis - what you need to know (see this link).
How to x-ray the shoulder (see this link).
The ream and run procedure (see this link).
The total shoulder arthroplasty (see this link).
The cuff tear arthropathy arthroplasty (see this link).
The reverse total shoulder arthroplasty (see this link).
The smooth and move procedure for irreparable rotator cuff tears (see this link)
Shoulder rehabilitation exercises (see this link).