Do lateralization and distalization after reverse total shoulder have a clinically significant relationship with patient outcome?

There are a host of variables that may affect the clinical outcome of reverse total shoulder arthroplasty. A number of authors have attempted to relate distalization and lateralization to outcome scores. For example in Managing rotator cuff tear arthropathy: a role for cuff tear arthropathy hemiarthroplasty as well as reverse total shoulder arthroplasty, the authors found that the postoperative position of the center of rotation and greater tuberosity on anteroposterior radiographs did not correlate with the clinical outcomes for either procedure.

The authors of How To Choose The Best Lateralization And Distalization Of The Reverse Shoulder Arthroplasty To Optimize The Clinical Outcome In Cuff Tear Arthropathy investigated the effect on the 1 year ASES score of combinations of lateralization and distalization of 62 patients having reverse total shoulder arthroplasty performed for cuff tear arthropathy. They measured lateralization by the LSA as shown below





and distalization by the DSA as shown below.







They found the correlation between ASES score and LSA to be = -0.43 and the correlation between ASES score and DSA to be 0.39; both values lying in the "moderate" range.


The accepted value for minimal clinically important difference for the ASES score in total shoulder arthroplasty is 20.9


The DSA of patients with ASES scores > 76 was 48.55 while the DSA of patients with ASES scores < 76. was 37.82, a difference of 10.7.


The LSA of patients with ASES > 76 was 86.43 while the LSA of patients with ASES scores <76 was 100.09, a difference of 13.7.


Thus neither measurement exceeded the threshold for clinical significance.


The authors suggest that optimal LSA should be no more than 90.5° yet of the 24 patients with LSA > 90.5 degrees 75% had ASES scores >76. Furthermore, what should be the lower limit of the LSA?







The authors also suggest that the optimal DSA should be no less than 37.5°, yet of the 17 with DSA less than 37.5, 65% had ASES scores >76. Furthermore, what should be the upper limit of the DSA?




Comment: This is a well done study that effectively uses scatter plots to show all their data. This type of presentation lends itself to an understanding of the variability in the studied relationships.


As the authors point out in their discussion, prior authors have come to varying conclusion about the clinical (rather than statistical) significance of the relationships between distalization angles and lateralization angles.


It seems curious that distalization (a linear dimension) is being measured as an angle, rather than as a linear dimension (see yellow line) and






that laterialization (a linear dimension) is being measured as an angle, rather than as a linear dimension (see yellow line).




Both lateralization and distalization affect deltoid tension, moment arms, center of rotation, stretch on the brachial plexus, the stabilizing compressive force across the articulation, the function of the remaining cuff muscles, the ability to repair the subscapularis and more. We need to know what is the "sweet spot" when the effects of these two variables are considered together?

Finally, distalization and lateralization do not reflect other clinically important variables, such as glenoid tilt, baseplate seating, baseplate fixation, as well as baseplate-bone contact. To determine the relationship of ASES score to the geometry of the reverse total shoulder arthroplasty, a multivariable analysis would be required.

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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).

The value of shoulder outcome scores - what does the patient care about?

Authors often evaluate outcome scores in terms of what statisticians care about, but rarely in terms of what is of interest to the patient. For example, some scores give a substantial weight to range of motion, yet as is shown in this link and by the authors of Relationship Between Patient-Reported Assessment of Shoulder Function and Objective Range-of-Motion Measurements, range of motion is only loosely associated with patient comfort and function. It would seem that patients are most interested in what the shoulder does or does not allow them to do.

Two recent articles by the same author prompted reflection on how one might make an outcome score meaningful to the patient.

In the first, The American Shoulder and Elbow Surgeons score highly correlates with the Simple Shoulder Test the author found that in 1810 simultaneous measurements (both rotator cuff repair and total shoulder arthroplasty) the correlation of the scores was excellent for the ASES and SST for all patients (n . 1810; r . 0.81; P < .0001). The correlation of preoperative scores was strong-moderate (n . 1191; r . 0.60; P < .0001), and the correlation of postoperative scores was excellent (n . 619; r . 0.78; P < .0001). 

In Can the Single Assessment Numeric Evaluation (SANE) be used as a stand-alone outcome instrument in patients undergoing total shoulder arthroplasty? the author found that  correlation was excellent for the SANE score and the ASES score (n . 1447, r . 0.82, P <.0001), WOOS score (n . 1514, r . 0.83, P <.0001), and SST score (n . 1095, r . 0.81, P <.0001). The correlation of preoperative scores was moderate and that of postoperative scores was strong-moderate when the SANE score was compared with all 3 other scores. All scores were highly responsive. Interestingly, 39% of the patients did not answer all of the ASES questions.

While the author concluded that " The SANE score may provide the same information as the WOOS, ASES, and SST score regarding outcomes with a significant reduction in responder burden, " this is not actually the case. The SANE, the WOOS, the ASES, the PROMIS, the UCLA, and the Constant score each reduce the patient's comfort and function to a single number using a formula that weights the different components without regard to the priorities of the individual patient.  The question is whether such a single number is of value to the patient, e.g. "after your surgery your "score" is likely to improve from 37 to 63".  

By contrast, the Simple Shoulder Test is a highly patient-accessible measure that takes but a minute to compete by patients whether they are at home or in the office, is free from observer bias, requires no scoring or computer, and yields data on 12 individual functions without attaching a weight to them:

Thus it is easy for prospective patients to see which functions are likely to be improved after surgery as shown below for the reverse total shoulder and which allows the prospective patient to decide which functions are of highest priority (e.g. sleeping comfortably may be of prime importance to one patient, while the ability to lift a pound to shoulder level may be of highest priority to another).

Such data are likely to be surgeon-dependent; thus surgeons who collect their own data can use them to inform prospective patients that "in my personal experience only two out of ten patients with a condition similar to yours are able to sleep comfortably before a reverse total shoulder while after surgery seven out of ten regain this ability; only one in ten are able to lift a pound to shoulder level before surgery while seven out of ten can do this after surgery". 

This type of presentation informs the patient that (1) the surgeon cares about their personal outcomes enough to collect and analyze their own data and (2) while surgery helps most individuals, there are patients who do not regain full functionality. Surgeon-specific data of this type can be an important part of the preoperative discussion and informed consent. 

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

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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).

Rotator cuff repair - 15 year clinical outcomes - can they be improved upon?

Long-term followup of shoulder procedures is of great interest to patients and surgeons. Rotator cuff repair (RCR) is perhaps the commonest of shoulder surgeries, therefore extended followup is also of great interest to the payers of health care. Yet getting reliable and relevant data is difficult because of patients lost to followup and evolution of surgical techniques.

The authors of  Minimum 15-year follow-up for clinical outcomes of arthroscopic rotator cuff repair point out that while studies have shown considerable symptomatic relief in the short term following surgery, a relatively high rate of recurrent defects has led surgeons to question the long-term durability of this operation. 

193 patients had all-arthroscopic rotator cuff repair by one of 12 surgeons between 2003 and 2005 and thus were potentially eligible for 15 year followup. Rotator cuff integrity was classified according to the method described by Harryman et al (Repairs of the rotator cuff. Correlation of functional results with integrity of the cuff). In this classification scheme, type 0 indicates intact; type 1A, partial tear of the supraspinatus; type 1B, full-thickness tear of the supraspinatus; type 2, full-thickness tear involving the supraspinatus and infraspinatus; and type 3, full thickness tear involving the supraspinatus, infraspinatus, and subscapularis. 

They collected patient-reported outcomes preoperatively and at 1, 2, 5, and 15 years postoperatively.  60 patients (31% of the initial cohort) had a mean follow-up period of 16.5 years. For these patients, the mean ASES score improved from 60 preoperatively to 93 at 15 years. 

There were no factors significantly associated with the final ASES score. Specifically neither the tear size or the integrity of the repair at 5 years correlated with the final ASES score.

Comment: While a 31% fifteen year followup rate is impressive, the lack of data on the missing 69% leaves us without a full understanding of the long term effectiveness of RCR. The lack of correlation of the available outcomes with the integrity of the repair leaves us without information regarding the importance of a durable repair. 

Substantial resources are being poured into innovations for improving the healing rates and clinical outcomes of cuff repair, such as different repair methods (double row, transosseous equivalent, etc), grafts, stem cells, platelet rich plasma, and growth factors. This study shows that accessing the longterm value of these efforts to the patient will be difficult.  

Furthermore, the ASES score for the patients in this study with 15+ years of followup averaged 93. According to Establishing minimal clinically important difference for the UCLA and ASES scores after rotator cuff repair The mean MCID value for the ASES score was 15.2 points. Thus, since the maximum ASES score is 100, it is not mathematically possible for any innovation to make a clinically significant improvement in the outcome of rotator cuff repair.

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: https://twitter.com/shoulderarth

Follow on facebook: click on this link

Follow on facebook: https://www.facebook.com/frederick.matsen

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).

What is the effect of socioeconomic status on patients with glenohumeral osteoarthritis?

 Lower Socioeconomic Status Is Associated With Worse Preoperative Function, Pain, and Increased Opioid Use in Patients With Primary Glenohumeral Osteoarthritis

These authors sought to characterize the role of socioeconomic status (SES) in 982 patients undergoing primary anatomic total shoulder arthroplasty (TSA) for primary glenohumeral osteoarthritis (OA).

They assessed patient demographics, comorbidities, patient-reported outcome scores, range of motion, and preoperative opioid use. Each patient was assigned to a quartile according to the Area Deprivation Index (ADI) using their home address (see this link).

The map for Texas shows a huge variation in the ADI, ranging from most disadvantaged 
(dark red) to least disadvantaged (blue).

They found that the most disadvantaged patients (lower SES) had 

a higher body mass index

higher rates of preoperative opioid use 

higher rates of diabetes.

more preoperative pain (Constant—Pain and American Shoulder and Elbow Surgeons [ASES]—Pain) and

lower function (Constant—ADL, Constant—Total, and ASES). 

Multivariate regression identified that male patients and advanced age at surgery had better reported ASES pain scores, while preoperative opioid use, chronic back pain, and the most disadvantaged quartile were associated with worse ASES pain scores.

Comment: This study provides a means for stratifying an important characteristic of patients having shoulder arthroplasty: their socioeconomic status. The authors suggest that the area deprivation index is a better measure of socioeconomic status than insurance status alone because its methodology accounts for factors such as income/poverty, education, employment, housing, and occupation.

A notable finding of this study is that SES was directly correlated with the preoperative patient assessed comfort and function as shown below

This is important because preoperative ASES score is recognized as a strong predictor of the postoperative ASES score.

This study suggests that patients who are identified as socioeconomically disadvantaged are likely to benefit from preoperative attention to their overall health, nutrition, pain management and home support systems.

Follow on twitter: https://twitter.com/shoulderarth

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How you can support research in shoulder surgery Click on this link.

Here are some videos that are of shoulder interest

Shoulder arthritis - what you need to know (see this link)

Shoulder arthritis - x-ray appearance (see this link)

The smooth and move for irreparable cuff tears (see this link)

The total shoulder arthroplasty (see this link).

The ream and run technique is shown in this link.

The cuff tear arthropathy arthroplasty (see this link).

The reverse total shoulder arthroplasty (see this link).

Can patients accurately remember their pre-arthroplasty shoulder pain - impact on MCID calculation?

 Patients recall worse preoperative pain after shoulder arthroplasty than originally reported: a study of recall accuracy using the American Shoulder and Elbow Surgeons score

The benefit of shoulder arthroplasty is measured by the preoperative to postoperative change in shoulder comfort and function as perceived by the patient. When preoperative scores are not obtained, it is tempting to try to "retrieve" the preoperative state of the shoulder from the patient's memory. 

These authors investigated the accuracy of patient recall in determining the preoperative American Shoulder and Elbow Surgeons (ASES) score for patients having total shoulder arthroplasty (TSA). They compared actual ASES scores determined prior to surgery with ASES scores based on patient recall at  at 6 weeks, 3 months, 6 months, and 12 months after surgery.

They divided the ASES score into two subcomponents: functional ability and visual analog scale (VAS) for pain.

While recalled ASES function scores were comparable to corresponding preoperative scores across

all time points (analysis of variance, P = .21), recalled VAS pain was significantly higher at all time

points beyond 6 weeks after surgery.

As a result, the recalled preoperative total ASES score was worse than the measured preoperative score.

This indicates that the benefit of shoulder arthroplasty (preoperative to postoperative change) based on recall of the preoperative condition of the shoulder is likely to be exaggerated. Therefore, measurement of the benefit of shoulder arthroplasty needs to be based on the actual, rather than the recalled preoperative comfort and function of the shoulder.

Comment: The results of this study also create uncertainty about the commonly used "anchor method" for determining the minimal clinically important difference (MCID).  The "anchor"is often a questionnaire that asks patients to rate retrospectively the improvement in their shoulder after shoulder arthroplasty. For example, a 4-point anchor might ask patients to rate the change in pain after surgery as “worse,” “no different,” “improved,” or “much improved.” The MCID for the ASES score would be the difference in the average ASES scores of patients answering “worse” or “no change” and the average ASES scores of  patients who answered “improved.” Because this study found that patients inaccurately recalled their preoperative pain, their ability to rate the amount of change in pain may also be inaccurate. Specifically, if patients recall more pain than they actually had, some patients may rate their shoulder as "improved" whereas the actual change in pain was "unimproved". 

Follow on twitter: https://twitter.com/shoulderarth

Follow on facebook: https://www.facebook.com/frederick.matsen

Follow on LinkedIn: https://www.linkedin.com/in/rick-matsen-88b1a8133/

How you can support research in shoulder surgery Click on this link.

Here are some videos that are of shoulder interest

Shoulder arthritis - what you need to know (see this link)

Shoulder arthritis - x-ray appearance (see this link)

The smooth and move for irreparable cuff tears (see this link)

The total shoulder arthroplasty (see this link).

The ream and run technique is shown in this link.

The cuff tear arthropathy arthroplasty (see this link).

The reverse total shoulder arthroplasty (see this link).

Are arthroplasty outcomes improving and, if so, why might that be?

 Outcomes of shoulder arthroplasty by year of index procedure: are we getting better?

These authors performed a retrospective analysis of 1899 patient-reported outcomes from their institution’s registry between 2008 and 2018 for anatomic (aTSA) and reverse (RTSA) shoulder arthroplasty. Of 2952 patients entered into the registry, 2 and/or 5 year followup data were available in 1899 (64%); over one-third of the patients did not have followup data.

The average preoperative to postoperative improvement in ASES score for patients reporting two-year followup did not change over time for either aTSA or RTSA

The average preoperative to postoperative improvement in ASES score for patients reporting five-year followup was higher for more recently performed surgeries.

Note in both of the graphs above that the improvement in ASES scores was consistently greater for aTSA than for the more expensive RTSA. Thus the value (benefit/cost) was greater for aTSA.

ASES scores were associated with patient sex, American Society of Anesthesiologists classification, rotator cuff status, primary diagnosis, Walch classification, and revision procedures. Specifically included patients from more recent surgeries were more likely to have a diagnosis of primary osteoarthritis. This was particularly the case for patients having rTSA.

Over the duration of this study there were decreases in the rates of aTSA patients having rheumatoid arthritis, avascular necrosis, cuff tear arthropathy, torn rotator cuff or‘‘other’’ diagnoses relative to OA over time. 

There were decreases in the rates of RTSA patients with acute fracture, old trauma, cuff tear arthropathy, instability, infection, and ‘‘other’’ diagnoses.

Therefore for both procedures, the percentage of the straightforward diagnosis increased while that of the more complex diagnoses decreased.

Comment: Interestingly the 50 point improvement in ASES scores for the most recently performed anatomic shoulder arthroplasties in this study was similar to the improvement reported in a recent publication Assessing the Value to the Patient of New Technologies in Anatomic Total Shoulder Arthroplasty across 20 years:

In that publication, the reported amount improvement in ASES scores after aTSA did not change over two decades (see chart above). 

The results of Outcomes of shoulder arthroplasty by year of index procedure: are we getting better?suggest that the improved results these surgeons observed for more recently performed surgeries may be attributed in large part to a shift in indications for shoulder arthroplasty away from more complex diagnoses in favor of the more straightforward diagnosis of osteoarthritis.

This paper did not assess the value of new implants or technologies, such as preoperative 3D CT planning, in improving the outcome of shoulder arthroplasty. In their discussion they point out that patients receiving newer implant designs do not always achieve better clinical outcomes (see Is there evidence that the outcomes of primary anatomic and reverse shoulder arthroplasty are getting better?) In "Does an increase in modularity improve the outcomes of total shoulder replacement? Comparison across design generations." the authors examined three different generations of implants for total shoulder arthroplasty, determining that second and third generations of glenoid components were at a higher risk of failure when compared with first generation implants.

Since the date of surgery is usually not a modifiable predictor of the result of shoulder arthroplasty, we need to continue to evaluate the importance of procedure selection and surgical technique in optimizing arthroplasty outcomes for patients with different diagnoses and personal characteristics. 

Follow on twitter: https://twitter.com/shoulderarth

Follow on facebook: https://www.facebook.com/frederick.matsen

Follow on LinkedIn: https://www.linkedin.com/in/rick-matsen-88b1a8133/

How you can support research in shoulder surgery Click on this link.

Here are some videos that are of shoulder interest

Shoulder arthritis - what you need to know (see this link)

Shoulder arthritis - x-ray appearance (see this link)

The smooth and move for irreparable cuff tears (see this link)

The total shoulder arthroplasty (see this link).

The ream and run technique is shown in this link.

The cuff tear arthropathy arthroplasty (see this link).

The reverse total shoulder arthroplasty (see this link).