Wednesday, February 21, 2024

Short stemmed anatomic total shoulder arthroplasty - the surgeon is the method.

A recent study, Early Radiographic and Clinical Outcomes of Primary Short Stem Anatomic Total Shoulder Arthroplasty with a Peripherally Enhanced Fixation Glenoid: A Multicenter Study, pointed to the importance of surgical technique in performing total shoulder arthroplasty. The authors reviewed the two-year minimum outcomes for 275 consecutive patients having anatomic total shoulder arthroplasty for glenohumeral arthritis performed by one of three highly experienced surgeons. While >50% of the cases showed type B glenoid pathoanatomy, augmented glenoid components were not used. 





These experienced surgeons were usually able to reproduce the desired anatomical relationships, but as seen in the table and in the figures below, there was some variability in surgical technique. 




Postoperative radiographs of 177 cases showed 10 (5.7%) shoulders with glenoid osteolysis; 51 (28.8%) had glenoid radiolucent lines, 


and 81 (45.8%) had calcar resorption. 



Follow-up duration (median 40.1 vs. 27.2 months), BMI (median 27.5 vs. 30.7), and Charleston Comorbidity Index (Q3 0 vs. 1) were associated with glenoid osteolysis in bivariate analyses. 

In multiple logistic regression, surgeon identity (C vs. A/B) was the only statistically significant predictor of glenoid radiolucent lines [OR 0.27, 95% CI (0.1, 0.8)]. Glenoid radiolucent lines were seen respectively in 34.6%, 39.3%, and 10.6% for patients of surgeons A, B, and C .

The authors observed calcar resorption in 46% of cases. Multivariable analysis showed surgeon identity, higher canal filling ratio, over stuffing of the humeral head and glenoid osteolysis to be independent predictors of calcar resorption. By descending importance, Surgeon C [OR 6.5 (2.0, 20.5)], humeral canal filling ratio [upper vs. lower quartile OR 2.3 (1.3, 4.0)], mediolateral humeral head deviation [upper vs. lower quartile OR 1.9 (1.0, 3.5)] and glenoid osteolysis [OR 13.5 (2.6, 71.6)] significantly predicted greater calcar resorption.  Full  thickness calcar resorption was seen in 3.8%, 5.2% and 18.2% of patients of surgeons A, B, and C respectively. 

Effects of the individual surgeons technique are shown in the chart below.



Only longer follow-up duration was statistically associated with two year ASES scores; longer followup was associated with lower scores. 



Comment: The outcomes in this report were excellent and comparable to other reports of modern approaches to anatomic shoulder arthroplasty, including the successful application of non-augmented glenoids to address type B pathoanatomy.

This study demonstrates that even when highly experienced surgeons perform total shoulder arthroplasty, there is inter-surgeon variability in component position as well as in the rates of glenoid lucent lines and calcar resorption.  

The clinical significance of this variability in component position and radiographic outcomes was not demonstrated in the two year ASES scores reported in this study. However, greater deviations from the ideal component positions and longer periods of followup may reveal effects on clinical outcome.

Some surgeons may find greater variability in their component positioning than what is reported here. As discussed in an earlier blog post (Short stemmed humeral components - do they solve old problems or create new ones?), a short stem can be more difficult to center in the humeral medullary canal, especially if the goal is a lower filling ratio.

Some surgeons find it useful to obtain intraoperative fluoroscopy to assure the desired position.


Some surgeons may find the insertion of the glenoid component to be difficult. Excellent glenoid exposure, careful glenoid reaming and accurate drilling of the fixation holes have been shown to be critical to optimal seating of the glenoid component with the goal of minimizing radiolucencies.

The use of preoperative CT based planning was not described in this report. It is not evident that such planning would have addressed the variability described by the authors or improved the clinical outcomes.

You can support cutting edge shoulder research and education that are 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).



Monday, February 19, 2024

Augmented anatomic glenoid components - are they necessary?

Glenoid retroversion is a common feature of arthritic shoulders. 




In performing anatomic total shoulder arthroplasty, some surgeons accept glenoid retroversion, inserting a standard glenoid component combined with techniques to maintain humeral head centering on the glenoid face while others prefer to change glenoid version (see Glenoid version: acceptors and correctors).

The clinical benefit of changing glenoid version for patients with shoulder arthritis is currently being investigated.

Glenoid components with thicker polyethylene posteriorly (see A, B, C and D below) have been used as a means of changing the version of the glenoid articular surface in anatomic total shoulder arthroplasty.



One of the principal factors in anatomic glenoid component loosening is the rocking horse mechanism in which the component lifts off the bony surface in response to eccentric loading.




2013 The authors of Liftoff resistance of augmented glenoid components during cyclic fatigue loading in the posterior-superior direction used an in vitro model to measure the resistance to anterior glenoid liftoff when the posterior glenoid was eccentrically loaded by translating the humeral head 4 mm in the posterior-superior direction. 



Each of the four augmented designs tested were less stable (i.e. showed greater micro motion with loading) than the standard, non-augmented glenoid component. 




These findings may be related to 
(1) the increased liftoff moment arm (blue line segment) resulting from the greater posterior thickness of the polyethylene as emphasized in 2019 Anatomic Augmented Glenoid Implants for the Management of the B2 Glenoid mentioning "concern for stresses generated in augmented implants", "glenoid augments tested in this study are at higher risk for loss of fixation and glenoid loosening because they were less resistant to liftoff", and "the stepped model showed higher levels of shear stress at both radial mismatch settings at the backside of the implant and in the cement mantle. Thus, while both designs performed similarly, the stepped design had high levels of stress, which indicates a higher risk for loosening, and higher amounts of micromotion in high-risk conditions."




and (2) from difficulty in fitting the bone to a complex component backside (below) in contrast to fitting a convex backed component to a spherically reamed bone surface.


The patient outcomes for the different approaches to the retroverted glenoid need to be compared by well-controlled clinical studies (see 2019 Augmented glenoid implants in anatomic total shoulder arthroplasty: review of available implants and current literature)





2015 Preliminary Results of a Posterior Augmented Glenoid Compared to an all Polyethylene Standard Glenoid in Anatomic Total Shoulder Arthroplasty reported on 24 patients with osteoarthritis and posterior glenoid wear who were treated with aTSA using a PAG with a minimum of two-year follow-up matched to patients treated with an all poly non-augmented pegged glenoid (NAG) for osteoarthritis. Sixty per-cent of PAG shoulders had a radiolucent line with an average radiographic line score of 1.10, and 33.3% of NAG had a radiolucent line with an average radiographic line score of 0.438. One glenoid in the PAG group was radiographically but not clinically loose. In the PAG group, 17/20 humeral heads were centered, and three were anteriorly subluxated; none were posteriorly subluxated. There were no differences in any of the measured postoperative clinical outcomes or any difference in improvement between the two groups.

2019 Early results of augmented anatomic glenoid components compared 37 augmented TSAs matched with 37 control shoulders with unaugmented glenoid components. Both augmented and standard TSAs produced similar improvements in all ROM and PRO measures. Patients with augmented glenoid components were more likely to have type B2 or B3 deformities. At final follow-up, 54% of augmented glenoids showed implant lucencies compared with 46% of control shoulders. The mean Lazarus score was similar between groups (1.5 vs. 1.2). The 16° augmentation demonstrated a significantly higher mean Lazarus score (4.2). Reoperation rates were similar between groups (5% vs. 3%).


2021 Stepped Augmented Glenoid Component in Anatomic Total Shoulder Arthroplasty for B2 and B3 Glenoid Pathology reported the use of a stepped augmented glenoid component to correct glenoid version for Walch B2 and B3 glenoids, comparing the radiographic and clinical outcomes at minimum 2-year follow-up with those achieved with a non-augmented component of the same design in Walch A1 glenoids.



Central peg osteolysis was graded as demonstrated below.


Central peg osteolysis with or without glenoid component shift occurred in 29% of B3 glenoids treated with the augmented glenoid component, 10% of B2 glenoids treated with an augmented component and 5% of A1 glenoids treated with a standard component. The clinical outcomes (Penn Shoulder Scores) and complication rates were not different among the three groups. The authors "would not recommend use of this stepped augmented glenoid component for correction of severe B3 glenoid retroversion that requires excessive anterior glenoid reaming".


2022 Early clinical and radiographic outcomes of anatomic total shoulder arthroplasty with a biconvex posterior augmented glenoid for patients with posterior glenoid erosion: minimum 2-year follow-up reported outcomes for three different amounts of posterior augmentation.





Range of motion and patient reported outcomes improved. Version was corrected. No patient had aseptic loosening. Seventy-nine of 86 patients had a Lazarus score of 0 (no radiolucency seen about peg or keel) at final follow-up.

2022 Mid- to long-term outcomes of augmented and nonaugmented anatomic shoulder arthroplasty in Walch B3 glenoids presented 35 patients having a minimum 6 years followup after aTSA. Sixteen patients had an augmented glenoid component, and 19 patients had a standard glenoid component with partial version correction. Standard or augmented glenoid component use was at the discretion of the operating surgeon, based on the amount of posterior bone loss, joint line medialization, and surgeon training/philosophy in management. Preoperative glenoid retroversion averaged 24 degrees in the standard cohort and 29 degrees in those who received augmented glenoid components. The degree of version correction was not presented. There were no statistically significant differences between those with augmented and standard glenoid components for mean ASES score, ASES pain score, SANE score, percentage patient satisfaction, forward elevation, or external rotation. No patient in either group had undergone revision surgery.


2022 Early outcomes of augmented glenoid components in anatomic total shoulder arthroplasty: a systematic review found 9 studies including 312 shoulders underwent anatomic total shoulder arthroplasty using augmented glenoid implants. At an average of 37.1 months the average clinical outcome scores were improved. Glenoid retroversion was reduced from 21 to 9.5 degrees. Radiolucencies were reported in 35% of shoulders. The 16 degree full-wedge augment led to higher and more severe radiographic lucency, while high peg perforation rates (44%) were observed among 5-mm augment stepped implants. The overall rate of complication was 2.6%. Rate of revision surgery was 1.9%. 


2023 Treatment of Glenoid Wear with the Use of Augmented Glenoid Components in Total Shoulder Arthroplasty: A Scoping Review pointed out that while computer modeling and finite element analysis have suggested that excessive glenoid component retroversion is a risk factor for component loosening, there are no scientific guidelines or consensus on the acceptable degree of component retroversion. The authors emphasize the importance preserving glenoid bone stock and of backside contact for the glenoid component on bone to minimize the risk for glenoid failure. In pointing out the additional cost associated with augmented glenoid components, they categorize three primary designs: full wedge, half wedge, and step-cut. Among these they reported greatest amount of glenoid bone removal in stepped implants 


followed by full- wedge, 




with the lowest amount of bone removal in half-wedge components.





The authors of 2023 Factors associated with functional improvement after posteriorly augmented total shoulder arthroplasty observed that posteriorly augmented glenoid components in anatomic total shoulder arthroplasty (TSA) address posterior glenoid bone loss with inconsistent results. They presented a retrospective review of 50 patients having TSA with a step-type augmented glenoid component at a minimum of 2 years after surgery. 41 had B2 glenoids while 9 had B3 glenoids.




One patient had center-peg osteolysis; 1 patient had glenoid component loosening. Postoperative glenoid component retroversion and residual posterior subluxation relative to the scapular body or glenoid face did not correlate with range of motion or shoulder function. However, humeral head decentering on the glenoid face was moderately associated with lower SANE scores.

2023 Clinical outcome of wedged glenoid reconstruction in anatomic total shoulder arthroplasty for osteoarthritic retroverted glenoid: a minimum 2-year follow-up reviewed 17 patients with a mean preoperative neoglenoid retroversion of 16.7°. The mean improvement was compared to a matched control group demonstrating a comparable magnitude of improvement.







Comment: Glenoid retroversion is common among patients having anatomic total shoulder arthroplasty, yet its importance in determining the outcome of joint replacement is not clear (see Prognostic Value of the Walch Classification for Patients Before and After Shoulder Arthroplasty Performed for Osteoarthritis with An Intact Rotator Cuff). Preoperative CT scans are now commonly used to measure retroversion and to plan its correction, yet the impact of 3D planning on clinical outcomes has not been rigorously determined (see Use of Preoperative CT Scans and Patient-Specific Instrumentation May Not Improve Short-Term Adverse Events After Shoulder Arthroplasty). The articles in the post demonstrate widely varying thresholds for the use of augmented components and little data on the clinical importance of version correction.

As shoulder surgeons we need to keep a keen eye on the strength of clinical evidence supporting the concept that correcting glenoid version and the frequent use of augmented glenoid components is of benefit to our patients. Consider for example the articles below.

2023 Does Glenoid Version and its Correction Impact Outcomes in Anatomic Shoulder Arthroplasty - a Systematic Review recognizes that while there are theoretical advantages to correction of glenoid retroversion in atomic total shoulder arthroplasty, limited information exists on the clinical benefit of correcting glenoid retroversion. The authors reviewed 16 studies evaluating the impact of glenoid retroversion on clinical and radiological outcomes of TSA; nine studies utilized corrective reaming techniques, four studies utilized posteriorly augmented glenoids, and two studies utilized non-corrective reaming techniques. Mean preoperative retroversion ranged from 12.7° to 24°. Eleven studies analyzed the effect of glenoid retroversion on clinical outcomes. The majority of the studies (8/11) did not report any significant association of pre- or postoperative glenoid retroversion on any clinical outcome. Of the three studies that reported significant effects, one study reported a negative association between preoperative glenoid retroversion and PROs, one study reported inferior postoperative abduction in patients with postoperative glenoid retroversion greater than 15 degrees, and one study found an increased clinical failure rate in patients with higher postoperative retroversion. Ten studies reported radiographic results (medial calcar resorption, central peg lucency (CPL) grade, Lazarus lucency grade) at follow-up. Only one study reported a significant effect of pre- and postoperative retroversion greater than 15 degrees on CPL grade. The authors concluded that there is currently insufficient evidence that pre- or postoperative glenoid version influences postoperative outcomes independent of other morphologic factors such as joint line medialization. Given that non-corrective reaming demonstrated favorable postoperative outcomes, and postoperative glenoid version was not significantly and consistently found to impact outcomes, there is inconclusive evidence that correcting glenoid retroversion is routinely required.

Furthermore, Early Radiographic and Clinical Outcomes of Primary Short Stem Anatomic Total Shoulder Arthroplasty with a Peripherally Enhanced Fixation Glenoid: A Multicenter Study "observed glenoid osteolysis in only 5.7% of cases with radiographic follow-up at median 28 months despite wide variation in preoperative glenoid morphology (52% B2 and B3 and only 25% A1)" without using any augmented glenoid components.

All of the above should prompt the search for better clinical evidence to support the currently common use of augmented glenoid components to correct glenoid version in anatomic total shoulder arthroplasty.

You can support cutting edge shoulder research and education that are 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).

Sunday, February 18, 2024

Does the innovation of trabecular metal backed glenoid component improve 5 year total shoulder outcomes?

A Multi-Centre, Randomized Controlled Trial Comparing a Second-Generation Uncemented Trabecular Metal-backed versus Cemented Polyethylene Glenoid Component in Total Shoulder Arthroplasty: Five-year Results reports quality of life, clinical, patient-reported, and radiographic outcomes at five years from a randomized controlled trial comparing a second-generation uncemented trabecular metal-backed glenoid (TM, 46 patients, below right) versus a cemented non-ingrowth polyethylene glenoid (POLY, 47 patients, below left) in patients undergoing a total shoulder arthroplasty (TSA).


There were no preoperative differences between groups with respect to age, sex, or WOOS scores.
At followup, there were no statistical or clinically relevant differences in WOOS or patient-reported outcomes between the two groups.

Metal debris was observed in 11 (23.9%) of the TM shoulders without apparent impact on clinical outcomes.



One TM patient experienced glenoid loosening in the setting of an infection. 

One POLY patient had a minor intraoperative periprosthetic fracture of the glenoid which resolved non-operatively. 

Otherwise there was no radiographic evidence of glenoid loosening in either group.

Comment: This randomized clinical trial showed a minimal rate of glenoid component failure at five years after anatomic total shoulder arthroplasty for both the uncemented trabecular metal-backed glenoid and the cemented non-ingrowth polyethylene glenoid in patients undergoing a total shoulder arthroplasty. They noted no differences in outcome between the two glenoid components.

The authors point out that the osseous integration seen with the TM glenoid has the negative consequence that occurs in the revision setting where prosthesis removal can be extremely challenging and lead to extensive bone loss.

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

Follow on twitter: https://twitter.com/RickMatsen or 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).





Saturday, February 17, 2024

Risk factors for glenoid loosening and cuff tears after anatomic shoulder arthroplasty.

The authors of Risk Factors for Rotator Cuff Tears and Aseptic Glenoid Loosening After Anatomic Total Shoulder Arthroplasty reviewed the factors associated with increased risk of cuff tears and glenoid loosening at two years after anatomic total shoulder arthroplasty in 2,699 patients from an international multicenter study who received the Equinoxe platform implants. 

Postoperative cuff tears were reported in 2.5%; 1.3% had revision surgery because of a cuff tear. Patients were more likely to experience postoperative cuff tears if they had prior surgery on the affected side or were treated with a small glenoid component.

Aseptic glenoid loosening was reported in 4.0%; 3.4% had revision surgery because of glenoid loosening. Patients were more likely to experience glenoid loosening if they were ≤62 years of age at the time of surgery, treated with a small glenoid component, or treated with smooth pegged or keeled glenoid components (as opposed to hybrid glenoid components) 




Comment: a few thoughts about these risk factors

Patient factors:

(1) Patient age ≤62 years - this once more brings up the issue of "how do we choose the treatment of osteoarthritis in younger patients?".

(2) Prior surgery - the nature of the prior surgery is not reported. It seems likely that some of these prior surgeries may have been rotator cuff related, which could account for the observed increase in post-arthroplasty cuff tears.

Surgeon controlled factors:

(1) Small glenoid component - it is not clear whether the increased risk associated with the use of a small glenoid component is related to the size of the native glenoid, to less bony support of the component,  to lesser experience of the surgeon or to other factors.

(2) Non-ingrowth pegged or keeled glenoid components - many surgeons currently prefer glenoid components that provide the opportunity for bony ingrowth instead of smooth pegs or keels.

We've still got a lot to learn.

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

Follow on twitter: https://twitter.com/RickMatsen or https://twitter.com/shoulderarth
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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).

Acromial stress fracture after reverse total shoulder - does component geometry matter?

A 75 year old woman had a reverse total shoulder after two failed rotator cuff repair attempts. As we recognize this indicates three risk factors for acromial stress fracture: female sex, advanced age, and rotator cuff disease.





Preoperative 3D CT planning led to the use of an augmented glenoid component.


Three months after surgery, she developed pain in her posterior acromion. An acromial stress fracture was diagnosed on subsequent CT scan.


It has been suggested that component selection and position may increase the risk of acromial stress fractures (see for example Lateralized reverse total shoulder: abduction damage to the acromion). 

In this case the augmented baseplate lateralized the glenosphere while the varus position of the humeral component lateralized the greater tuberosity.

As a result the tuberosity was at risk for collision with the acromion on abduction.


This collision may be less likely if the glenosphere is not lateralized and if the humeral component is in neutral or slight valgus. 




Comment: Our understanding of risk fractures and prevention of acromial stress fractures is evolving. This case is instructive with respect to the possible role of component position in a patient demographically at risk for this complication.

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

Follow on twitter: https://twitter.com/RickMatsen or 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).





Friday, February 9, 2024

Stemless humeral components for anatomic arthroplasty?



Short stemmed humeral components (above left) allow for loading of the humeral medullary canal. They can be used with eccentric humeral heads. Short stems are more difficult to position centrally in the canal than impaction grafted standard length stems.

Stemless humeral components (above right) allow the positioning of the humeral joint surface independent of an intramedullary stem. They load the humeral epiphysis. They do not allow for the use of eccentric (offset) humeral heads.

Let's review some articles that have tried to compare the results of stemless and short stemmed humeral components in anatomic total shoulder arthroplasty. 

2013 Stemless shoulder prosthesis versus conventional anatomic shoulder prosthesis in patients with osteoarthritis found no difference in outcome or complication rate. Blood loss and operative time were less with the stemless implant.

2014 Radiographic assessment of prosthetic humeral head size after anatomic shoulder arthroplasty found more frequent deviation from the anatomic center of rotation for stemless implants than for stemmed implants.

2019 Radiographic restoration of native anatomy: a comparison between stemmed and stemless shoulder arthroplasty found that radiographic restoration of anatomy was similar for stemmed and stemless shoulder arthroplasty implants.

2020 Prospective, Blinded, Randomized Controlled Trial of Stemless Versus Stemmed Humeral Components in Anatomic Total Shoulder Arthroplasty: Results at Short-Term Follow-up reported identical two-year outcomes scores, complication rates, and loosening rates for stemmed and stemless anatomic total shoulders

2021 Radiographic evaluation of humeral head reconstruction with stemmed and stemless spherical implants compared with stemless elliptical head implants found that spherical stemless humeral heads were superior to spherical stemmed components in recreating anatomic head height and minimizing overhang, but less effective in recreating anatomic center of rotation.

2022 A Comparison of Operative Time and Intraoperative Blood Volume Loss Between Stemless and Short-stem Anatomic Total Shoulder Arthroplasty: A Single Institution's Experience reported that stemless aTSA was associated with a decreased surgical time and less intraoperative blood loss when compared with short stemmed aTSA.  Patients receiving stemless implants had a shorter hospital lengths of stay and lower discharge pain scores.

2022 Surgical time and outcomes of stemmed versus stemless total shoulder arthroplasty The average operative time was 24 minutes less in the stemless cohort compared with the stemmed cohort. There was no difference found in visual analog scale, American Shoulder and Elbow Surgeons, and Single Assessment Numerical Evaluation scores between the cohorts at the 2-year follow-up.

2022 Short-term survival and patient-reported outcome of total stemless shoulder arthroplasty for osteoarthritis are similar to that of stemmed total shoulder arthroplasty: a study from the Danish Shoulder Arthroplasty Registry reported that the 5-year cumulative implant survival rates were 0.96 for stemless TSA and 0.97 for stemmed TSA. While the stemless TSA had a statistically significantly better patient-reported outcomes compared with stemmed TSA, the difference was not deemed to be clinically relevant. 

2022 Outcomes Between Stemmed and Stemless Total Shoulder Arthroplasty: A Systematic Review and Meta-analysis of Randomized Controlled Trials found no differences in  functional or clinical outcomes between stemmed and stemless TSAs. No differences were observed between stemmed and stemless designs in the rate of humeral fracture or risk of revision.

2023 Stemless components lead to improved radiographic restoration of humeral head anatomy compared with short-stemmed components in total shoulder arthroplasty found that mean center of rotation (COR) shift for short stems was 2.7 mm (±1.4 mm) compared with 2.1 mm (±0.9 mm) for stemless implants. The clinical significance of this 0.6 mm difference is unclear. Stemless prostheses were less likely to have significant COR outliers compared with short-stem implants.

2023 Medium-term results of stemless, short, and conventional stem humeral components in anatomic total shoulder arthroplasty: a New Zealand Joint Registry study found no significant difference in revision rate per 100 component-years between stemless (.99) and short-stemmed implants (.54). 

2023 A comparison of revision rates for stemmed and stemless primary anatomic shoulder arthroplasty with all-polyethylene glenoid components: analysis from the Australian Orthopaedic Association National Joint Replacement Registry reported that revision rates for stemmed TSA and stemless TSA did not differ significantly. There was an increased rate of revision for humeral head sizes <44 mm. Surgeon inexperience with anatomic shoulder arthroplasty and non-cross linked polyethylene glenoids were risk factors for stemmed TSA revision. Revision for instability/dislocation was more common for stemless TSA (below right) while loosening was more common for stemmed components (below left).















2024 Radiographic comparison of eccentric stemmed vs. concentric stemless prosthetic humeral head positioning after anatomic total shoulder arthroplasty found that stemless and stemmed aTSA implants have similar rates of satisfactory postoperative humeral head center of rotation.  COR deviation was most commonly in the superomedial direction for both humeral component designs. 

2024 Stemless anatomic total shoulder arthroplasty is associated with less early postoperative pain found that stemless aTSA provided earlier improvement in postoperative shoulder pain compared to matched patients undergoing short-stemmed aTSA. The majority of these differences were no longer evident at 26 weeks postoperatively. There were no differences in pain, patient-reported outcomes, range of motion or strength measures between stemless and short-stem aTSA at 2 years postoperatively.

Comment:
These studies do not show a difference in patient outcomes between anatomic total shoulders performed with stemless or short stemmed humeral components. They do indicate that - with either system - accurate positioning of the prosthetic humeral head is important. Finally, they do suggest that total shoulders performed with a stemless component take less time and incur less blood loss.

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

Follow on twitter: https://twitter.com/RickMatsen or 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).