Shoulder Arthritis / Rotator Cuff Tears / Shoulder Pain

Tuesday, March 21, 2023

Stemless reverse total shoulder - does this innovation solve a problem?

The forces applied to the humeral component of a reverse total shoulder are greater than those applied to the humeral component of an anatomic total shoulder; thus secure humeral fixation is needed. Impaction grafting of standard length reverse humeral stems provides excellent fixation while preserving humeral bone stock. The standard length stem is applicable to all shoulders, including those with osteopenia. As shown below, humeral bone stock is preserved with impaction grafting of the standard stem.

The authors of Stemless reverse shoulder arthroplasty: Clinical and radiological outcomes with minimum two years follow-up indicate that a stemless reverse shoulder arthroplasty design was developed in order to "preserve bone stock".

They sought to present the short term (2 year) clinical and radiological results of this implant, but did not test the hypothesis was that this design would provide better clinical and radiological results compared to stemmed implant or that it was a cost-effective alternative to reverse total shoulder with a standard stem.

Scapular notching was observed 26 in 28 patients (24.3%), humeral loosening in 5 patients (4.3%) and glenoid loosening in 4 patients (3.5%). Eight patients underwent an implant revision.

They found complications in 18 patients (15.7%); one patient had two separate proximal humerus fractures after two falls and one patient had a humeral implant displacement and an acromial fracture after one fall. All complications were:

(0.9%) asymmetric polyethylene,

1 (0.9%) incorrectly positioned humeral baseplate,

2 (1.7%) acromial fractures,

1 (0.9%) case of chronic scapulothoracic conflict,

3 (2.6%) cases of dislocation,

1 (0.9%) case of glenoid ossification,

5 (4.3 %) of humeral implant displacement,

1 (0.9%) case of glenoid and humeral loosening and
5(4.3%) cases of postoperative periprosthetic humerus fracture.

9 (7.8%) patients underwent a re-operation, in 8 (7.0%) cases the implant was revised.

They concluded that surgeons should proceed with caution when using this implant until longer term follow-up data is available.

Comment: From these results, it does not appear that this stemless reverse total shoulder arthroplasty matches the outcomes and safety of a standard stemmed reverse total shoulder. The high rate of problems related to the implant itself, to instability, to loosening of the humeral implant and to humeral periprosthetic fractures is concerning. Furthermore, evidence is lacking that this implant successfully addresses the problems encountered with a standard implant (see this link).

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
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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).

Saturday, March 18, 2023

Shoulder Arthroplasty Planning Technologies

Innovations in shoulder arthroplasty seek to improve clinical outcomes for patients, Three-dimensional computer tomographic (CT) scans provide a more detailed depiction of glenoid pathoanatomy than traditional two-dimensional CT scans or plain films. Preoperative planning software enables the surgeon to visualize different reconstruction strategies. Patient specific instrumentation and computer assisted navigation strive to optimize implant positioning. These technologies can add time and cost to the conduct of shoulder arthroplasty (data on average selling price (ASP) below from Orthopaedic Network News 2023).

Certain questions about these technologies need to be answered by clinical research:

(1) Do these technologies improve the outcomes for patients in terms of improvement in comfort and function along with a reduction in complications and revisions?
(2) If these technologies are of value, in which cases should they be used - what are the "appropriate use criteria" for them?
(3) Are there potential adverse effects associated with the use of the technologies, such as increased rates of infection from prolonged operative time?
(4) Do these planning systems lead to the use of more complex implants (e.g. augmented baseplates for reverses and augmented poly for anatomic glenoid components) that may not be necessary.
(5) Do the different planning technologies results in similar measures, for example of glenoid inclination and version?

(6) How do the results reported by authors with financial conflicts of interest compare to those reported by authors without such conflicts?

Some recent articles bear on these questions:

In 3D preoperative planning for shoulder arthroplasty: an evaluation of different planning software systems it was found that the wide variety of methods used by different companies and institutions results in significantly differing glenoid inclination and version measurements.

In Does commercially available shoulder arthroplasty preoperative planning software agree with surgeon measurements of version, inclination, and subluxation? Preoperative planning software for shoulder arthroplasty had limited agreement in measures of version, inclination, and subluxation measurements.

In The Impact of Preoperative Three- Dimensional Planning and Intraoperative Navigation of Shoulder Arthroplasty on Implant Selection and Operative Time. Using 3D planning increased the likelihood that the surgeon selected an augmented glenoid component compared with 2D planning. Because 3D planning and intraoperative navigation is more costly than 2D planning, and augmented glenoid components are more costly than standard glenoid components, the cost-benefit of these changes with respect to mid- and long-term clinical outcomes and implant survival has not been ascertained.

In Patient-specific Instrumentation Versus Standard Surgical Instruments in Primary Reverse Total Shoulder Arthroplasty: A Retrospective Comparative Clinical Study patients having reverse total shoulder arthroplasty using patient specific instrumentation did not achieve significantly better clinical or radiographic outcomes than those performed without PSI.

As would be expected, authors advocating these technologies are often involved with their development and have financial ties to the companies providing them.Financial support is necessary for the research, development, application, and advocacy of new technologies. In Novel Shoulder Arthroplasty Planning Technologies and Potential Conflicts of Interest most publications on these innovations were found to be authored by those with financial conflicts of interest. Such conflicts can be associated with the results of the studies (Conflict of interest in orthopaedic research. An association between findings and funding in scientific presentations)(Conflict of interest in orthopaedic research)(Demographics of disclosure of conflicts of interest at the 2011 annual meeting of the American Academy of Orthopaedic Surgeons)(Scope and impact of financial conflicts of interest in biomedical research: a systematic review).

Clinical research, including carefully controlled clinical trials, are needed to establish the value of these technologies to the patient having arthroplasty for glenohumeral arthritis.

Wednesday, March 15, 2023

Reverse or anatomic total shoulder for glenohumeral arthritis - does a preoperative MRI help with the decision?

Twenty years ago, the reverse total shoulder arthroplasty (RSA) was approved by the US Food and Drug Administration "in order to restore mobility in a grossly rotator cuff deficient joint with severe arthropathy" (see this link and this link).

Since that time, the use of RSA has expanded rapidly to include "off label" indications, such as primary osteoarthritis with an intact rotator cuff (see Off-label use of reverse total shoulder arthroplasty: the American Academy of Orthopedic Surgeons Shoulder and Elbow Registry).

The application of the RSA for patients having osteoarthritis with an intact cuff can be viewed in the light of several factors:

(1) The current population-based data from the Australian Orthopaedic Association, which shows better long term survivorship for the anatomic total shoulder than for the reverse total shoulder.

(2) The risk of adverse outcomes - some of which are essentially unique to the reverse total shoulder and are difficult or impossible to revise surgically, including baseplate failure, acromial and scapular spine fractures, deltoid fatigue, and limited internal rotation (see My Reverse Has Failed: Top Five Complications and How to Manage Them). Adverse outcomes managed without surgery are not captured by studies that track revision rates.

(3) The greater average selling price for the RSA in comparison to the anatomic total shoulder (the examples below are taken from Orthopaedic Network News 2021)

Because of the foregoing, the decision between anatomic and reverse total shoulder in the treatment of glenohumeral arthritis is of clinical and economic importance.

Being mindful of the original FDA approved indication for RSA - arthritis+cuff deficiency - the authors of Is Advanced Imaging to Assess Rotator Cuff Integrity Before Shoulder Arthroplasty Cost-effective? A Decision Modeling Study pointed out that for some arthritic shoulders, preoperative physical exam, radiographs, and CT scans do not adequately establish the integrity of the rotator cuff. In these shoulders there are two approaches for further elucidating the status of the cuff to inform the decision of RSA vs. anatomic TSA: (1) preoperative cuff tendon imaging (MRI or ultrasound) or (2) intraoperative assessment of the cuff, having both the RSA and anatomic TSA implants available in the operating room.

They conducted a cost-effectiveness modeling study in which all patients having shoulder arthroplasty underwent history and physical examination, radiography, and CT. They compared the cost effectiveness of five strategies (1) no further preoperative cuff imaging, (2) selective MRI, (3) MRI for all, (4) selective ultrasound, and (5) ultrasound for all.

They used a decision model with a base-case 65-year-old patient with a 7% probability of a large-to-massive rotator cuff tear and a follow-up of 5 years. Strategies were compared using the incremental cost effectiveness ratio with a willingness to pay of both USD 50,000 and 100,000 per quality-adjusted life year. Diagnostic test sensitivity and specificity were extracted from published systematic reviews and meta-analyses, and patient utilities were obtained using the Cost-Effectiveness Analysis Registry from the Center for the Evaluation of Value and Risk in Health.

Final patient states were categorized as either inappropriate or appropriate in comparison to the actual rotator cuff integrity and type of arthroplasty performed.

They found that MRI and MRI for all were the most cost effective additional preoperative imaging strategies. However, quality-adjusted life years gained by preoperative soft tissue imaging were minimal: 0.04 quality-adjusted life years gained for MRI for all. The value of additional preoperative imaging increased as the age-related prevalence of cuff tear increased (rotator cuff tear prevalence greater than 12% made MRI for all cost-effective).

A secondary analysis was performed where all patients indicated for TSA underwent intraoperative rotator cuff examination to determine appropriate implant selection. This second analysis was based on the ability of the surgeon to alter the treatment plan using intraoperative rotator cuff evaluation without further preoperative imaging. This strategy was the most cost effective: least costly and achieved the greatest health utility.

They concluded that in the case of diagnostic uncertainty based on physical exam, radiographs, and CT alone, having both TSA and RSA available in the operating room would be more cost-effective than obtaining advanced soft tissue imaging preoperatively.

However, when surgical preparedness, patient expectations, and implant availability compromise the ability to switch implants intraoperatively, performing selective MRI to assess rotator cuff integrity to indicate RSA or TSA is cost-effective

Comment: This is an informative study, providing a clinically useful approach for considering anatomic versus reverse total shoulder for patients with arthritis based on the integrity of the rotator cuff.

A related study would be of great interest as well: comparing the cost effectiveness of anatomic versus reverse total shoulders for the treatment of glenohumeral arthritis in patients with an intact rotator cuff, considering implant cost, complications and revisions.

Thursday, March 9, 2023

The younger patient with shoulder arthritis - things to consider.

It has been noted that anatomic and reverse total shoulder arthroplasties are being used in younger patients (see this link for example).

The authors of Incidence of Primary Anatomic and Reverse Total Shoulder Arthroplasty in Patients Less than 50 Years of Age & High Early Revision Risk sought to investigate the incidence of primary anatomic total shoulder arthroplasty (TSA) and reverse shoulder arthroplasty (RSA), rate of revision within one year, and determine the associated economic burden in patients <50 years.

They found that the incidence of shoulder arthroplasty in patients <50 years old increased from 2.21 to 2.5 per 100,000 patients from 2017-2018.

In these patients the overall revision rate was 3.9% with a mean time to revision of 96.3 days. The one-year revision rate was higher in more recently performed arthroplasties (3.5% for procedures performed in 2017 and 4.4% for procedures performed in 2018).

The revision rates where higher for procedures performed in the Midwest (5.6%) and South (4.4%) than in the Northeast (1.6%) and West (1.4%).

Diabetes and female sex were significant risk factors for revision.

Surgeries performed in patients <40 years cost more than those performed in patients aged 40-50 years for both primary and revision cases.

The one-year revision rate was 3.1% for anatomic TSA and 6.8% for RSA for these patients under 50 years of age. The authors noted that young patients receiving RSA were not only more likely to undergo revision, but were also subject to greater financial, societal, and productivity costs than patients receiving anatomic TSA.

Comment: In this study of one year revision rates, the average time to revision was three months. Things will get worse from that point on. As shown in the chart below from the Australian Orthopaedic Association, the revision rate at three months represents but a fraction of the longer term revision rate.

As pointed out in a prior post, the reported outcomes of shoulder arthroplasty in patients under the age of fifty years are worse than those in patients over fifty. While a number of factors, such as differences in activity level, patient longevity, and differences in expectations, have been proposed as the reason for this difference, the authors of Comparison of Patients Undergoing Primary Shoulder Arthroplasty Before and After the Age of Fifty explored the possibility that patients under fifty years of age had differences in their pre-arthroplasty self-assessed comfort and function, sex distribution, and specific type of arthritis in comparison to their more senior counterparts. Patients under the age of fifty years were not more likely than those over fifty to be female or to have a lower prearthroplasty self-assessed comfort and function score. However, they did have more complex pathological conditions, such as capsulorrhaphy arthropathy (arthritis after surgery for instability), rheumatoid arthritis, and posttraumatic arthritis. Only 21% of the younger patients had primary degenerative joint disease, whereas 66% of the older patients had that diagnosis.

They suggested that the pathoanatomy in these younger patients can complicate the surgery, the rehabilitation and the outcome of the shoulder arthroplasty. The preoperative diagnosis may have at least as much influence on the outcome of the procedure as does the age of the patient.

Recently, the authors of A History of Shoulder Instability is More Common in Young Patients Undergoing Total Shoulder Arthroplasty sought to evaluate whether a history of shoulder instability was more common in patients under 50 years old undergoing TSA. They identified 489 patients undergoing primary TSA within the Military Health System.

Patients under 50 years old were matched 1:2 with patients 50 years and older based on sex, race, and military status; the final study population comprised 240 patients.

The groups differed significantly in type of shoulder arthritis, with the older group having significantly more primary osteoarthritis (78% vs. 51%), while the younger group had significantly more patients with a history of shoulder instability (48% vs. 12%), prior ipsilateral shoulder surgery of any type (74% vs. 34%), and prior ipsilateral shoulder stabilization (31% vs. 5%). In the resultant logistic regression model, a history of shoulder instability (OR 5.0) and a history of any prior ipsilateral shoulder surgery (OR 3.5) were associated with TSA prior to the age of 50 years old.

From the foregoing, it is evident that the shoulder pathoanatomy of young patients having shoulder arthroplasty is different from that of older patients - a fact that may contribute to inferior results in these individuals after shoulder joint replacement. Patient charateristics, such as higher activity levels, higher expectations, and relationships of the shoulder problem to work are also likely to contribute to the increased revision rate.

All of these factors need to be considered in discussions with the patient prior to electing to proceed with shoulder arthroplasty as well as determining the type of arthroplasty to be used.

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).

Tuesday, March 7, 2023

Reverse total shoulder: the importance of inferior angulation of the base plate and how to achieve it.

Inferior inclination of the reverse total shoulder baseplate reduces the risk of component loosening, scapular notching, and limited range of motion.

The authors of The reverse shoulder arthroplasty angle: a new measurement of glenoid inclination for reverse shoulder arthroplasty, point out that the key to achieving inferior inclination is to recognize that (1) the baseplate should be placed on the inferior aspect of the bony glenoid and

(2) the preoperative inclination of the inferior glenoid (C-D) is different than the inclination of the entire glenoid (A-B).

The supraspinatus fossa line is a useful reference line to measure glenoid inclination because the sclerotic line of the supraspinatus fossa line is visible on both plain radiographs and CT scans.

They defined the preoperative reverse shoulder arthroplasty angle as the angle between a line perpendicular to a line drawn along the floor of the supraspinous fossa and the plane of the inferior glenoid (A-S) (below left).

The postoperative reverse shoulder arthroplasty angle is the angle between a line perpendicular to a line drawn along the floor of the supraspinous fossa and the plane of the baseplate (below right).

They suggest that the ideal inclination of the baseplate is perpendicular to the line drawn along the floor of the supraspinous fossa, i.e. the postoperative reverse shoulder arthroplasty angle is zero.

In 47 shoulders with rotator cuff tear arthropathy the preoperartive reverse shoulder arthroplasty angles measured 25±8 degrees on plain radiographs, 20±6 on reformatted 2D CT scans, and 21±5 on 3D reconstructions: thus, each method gave comparable values.

The Favard classification describes the common patterns of glenoid erosion seen with rotator cuff tear arthropathy: no erosion (E0), varying degrees of concentric central erosion (E1), and eccentric superior erosion (E2 and E3). The blue wedges indicate the amount of correction of inclination necessary to place the baseplate perpendicular to a line drawn along the floor of the supraspinous fossa.

Correction of the inclination can be accomplished by reaming the inferior glenoid, adding bone graft beneath the upper part of the baseplate, or using a superiorly augmented baseplate.

Comment: The preoperative reverse shoulder arthroplasty angle is useful for determining the amount of correction needed while the postoperative reverse shoulder arthroplasty angle is useful for determining whether the desired correction was achieved.

Optimizing the mechanics of the reverse total shoulder

There is much discussion of the optimal positioning of the components in reverse total shoulder arthroplasty. The authors of Challenges for Optimization of Reverse Shoulder Arthroplasty Part II: Subacromial Space, Scapular Posture, Moment Arms and Muscle Tensioning provide an in-depth analysis of some of these factors.

Their key findings may be summarized as follows.

(A) In hierachical order, the most important factors for optimizing abduction and adduction range of motion are

(1) lateralizing the gleosphere center of rotation,

(2) distalizing the glenosphere (e.g. by placing the baseplate low, by using a smaller baseplate and/or by using an inferiorly eccentric glenosphere),

(3) inferiorly tilting the glenosphere and

(4) increasing the neck-shaft angle.

The effects of offset and superior/inferior position are represented below where the green zone is the impingement-free range of adduction/abduction.

(B) Patients with severe kyphosis are at risk for reduced adduction, abduction, external rotation and extension. Higher retrotorsion, lower neck-shaft angle and a larger/inferior glenosphere may be considered.

However, a longer lever arm changes the normal length-tension relationships of the muscle (Blix curve). To optimize fiber recruitment and the length of the contractile elements of the deltoid and residual rotator cuff, the authors recommed placing the tuberosity close to the normal anatomic position.

The authors conclusions are:

External rotation, extension and internal rotation are key challenges to the optimization of RSA function. They are substantially improved by the combination of glenoid-sided lateralization, inferior glenosphere overhang, and a decreased neck shaft angle as low as 135 degrees, as outlined in part I of this review.

Lateralization, distalization and inferior glenosphere tilt have been proven to be the three most important factors in hierarchical order to increase glenohumeral ABD by increasing the subacromial space.

Thoracic kyphosis, scapular posture, and motion need to be evaluated, as they may influence planning, positioning, and outcomes of RSA.

Glenoid-sided lateralization (LGMH) and humeral lateralization (MGLH) have different effects on the moment arm but also muscle length for the force generation of RSA.

The total amount of lateralization has been recommended to be close to the anatomical lateralization of the humeral tuberosities; however, the optimal amount of glenoid and humeral contribution is unknown to date.

Monday, March 6, 2023

What determines the outcome or rotator cuff repair; is it the patient's insurance?

While much attention is being focused on the details of the technique of rotator cuff repair (RCR), the characteristics of the patient - rather than the technical details - may play an even more important role in determining the outcome.

The authors of Payor type is associated with increased rates of reoperation and health care utilization after rotator cuff repair: a national database study studied the 90 day incidence of medical complications, emergency department visits, and hospital readmissions, as well as 1-year incidence of revision repair, revision to arthroplasty, and cost of care were evaluated using a large national database. Medicaid patients were matched in a propensity scoring methodology in a ratio of 1:10 to Medicare and commercial patients based on age, sex, and various medical comorbidities including coronary artery disease, uncomplicated diabetes mellitus, obesity, tobacco abuse, chronic pulmonary disease, liver disease, peripheral vascular disease, renal disease, cancer, and congestive heart failure.

It is of interest how unhealthy the patients were overall (see table below): 80% had hypertension, 60% had depression, 50% were obese, 50% had chronic pulmonary disease, 50% had diabetes, over 50% used tobacco, 30% had coronary artery disease. As a group, these patients do not seem to be ideal candidates for elective surgery.

In spite of the matching it can be seen from the table below that the Medicaid population had a higher prevalence for 12 of the comorbidity diagnoses.

While individually the differences in the prevalence of these comorbidities were not statistically significantly different among the three insurance groups, their cumulative prevalence was 30% greater for the Medicaid group than for the Medicare or commercial insurance groups, indicating that as a group they were less healthy before surgery. These things add up.

The authors reported that

1. Medicaid insurance was associated with an increased 90-day risk of various medical complications, emergency department (ED) visits, and 1-year revision RCRs compared with Medicare insurance.

2. Medicaid insurance was also associated with an increased risk of various medical complications, ED visit, and hospital readmission, as well as 1-year risk of revision RCR and conversion to arthroplasty compared with commercially insured patients.

3. Medicaid insurance was associated with higher 1-year cost of care compared with patients with either Medicare or commercial insurance.

Comment: The authors concluded, "This study shows that payor type impacts outcomes after RCR. Patients with Medicaid insurance were more likely to sustain increased medical complications, revision surgery, and increased health care utilization compared with Medicare and commercially insured patients."

This conclusion was reached without controlling for disparities in critical determinants of health: economic, social, environmental, and educational charateristics as discussed in Risk factors for adverse adverse outcomes after shoulder arthroplasty.

In this type of study it is important to avoid a "fundamental attribution error", in other words attributing the effect to type of insurance rather than to differences in medical comorbidities and social determinants of health. A simple test will illustrate: if a patient on Medicaid insurance is scheduled for rotator cuff repair, but the week before suddenly was able to change to commerical insurance, would that change the risk of the adverse outcomes shown in Table III above?

Irrespective of insurance type, complications such as pulmonary embolism, deep venous thrombosis, transfusion, pneumonia, stroke, myocardial infarction, sepsis, acute anemia, renal failure and urinary tract infections occur more often in patients who are overall less healthy, less wealthy, less educated, as well as less supported by family, friends, and primary care providers.

Surgeons can optimize their outcomes for cuff repair by identifying these factors and mitigating the associated risks before proceeding with this elective procedure.

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