Spinning the data on the value of glenoid augmentation - a guide for authors of systematic reviews and meta-analyses

In the previous post we discussed the challenges in doing clinically significant research on shoulder arthroplasty.

As a follow-on, here we focus on the importance of the way research is presented, with particular reference to spin – defined as bias that overstates efficacy and/or underestimates harms of a treatment. Systematic reviews and meta-analyses are at risk for spin if there was bias in the primary studies on which they were based. 

There is the potential for spin in any presentation of outcomes. Evaluation of spin in reviews of biodegradable balloon spacers for massive irreparable rotator cuff tears found that 93.1% of the 29 included studies had at least one type of spin. See other examples of spin in our literature on this post. 

A recent article provides a useful guide to the elements of spin and how to avoid them.

The authors of Evaluation of Spin in Systematic Reviews and Meta-Analyses Involving Glenoid Augmentation in Total Shoulder Arthroplasty assessed the quantity and types of spin in systematic reviews and meta-analyses of glenoid augmentation in shoulder arthroplasty. They searched for each of 15 types of spin (see A new classification of spin in systematic reviews and meta-analyses was developed and ranked according to the severity). At least one form of spin was identified in 13 (81.3%) of the 16 studies. 

“The conclusion claims the beneficial effect of the experimental  treatment despite a high risk of bias in primary studies” was the most commonly occurring type of spin in this review; it is found in many previous studies in other orthopaedic literature, ranging from 23.1%-65%. A common weakness contributing to this type spin was drawing conclusions based on primary studies of low levels of evidence

‘‘Conclusion claims the beneficial effect of the experimental treatment despite reporting bias’’ was the next most common; which may mislead readers by the selective inclusion and omission of results in the abstract. Reporting bias results from the tendency to overreport or selectively publish positive results. One example of reporting bias can be seen in a recent article that concluded that the reverse shoulder arthroplasty “provided highly favorable results” but only reported the statistically significant improvement in Constant scores and omitted the lack of statistically significant improvements in VAS, ASES,  SST, and functional range of motion measurements. 

The 15 types of spin are listed here as a heads up for surgeons considering publishing a systematic review. 

The title claims or suggests a beneficial effect of the experimental intervention not supported by the findings 

Authors hide or do not present any conflict of interest 

Selective reporting of or overemphasis on efficacy outcomes or analysis favoring the beneficial effect of the experimental intervention 

Selective reporting of or overemphasis on harm outcomes or analysis favoring the safety of the experimental intervention 

Failure to specify the direction of the effect when it favors the control intervention 

Failure to report a wide confidence interval of estimates 

The conclusion claims the beneficial effect of the experimental treatment despite a high risk of bias in primary studies – Most common 43.8 % of the glenoid augmentation studies.

The conclusion claims the beneficial effect of the experimental treatment despite reporting bias. Second most common (37.5% of the glenoid augmentation studies.).

The conclusion formulates recommendations for clinical practice not supported by the findings 

The conclusion claims safety based on non-statistically significant results with a wide confidence interval 

The conclusion focuses selectively on statistically significant efficacy outcome 

The conclusion claims equivalence or comparable effectiveness for non-statistically significant results with a wide confidence interval 

The conclusion extrapolates the review findings to a different intervention (e.g., claiming efficacy of one specific intervention although the review covered a class of several interventions) 

Conclusion extrapolates the review's findings from a surrogate marker or a specific outcome to the global improvement of the disease 

Conclusion extrapolates the review's findings to a different population or setting 

The authors also applied A Measurement Tool to Assess Systematic Reviews (AMSTAR 2), a questionnaire that quantifies the quality of a systematic  review based on criteria such as whether authors reported presence of bias, impact of bias, the use of a predetermined protocol, funding sources, and conflicts of interest, and/or adequately characterized studies included in the review. Based on this review three (18.8%) of the studies were related as "moderate" quality and the remaining thirteen (81.3%) were rated as "low" quality. None met the criteria for "high" quality.  The elements of the AMSTAR 2 are shown below

Did the research questions and inclusion criteria for the review include the elements of PICO (Patient, Population, or Problem; Intervention; Comparison; Outcome)? 

Did the report of the review contain an explicit statement that the review methods were established before the conduct of the review, and did the report justify any significant deviations from the protocol?
Did the review authors explain their selection of the study designs for inclusion in the review?
Did the review authors use a comprehensive literature search strategy?
Did the review authors perform study selection in duplicate?
Did the review authors perform data extraction in duplicate?
Did the review authors provide a list of excluded studies and justify the exclusions?
Did the review authors describe the included studies in adequate detail?
Did the review authors use a satisfactory technique for assessing the risk of bias in individual studies that were included in the review? 

Did the review authors report on the sources of funding for the studies included in the review?

The authors also found a statistically significant association between the presence of a conflict of interest and the lack of reporting funding sources. These conflicts included examples of all of the following: authors who reported receiving grants, personal fees, royalties, and research fees from orthopedic device manufacturers, as well as authors who were investors, presenters, or consultants for orthopedic device manufacturers.

They concluded  that “Spin is highly prevalent in the abstracts of systematic reviews and meta-analyses studying glenoid augmentation with TSA. Misleading reporting is the most common category of spin.“

 

We want our publications to be as useful and as transparent as possible. Hopefully, this guide will help us avoid spin when we present our work.

Bullock's Oriole

Umtanum Washington, 5/25/25

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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Follow on facebook: https://www.facebook.com/shoulder.arthritis
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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 challenge of measuring shoulder arthroplasty outcomes: bias, ceiling effects, and practicality.

Each surgeon has the opportunity - indeed the responsibility - to keep track of her or his surgical outcomes for the purpose of knowing what is and what is not working in the practice. This point is discussed in detail in this link. In that many failures of arthroplasty occur more than five years after surgery, long-term followup is critical.




Three of the key elements of an effective/informative/practical outcome system are (1) capturing the highest possible percentage of patients treated, (2) being able to present the results to patients in terms that patients and surgeons understand, and (3) having a system that is validated and universally applicable so that data can be compared among centers.

#1 requires minimizing exclusion bias. Many scales, such as the Constant Score, the UCLA score, and the Shoulder Arthroplasty Smart score require the patient to return to the office for the measurement of ranges of motion (and, in some cases, strength). In addition to risking observer bias and inter-observer variability, the requirement of returning to the office risks selectively excluding those patients living at a distance from their provider, those unwilling or unable to return, and those of limited economic means. Computer-based scoring systems, such as the PROMIS and Computer Adaptive Testing, risk selectively excluding patients without access to computers, those who are not computer literate and those not proficient in English. The ideal system makes it easy for all patients to be included in long-term followup: inexpensive, quick to complete, accessible independent of the location of the patient and independent of the patient's computer literacy and access.

#2 requires that the outcome data are presented in a way that is meaningful to the patient and surgeon. Most patients will have difficulty understanding the significance of a "score of 72" on PROMIS, Constant, UCLA or SAS, but many would understand the significance of the improvement in specific shoulder functions achieved by their surgeon for a specific condition presented as shown below (showing results obtained using the Simple Shoulder Test results for extended head hemiarthroplasty in the treatment of patients having cuff tear arthropathy with retained active elevation).





#3 Most of the commonly used outcome measures have been carefully validated, for example see Is the Simple Shoulder Test a valid outcome instrument for shoulder arthroplasty? which shows, in spite of the fact that 15% percent of the patients achieved the maximal SST score, there was a near-perfect correlation between satisfaction and the final SST score, suggesting that the "ceiling effect" is likely to have little clinical significance.





What this means is that a shoulder that can perform each of the 12 SST functions (below) is an excellent and highly satisfactory shoulder.





If the ceiling effect was a concern, one could add a thirteenth question: "Can you throw a football 100 yards with the affected arm?". Very few shoulders, normal or post-arthroplasty, would hit the ceiling of 13/13 "yes" responses.


In the same vein, the authors of Validation of a machine learning–derived clinicalmetric to quantify outcomes after total shoulderarthroplasty and Exactech Equinoxe anatomic versus reverse total shoulder arthroplasty for primary osteoarthritis: case controlled comparisons using the machine learning–derived Shoulder Arthroplasty Smart score correctly point out that the Shoulder Arthroplasty Smart score (you can experiment with it on this link) does not have a ceiling effect. In order to achieve the ceiling of the SAS score, the shoulder needs to be measured as having 180 degrees of active forward elevation, internal rotation to T7, and 90 degrees of active external rotation with the arm at the side.


These values will be difficult to attain because they are substantially greater than those found in the general population (see Shoulder range of movement in the general population: age and gender stratified normative data using a community-based cohort): average active shoulder flexion was 160° and average active external rotation was 59°.

Another approach for those concerned about the "ceiling effect" is put forth by the authors of Quantifying success after anatomic total shoulder arthroplasty: the minimal clinically important percentage of maximal possible improvement. They expressed the amount of improvement as the percentage of maximum possible improvement (%MPI) (based on a prior study: The prognosis for improvement in comfort and function after the ream-and-run arthroplasty for glenohumeral arthritis: an analysis of 176 consecutive cases). The %MPI is calculated as (postoperative score - preoperative score)/(perfect score - preoperative score). The "ceiling" in the %MPI would only be reached if the score improved from the worst possible score to the best possible score - a rare event.
Then they determined the minimal clinically important difference (MCID) for the %MPI using the anchor method. Interestingly their calculated MCID-%MPI values are similar for many of the commonly used scores: 33% for the SST, 32% for the ASES score, 38% for the UCLA score, 30% for the Shoulder Pain and Disability Index score, and 33% for the Shoulder Arthroplasty Smart score.


Comment: A surgeon's choice of the optimal patient followup system needs to be made in consideration of the above factors as well as the required staff time and cost of implementation. The goal is to capture long-term data on the highest percentage of patients treated using a method that is affordable and practical for the office.

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).

Optimizing patient followup after shoulder surgery

As pointed out by E.A.Codman almost a century ago, the goal of outcome research is to follow every patient long enough to determine whether the treatment was successful and to ask, "if not, why not".  The goal of clinical research using patient self-assessment is to capture the largest possible percentage of those potentially eligible, without the risk of non-response or selection bias that may systematically exclude certain categories of patients. Is computer adaptive testing the ideal tool in this regard? 

Let's consider a recent article, Performance and responsiveness to change of PROMIS UE in patients undergoing total shoulder arthroplasty These authors studied the Patient-Reported Outcomes Measurement Information System Upper Extremity Computer Adaptive Test (PROMIS UE CAT) with respect to its responsiveness in patients undergoing shoulder arthroplasty. They found that the PROMIS UE demonstrated excellent correlation (range: 0.68-0.84) with the standard legacy instruments, the Simple Shoulder Test, the American Shoulder and Elbow Surgeons Score and the Oxford Shoulder Score at all postoperative time-points.  

Comment:  The authors pointed out that "the mean number of questions administered by PROMIS UE CAT was 4, compared to 11 in ASES and 12 in both SST and OSS, which translates to a lower patient response burden when filling out PROMIS surveys"; however, it is not at all clear that this "patient response burden" of an extra 34 seconds (see below) compromises the patient participation in postoperative followup. 

Instead, consider "Patients were required to have access to a working email and a computer/phone to participate in this study so socioeconomic factors and advanced age could have limited participation and confound our results." While "all patients undergoing TSA were offered enrollment in this study", only 97 of all the TSAs performed by this busy arthroplasty service between March 2019 and April 2021 could be included. 

Computer adaptive testing requires that the patient have access to and is trained in the use of a computer interface that they will use before surgery and after surgery at the designed followup intervals. While this may be straightforward for some patients, other patients may not have the necessary training and access. 

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It seems important to use a followup system that does not carry the risk of systematically excluding patients who are older, less educated, less healthy or socioeconomically disadvantaged.

For example in a study discussed in this link,  one third of the eligible patients did not provide a 12-month PROMIS response. It appears that the characteristics of the PROMIS system has the potential for excluding a substantial number of patients - possibly those with inferior results or those from less advantaged socio-economic situations (see this link).

For contrast compare the response rate from the above study with that in What is a Successful Outcome Following Reverse Total Shoulder Arthroplasty?, a study in which the more easily accessible Simple Shoulder Test enabled 87% of the patients in the original sample to provide two year followup.  In contrast to the PROMIS, the SST can be completed anywhere and requires only a pencil or a pen.

Another article is relevant: Correlation of PROMIS Physical Function Upper Extremity Computer Adaptive Test with American Shoulder and Elbow Surgeons shoulder assessment form and Simple Shoulder Test in patients with shoulder arthritis 

The purpose of this study was to evaluate the Patient-Reported Outcomes Measurement Informative System Physical Function Upper Extremity Computer Adaptive Test (PROMIS PFUE CAT) measurement tool against the already validated American Shoulder and Elbow Surgeons (ASES) shoulder assessment form and the Simple Shoulder Test (SST) in patients with shoulder arthritis.

The average times to complete the SST and PROMIS PFUE CAT were determined to be 96.9 ± 25.1 seconds and 62.6 ± 22.8 seconds, respectively. The question is whether the saving of 34 seconds is worth the limitations of the PROMIS?

The scatter plot from this article also brings up another issue with the PROMIS: four patients who indicated that they could perform none of the 12 functions of the SST, still had PROMIS scores in the same range as three patients what could perform eight of these functions. Thus, the PROMIS was unable to discriminate between a non-functioning shoulder and a reasonably functional one.

 

Another recent article is relevant:PROMIS Upper Extremity Underperforms Psychometrically Relative to American Shoulder and Elbow Surgeons Score in Patients Undergoing Primary Rotator Cuff Repair

PROMIS UE-CAT correlated to a degree with the ASES (r=0.684) and had a 4% floor effect and no ceiling effect.  While PROMIS UE-CAT initially required fewer test items for overall equivalent coverage of shoulder function assessment, final models after recursive item elimination revealed the ASES instrument to have more well-fitting items over a broader range of shoulder function.

The authors concluded that: "Until further refinements in the PROMIS UE-CAT instrument are made, it should not replace the ASES instrument in patients undergoing primary RCR."

Performance and responsiveness to change of PROMIS UE in patients undergoing total shoulder arthroplasty described the so called "ceiling effect" they observed with the OSS (17%) and the Simple Shoulder Test (18%). How big an issue is this really? In the graph below from The prognosis for improvement in comfort and function after the ream-and-run arthroplasty for glenohumeral arthritis: an analysis of 176 consecutive cases  ...

..it can be seen a large number of patients having the ream and run for osteoarthritis "hit the ceiling" of 12 out of 12 on the SST. This means that 

-the shoulder was comfortable at the side

-the shoulder allowed the patient to sleep comfortably

-the shoulder allowed reach to the small of the back to tuck in a shirt

-the shoulder allowed placement of the hand behind the head with the elbow straight out to the side

-the shoulder could lift a coin, a one pound weight, and an eight pound weight to the level of the top of the head without bending the elbow

-the shoulder allowed carrying 20 pounds at the side

-the shoulder allowed tossing a softball 20 yards underhand

-the shoulder allowed throwing a soft ball 20 yards overhand

-the shoulder allowed washing the back of the opposite shoulder

-the shoulder allowed work full time at the patient's usual job

In our view that's a pretty high ceiling; it is remarkable that so many patients can hit it after the ream and run. Obviously one could avoid the "ceiling effect" by adding a question such as, "would your shoulder allow you to throw 100 yards?", but it seems that "yes" responses to each of the 12 existing questions indicates a comfortable and highly functional shoulder.

Performance and responsiveness to change of PROMIS UE in patients undergoing total shoulder arthroplasty points out that while the minimal clinically important difference (MCID) has been well established for the Simple Shoulder Test (see Is the Simple Shoulder Test a valid outcome instrument for shoulder arthroplasty?) and many of the other legacy scales, but that "further quantification of meaningful responsiveness to change will require estimation of the minimal clinically important difference and substantial clinical benefit for PROMIS UE CAT". 

Finally,  Performance and responsiveness to change of PROMIS UE in patients undergoing total shoulder arthroplasty erroneously states that "all except SST have been translated and adapted to several other languages." See below:

    Simple shoulder test and Oxford Shoulder Score: Persian translation and cross-cultural validation

    Validation of the Simple Shoulder Test in a Portuguese-Brazilian Population. Is the Latent Variable Structure and Validation of the Simple Shoulder Test Stable across Cultures?

    Validation and reliability of a Japanese version of the Simple Shoulder Test: a cross-sectional study

    Validation of the Dutch version of the Simple Shoulder Test

    Validation and reliability of a Spanish version of Simple Shoulder Test (SST-Sp)

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)

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).

Shoulder rehabilitation exercises (see this link).

Total shoulder arthroplasty: what measures are best for quantifying the outcome?

Validation of a machine learning–derived clinical metric to quantify outcomes after total shoulder arthroplasty

These authors propose a new clinical assessment tool constructed using machine learning - the Shoulder Arthroplasty Smart (SAS) score to quantify outcomes following total shoulder arthroplasty (TSA).

They used clinical data from 3667 TSA patients with 8104 postoperative follow-up reports to quantify the psychometric properties of validity, responsiveness, and clinical interpretability for the proposed SAS score.

Three of the six measures of the SAS are determined by the surgeon or surgeon's staff: active flexion, internal rotation, and active external rotation.

And three are patient self-assessed on a 0-10 scale: average daily pain, average pain when lying on the affected side, and ability to use the affected shoulder on a daily basis.

The characteristics of the SAS were compared to those of the Simple Shoulder Test (SST), Constant, American Shoulder and Elbow Surgeons Standardized Shoulder Assessment Form (ASES), University of California Los Angeles (UCLA), and Shoulder Pain and Disability Index (SPADI) scores. 

Convergent construct validity was demonstrated, with all 6 outcome measures being moderately to highly correlated preoperatively and highly correlated postoperatively when quantifying TSA outcomes.

The SAS score was most correlated with the UCLA score and least correlated with the SST. 

While none of the scores exhibited significant floor effects preoperatively or postoperatively or

significant ceiling effects preoperatively.

They noted significant ceiling effects occurred postoperatively for the SST, UCLA, ASES, and SPADI measures, especially for anatomic TSA, men, younger patients, and whites.

The SAS score had the least number of patients with floor and ceiling effects and also exhibited no response bias in any patient characteristic analyzed in this study. 

Patient satisfaction anchor-based thresholds for minimal clinically importance difference and substantial clinical benefit were quantified for all 6 outcome measures; the SAS score thresholds were most similar in magnitude to the Constant score. Regarding responsiveness, all 6 outcome measures detected a large effect, with the UCLA exhibiting the most responsiveness and the SST exhibiting the least. Each of the SAS, ASES, Constant, and SPADI scores had similarly large standardized response mean and effect size responsiveness.

They concluded that 6-item SAS score is an efficient TSA-specific outcome measure with equivalent or better validity, responsiveness, and clinical interpretability as 5 other historical assessment tools. 

Comment: The goals of outcome measurement are to capture the patients' assessment of their comfort and function before and after surgery, to include that highest percentage of patients having the procedure, and to levy the smallest time and cost burden on the patient and the provider. 

Shoulder arthroplasty outcome measures can be divided into two groups: (1) those that are based solely on patient self-assessment (the SST, the ASES and the SPADI) and (2) those that require measurements of range of motion and/or strength by the physician or the physician's staff: the SAS, Constant and the UCLA scores.

The challenges with the second group of metrics include (1) observer bias - the person doing the measurements may be inclined to achieve better results in strength and range after surgery, (2) non-response bias - the fact that the patient needs to return to the office for an in-person examination is likely to eliminate patients from inclusion (see this link), (3) cost - measures of motion and strength require physician or staff time as well as travel expenses for the patient, (4) inter-observer variability - measures of motion and strength may not be consistent among different observers and (5) meaningfulness - measures of motion and strength do not correlate well with patient self-assessment of comfort and function (see reference links below).

 The relationship of shoulder elevation strength to patient-reported outcome after anatomic total shoulder arthroplasty

These authors evaluated the relationship between shoulder elevation strength (SES) and patient reported outcomes (PROMs) after aTSA for the treatment of primary glenohumeral osteoarthritis (GHOA) in a retrospective analysis of 605 patients  having aTSA for primary glenohumeral osteoarthritis. 

SES was tested using a digital dynamometer before and after surgery. The examiners were instructed to have the patient position the arm at 90 of elevation or maximum elevation below the horizontal in the scapular plane and resist the examiner who was holding the dynamometer.

The correlations between SES and the PROMs were very weak before aTSA and weak after aTSA.

The authors concluded that while measurement of SES provides information about shoulder function and outcome related to the treatment of primary GHOA with aTSA, the actual relevance to the patient is unclear as the correlations between SES and PROMs were weak. 

This is an important article, in that it demonstrates that so called "objective" measures, such as shoulder strength, are only weakly associated with patient self-assessed comfort and function. It is also important to recognize that the use of strength and range of motion measures in the assessment of arthroplasty outcomes introduces both observer variability (different examiners are likely to measure strength and range of motion differently) and selection bias (excluding the patients who are unwilling or unable to return to the surgeon's office for followup measurements).  Computer based platforms (PROMIS, OBERD) have similar issues with selection bias by eliminating patients without access to the computer based platform. By contrast, the use of so called "subjective" patient reported metric (PRM) forms that can be completed with a pencil and mailed in to the surgeon enable the inclusion of patients unavailable for in-person followup while keeping the observer (the patient) constant. We must recall that the goal of outcome assessment is to capture the self-assessments of largest percentage of patients for the longest period of time after treatment.

Here is a related article, the key finding of which was that active range of motion correlated poorly with patients' self-assessed function of their osteoarthritic shoulders, meaning that the shoulder function was dependent on characteristics of the shoulder and the patient other than the active range of motion.

 Relationship Between Patient-Reported Assessment of Shoulder Function and Objective Range-of Motion Measurements

In 74 male and 30 female patients with osteoarthritis the authors analyzed the relationship between the SST patient self-assessments of shoulder function  and objective range-of-motion measurements recorded by the observer-independent Kinect motion capture system 

For both female and male patients, they found a poor correlation between objective measurements of active abduction and the total SST scores of osteoarthritic shoulders.

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)

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).

Shoulder rehabilitation exercises (see this link).

Considering new technologies for our practice - understanding bias

 

When should we adopt new technology into our practices?

This is an interesting editorial that considers a surgeon's decision to adapt a new technology. Take our previous post as an example (see link). Noting the high complication rate in that study, is there convincing evidence that we should abandon a standard stemmed humeral implant and use a stemless implant? The finding that the new shoulder arthroplasty system statistically improves patient comfort and function is insufficient, in that virtually all shoulder arthroplasty systems statistically improve patient comfort and function. What is necessary to make the switch is evidence that there is sufficient incremental benefit to the patient over the standard approach to offset the costs of the new technology (see below).

The editorial calls our attention to the risk of bias in papers describing new technologies - factors that may make the new technology appear better than it really is by inflating its apparent benefit and underestimating the harm that may result from its use.

So each of us needs to consider carefully what it would take to move us from what we currently do successfully to some new technology. What problems are we currently having that we are convinced could be solved by a different approach?

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)

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).

Shoulder rehabilitation exercises (see this link).

Follow on twitter: Frederick Matsen (@shoulderarth)

Total shoulder arthroplasty: avoiding the biasing effect of outcome measures

 The relationship of shoulder elevation strength to patient-reported outcome after anatomic total shoulder arthroplasty

These authors evaluated the relationship between shoulder elevation strength (SES) and patient reported outcomes (PROMs) after aTSA for the treatment of primary glenohumeral osteoarthritis (GHOA) in a retrospective analysis of 605 patients  having aTSA for primary glenohumeral osteoarthritis. 

SES was tested using a digital dynamometer before and after surgery. The examiners were instructed to have the patient position the arm at 90 of elevation or maximum elevation below the horizontal in the scapular plane and resist the examiner who was holding the dynamometer.

The correlations between SES and the PROMs were very weak before aTSA and weak after aTSA.

The authors concluded that while measurement of SES provides information about shoulder function and outcome related to the treatment of primary GHOA with aTSA, the actual relevance to the patient is unclear as the correlations between SES and PROMs were weak. 

Comment: This is an important article, in that it demonstrates that so called "objective" measures, such as shoulder strength, are only weakly associated with patient self-assessed comfort and function. It is also important to recognize that the use of strength and range of motion measures in the assessment of arthroplasty outcomes introduces both observer variability (different examiners are likely to measure strength and range of motion differently) and selection bias (excluding the patients who are unwilling or unable to return to the surgeon's office for followup measurements).  Computer based platforms (PROMIS, OBERD) have similar issues with selection bias by eliminating patients without access to the computer based platform. By contrast, the use of so called "subjective" patient reported metric (PRM) forms that can be completed with a pencil and mailed in to the surgeon enable the inclusion of patients unavailable for in-person followup while keeping the observer (the patient) constant. We must recall that the goal of outcome assessment is to capture the self-assessments of largest percentage of patients for the longest period of time after treatment.

Here is a related article, the key finding of which was that active range of motion correlated poorly with patients' self-assessed function of their osteoarthritic shoulders, meaning that the shoulder function was dependent on characteristics of the shoulder and the patient other than the active range of motion.

 Relationship Between Patient-Reported Assessment of Shoulder Function and Objective Range-of Motion Measurements

In 74 male and 30 female patients with osteoarthritis the authors analyzed the relationship between the SST patient self-assessments of shoulder function  and objective range-of-motion measurements recorded by the observer-independent Kinect motion capture system 

For both female and male patients, they found a poor correlation between objective measurements of active abduction and the total SST scores of osteoarthritic shoulders.

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