Why are surgeons performing reverse total shoulders rather than anatomic arthroplasties for cuff intact arthritis?

 In the prior post we reviewed the evidence that - in contrast to reverse arthroplasty (RSA) - anatomic total shoulder arthroplasty (aTSA) is less expensive and provides patients with better comfort and function, fewer serious complications, and safer revision options for complications should they occur.

Paradoxically, however, the proportion of aTSAs being performed for cuff-intact arthritis is dropping precipitously.  

We can speculate on possible reasons for this paradox.

(1) Surgeons may perceive that a lower revision rate for RSA is a positive factor for the patient, when in fact the lower RSA revision rate is due in large part to the fact that some of the most common and serious RSA complications are often not revisable (e.g. pain and poor function, displaced acromial/spine fractures). 

(2) Surgeons may perceive that the RSA is easier to perform. This is, of course, due to the fact that few surgeons have training/experience in performing a basic aTSA, not that the operation is of itself more challenging.

(3) Industry influence and conflicts of interest preferentially motivate the more expensive/profitable RSA option.

(4) Recent "innovations" targeting the use of preoperative planning to achieve high levels of "accuracy and precision" - that may be clinically irrelevant - can make the aTSA unnecessarily complex, expensive and daunting. 

The solution may lie in assuring that shoulder surgeons are well trained in both aTSA and RSA.  This requires that organizations such as AAOS and ASES provide hands-on educational opportunities and that training programs assure that their fellows and residents have a meaningful experience in both.  Interestingly in our most recent round of interviews for our fellowship, a number of applicants reported they had never seen, much less performed, an aTSA.

Below is the basic approach I use for anatomic arthroplasty presented at the amazing Nice Shoulder Course of Pascal Boileau.  These steps may be helpful for surgeons wishing to build their aTSA skills.

Keeping it simple

House Finch

Matsen yard

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aTSA vs RSA for cuff intact arthritis: what is the evidence that informs the choice for each patient?

Both anatomic total shoulder arthroplasty (aTSA) and reverse shoulder arthroplasty (RSA) are considerations for patients with cuff-intact glenohumeral osteoarthritis. Currently many, if not most shoulder surgeons are trending toward RSA. In fact many surgeons have little working experience in performing aTSA. For example, per the Australian registry, the share of primary total shoulder replacements that is anatomic has collapsed from roughly 57% in 2008 to about 4% by 2024, while stemmed reverse has risen to nearly 90% (see figure below) [1]. In some circles the pro RSA argument is based on the contentions that (1) the RSA is easier to perform by less experienced-as well as experienced-surgeons and (2) the RSA as a lower rate of revision.

A look at the published evidence may inform the choice for patients and surgeons:

1. Patient-reported outcomes

With commonly used scores, the two types of arthroplasty seem similar for cuff-intact arthritis. A 2026 meta-analysis of 1,716 patients aged ≥70 with a competent cuff found no significant differences in ASES, Constant, or SST scores [2]. A meta-analysis of 14 studies (4,819 cases) found similar ASES, Constant, SST, SSV, and VAS pain scores [3], as did an earlier systematic review [4] and a propensity score–matched JBJS analysis [5]. 

However, in the UK National Joint Registry, roughly a quarter of 21,918 RSA patients had an “unsatisfactory” Oxford Shoulder Score (<29) [6]. Single-center series using patient-acceptable-symptom-state (PASS) thresholds put the figure higher — 25–40% of RSA patients failed to reach PASS for ASES or SANE at two years [7], and 34–35% still failed at minimum five years [8], with pain the primary factor in these adverse outcomes. 

With the Shoulder Arthroplasty Smart score, aTSA achieved higher absolute postoperative scores even though the improvement from baseline was similar [9]. Among patients who reached a “new normal” (defined as a SANE score  ≥95), aTSA significantly outperformed RSA on higher-demand tasks, motion, and return to sport and work [10]. 

2. Motion 

Across the comparative meta-analyses, aTSA delivered better external and internal rotation, with differences that exceed the MCID and reached 10–11° of external rotation in pooled estimates [2,3,4] as well as  better overall motion in matched cohorts [5]. Rotation enables the patient to perform basic activities of daily living: dressing, toileting, perineal care, and reaching behind the back.

3. Complications

In pooled comparative data, RSA carried a lower overall complication rate than aTSA in the cuff-intact population [2,3]. But the complications the two implants produced differed in kind. Historically, primary stemmed anatomic shoulders done for osteoarthritis using legacy techniques and implants have been revised chiefly for glenoid component loosening (29.1%), rotator cuff insufficiency (27.6%), and instability/dislocation (23.1%), with loosening being predominant [1]. Stemmed reverse shoulders have been revised chiefly for instability/dislocation, infection, loosening, and fracture [1]. 

4. Revision 

At ten years, cumulative percent revision (all diagnoses, modern prostheses) was 5.5% for stemmed reverse, 5.2% for stemless aTSA, and 7.9% for stemmed aTSA (Figure 2 below) [1]. 

It is worthwhile noting that the 7.9% ten-year revision rate for stemmed aTSA includes decades of older, non-crosslinked polyethylene. When the glenoid is crosslinked, aTSA durability improves markedly: in a dedicated AOANJRR study of 10,102 stemmed aTSAs done for osteoarthritis, non-crosslinked polyethylene had more than double the revision risk of crosslinked polyethylene after 18 months (HR 2.3; 95% CI 1.6–3.1), with 12-year cumulative revision of 9% versus 5% [22]. Considering only crosslinked anatomic glenoids, the revision rate for stemmed aTSAs (5%) was comparable to stemmed RSA (5.5%) and stemless aTSA (5.2%). 

Vitamin E–stabilized polyethylene is a type of crosslinked polyethylene, and registries tend to pool the two.  Vitamin E reduces wear and osteolytic particle debris on the bench [23], but no study has yet demonstrated a vitamin-E–versus–plain-crosslinked revision difference in shoulder arthroplasty.

The revision rates for stemless aTSA match those for the RSA; the reasons for this are not clear - perhaps more experienced surgeons, greater ability to achieve the desired humeral component position,  a higher rate of use of modern glenoid components, and/or preferential selection of healthier shoulders with better quality bone. 

Comparative meta-analyses report RSA revision rates about four-fold lower than aTSA in the cuff-intact analysis, OR 0.43; 95% CI 0.29–0.65; p<0.001) [3], although an earlier meta-analysis found no mid-term difference (OR 0.33; p=0.16) [4]. A 2026 propensity-matched study showed a lower early revision rate for aTSAs, but at midterm followup the revision rate increased [12].

However, it is critical to recognize that revision is a poor proxy for clinical failure in RSA. A National Joint Registry analysis concluded that low RSA revision rates may not signify implant success. Instead, patients with poor outcomes and their surgeons may be reluctant to undertake complex RSA revisions which have unpredictable results.[6]. The point is apparent for the most common mode of RSA failure — a painful, poorly functioning but radiographically satisfactory RSA. Such an outcome is experienced by about a quarter of RSA patients [6,7,8], yet RSAs are rarely revised for this indication. A failure that is not revised never appears in the revision rate.

[Complication frequencies were drawn from indexed systematic reviews [26–29] (e.g., PJI 2.4%, acromial/scapular fracture 2.5%, primary-RSA instability 2.5%); the revisability column reflects their reported management — acromial fractures are predominantly treated non-operatively, instability usually presents within 90 days and is treated by component revision, and infection is nearly always surgical. The registry anchor for pain/PROM failure is O’Malley [6].]

The different failure types are not equally salvageable. If an anatomic shoulder fails, it can usually be converted to a RSA with outcomes that approach those of primary RSA.  Primary stemmed anatomic shoulders done for osteoarthritis are revised to a reverse in 89% of cases, keeping the original humeral stem 58% of the time [1]; 93.8% of failed stemless aTSAs are converted to RSAs. On the other hand, revision of a failed reverse to another reverse often fails to yield the desired improvement in comfort and function.

5. Durability

Durability matters most for the patient with decades of active use ahead. At minimum ten-year follow-up, aTSAs sustain their functional gains for primary osteoarthritis [13], the large concurrent aTSA experience supports this option in the high-demand patient who wishes to avoid a RSA [14]. The Australian registry shows modern stemless anatomic matching reverse on revision out to ten years, and crosslinked stemmed-anatomic glenoids more than halve the revision risk of older non-crosslinked ones [1,22].

6. Return to sport 

Return-to-sport rates are high after both implants and highest after aTSA in pooled data [15]. A recent large weightlifting series reported high self-rated comfort, yet its endpoint is a single ordinal “difficulty” item — capturing neither the amount of load nor performance. [16]. When actual one-repetition-max recovery is measured, returners perform below their presymptomatic level, with the largest decrement in bench press [17]. 

7. Surgeon capability. It is often said that a good aTSA outperforms a good RSA, which outperforms a bad aTSA, which outperforms a bad RSA [18].  Some say it is technically easier to do a good RSA than an aTSA (not my view). However it is for sure that as aTSA volume falls, fewer surgeons will be able to reliably provide a good anatomic to their patients with cuff intact arthritis. While some hold that navigation, patient-specific instrumentation, and robotics may improve component positioning; none has been shown to improve patient-reported outcomes or reduce complications for any type of arthroplasty [19,20,21]. It appears that the surgeon is sill the method.

So, in rough summary

Bottom line: 

The patient and the surgeon considering arthroplasty for cuff intact shoulder arthritis should discuss the available evidence on aTSA and RSA.

An aTSA - when performed by a surgeon who can deliver a reliable aTSA -  may be attractive when function and salvageability matter most —  particularly in the more active patient with a reconstructable glenoid.

A RSA may be more attractive in the less active patient, or one whose glenoid morphology or bone quality makes a durable aTSA less certain or when the shoulder surgeon is not comfortable performing an anatomic shoulder arthroplasty.

Two cautions bear on the consideration: the revision rate understates RSA failure, because its most common failure — a painful but intact shoulder — is rarely revised [6]; and roughly a quarter of RSA patients do not reach a satisfactory outcome at all [6,7,8]. 

A choice

Pileated Woodpeckers

Seattle

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References

[1]Lewis PL, Gill DR, McAuliffe MJ, et al. Hip, Knee and Shoulder Arthroplasty: 2025 Annual Report. Australian Orthopaedic Association National Joint Replacement Registry. AOA: Adelaide; 2025. doi:10.25310/MXFR3061. (Figures ST1, ST2; Tables ST6, ST39, ST46–47, ST76.)

[2]Gupta MS, Krishan A, Rashid A, et al. Reverse versus anatomic total shoulder arthroplasty in patients over 70 with a competent rotator cuff and glenohumeral osteoarthritis: a meta-analysis. J Shoulder Elbow Surg. 2026 (online 2025). PMID: 41276069.

[3]Thamrongskulsiri N, Limskul D, Tanpowpong T, et al. Comparison of revision rates and clinical outcomes between anatomic and reverse total shoulder arthroplasty for rotator cuff-intact osteoarthritis: a systematic review and meta-analysis. Clin Orthop Surg. 2025;17(6):907–921. doi:10.4055/cios25012.

[4]Kim H, Kim CH, Kim M, et al. Is reverse total shoulder arthroplasty more advantageous than anatomic TSA for osteoarthritis with intact cuff tendon? A systematic review and meta-analysis. J Orthop Traumatol. 2022;23(1):3. PMID: 34993646.

[5]Kirsch JM, Puzzitiello RN, Swanson D, et al. Outcomes after anatomic and reverse shoulder arthroplasty for glenohumeral osteoarthritis: a propensity score-matched analysis. J Bone Joint Surg Am. 2022. PMID: 35867705.

[6]O’Malley O, Davies A, Sabharwal S, et al. Is there a difference in thresholds for revision between shoulder arthroplasty types? A National Joint Registry study. PLoS One. 2025. doi:10.1371/journal.pone.0330975.

[7]Werner BC, Lederman E, Gobezie R, et al. Understanding the variables associated with failure to achieve an acceptable symptom state after reverse shoulder arthroplasty. Semin Arthroplasty JSES. 2021.

[8]Ardebol J, et al. Defining the MCID and PASS following reverse shoulder arthroplasty for glenohumeral arthritis or cuff tear arthropathy at minimum 5-year follow-up. JSES Int. 2025.

[9]Marigi EM, Hao KA, Friedman RJ, et al. Exactech Equinoxe anatomic versus reverse total shoulder arthroplasty for primary osteoarthritis: case-controlled comparisons using the machine learning-derived Shoulder Arthroplasty Smart score. J Shoulder Elbow Surg. 2023. PMID: 39292145.

[10]Beleckas CM, Schodlbauer DF, Mousad AD, et al. Evaluation of new normal after shoulder arthroplasty: comparison of anatomic vs. reverse total shoulder arthroplasty. J Shoulder Elbow Surg. 2025;34:S43–S49. doi:10.1016/j.jse.2025.02.010. PMID: 40074195.

[11]Barco R, Savvidou OD, Sperling JW, et al. Complications in reverse shoulder arthroplasty. EFORT Open Rev. 2016;1:72–80. doi:10.1302/2058-5241.1.160003.

[12]Leinweber KA, Bowler AR, Diestel DR, et al. Reverse and anatomic total shoulder arthroplasty for glenohumeral osteoarthritis: a propensity-matched comparison at early and midterm follow-up. J Shoulder Elbow Surg. 2026. PMID: 41564999.

[13]Sharareh B, Whitson AJ, Matsen FA III, et al. Minimum 10-year follow-up of anatomic total shoulder arthroplasty and ream-and-run arthroplasty for primary glenohumeral osteoarthritis. J Shoulder Elbow Surg. 2024;33(6):1276–1284. PMID: 37777045.

[14]Matsen FA III, Whitson A, Jackins SE, et al. Ream and run and total shoulder: patient and shoulder characteristics in five hundred forty-four concurrent cases. Int Orthop. 2019;43(9):2105–2115. PMID: 31240359.

[15]Liu JN, Steinhaus ME, Garcia GH, et al. Return to sport after shoulder arthroplasty: a systematic review and meta-analysis. Knee Surg Sports Traumatol Arthrosc. 2018;26(1):100–112. PMID: 28409200.

[16]Abdelshaheed J, Chatterji R, Levy J, et al. Return to weightlifting following anatomic and reverse shoulder arthroplasty. J Shoulder Elbow Surg. 2026;35:1660–1666. doi:10.1016/j.jse.2026.02.002.

[17]Ames A, Shah SS, Pettit R, et al. Against surgeons’ advice: the return to sport in high-demand weightlifters following anatomic total shoulder arthroplasty at average 3.6 years’ follow-up. J Shoulder Elbow Surg. 2023;32(4):e153–e159. doi:10.1016/j.jse.2022.09.027.

[18]Menendez ME, Garrigues GE, Jawa A. Clinical Faceoff: anatomic versus reverse total shoulder arthroplasty for primary glenohumeral osteoarthritis. Clin Orthop Relat Res. 2022;480(11):2095–2100.

[19]Daher M, Fares MY, Boufadel P, et al. Patient-specific instrumentation in primary total shoulder arthroplasty: a meta-analysis of clinical outcomes. Clin Shoulder Elb. 2025;28(2):129–136. doi:10.5397/cise.2024.01095.

[20]Patient-specific instrumentation in shoulder arthroplasty: high tech, low yield? [editorial]. Clin Shoulder Elb. 2025;28(2). doi:10.5397/cise.2025.00423.

[21]Gaj E, Pagnotta SM, Berlinberg EJ, et al. Intraoperative navigation system use increases accuracy of glenoid component inclination but not functional outcomes in reverse total shoulder arthroplasty. Arch Orthop Trauma Surg. 2024;144(1):91–102. doi:10.1007/s00402-023-05038-y.

[22]Page RS, Alder-Price AC, Rainbird S, et al. Reduced revision rates in total shoulder arthroplasty with crosslinked polyethylene: results from the Australian Orthopaedic Association National Joint Replacement Registry. Clin Orthop Relat Res. 2022;480(10):1940–1949. doi:10.1097/CORR.0000000000002293. PMID: 35901440.

[23]Khan AZ, Maxwell MJ, Parrott RM, et al. Effect of vitamin E–enhanced highly cross-linked polyethylene on wear rate and particle debris in anatomic total shoulder arthroplasty: a biomechanical comparison to ultrahigh-molecular-weight polyethylene. J Shoulder Elbow Surg. 2024. PMID: 38182025.

[24]Gowd AK, Liu JN, Cabarcas BC, et al. Single Assessment Numeric Evaluation and patient acceptable symptom state thresholds following shoulder arthroplasty. J Shoulder Elbow Surg. 2021. (PASS: ASES 81.9, SANE 75.5; n=207, mixed TSA/RSA.)

[25]DeVito P, Damodar D, Berglund DD, et al. Predicting outstanding results after reverse shoulder arthroplasty using percentage of maximal outcome improvement. J Shoulder Elbow Surg. 2019;28(6):1223–1231. PMID: 30910258. (SST threshold 61.3% MPI; n=198.)

[26]Shah SS, Gaal BT, Roche AM, et al. The modern reverse shoulder arthroplasty and an updated systematic review for each complication: part I. JSES Int. 2020;4(4):929–943. (Periprosthetic joint infection 2.4% for primary RSA.)

[27]Shah SS, Roche AM, Sullivan SW, et al. The modern reverse shoulder arthroplasty and an updated systematic review for each complication: part II. JSES Int. 2020;5(1):121–137. doi:10.1016/j.jseint.2020.07.018. PMID: 33554177. (Instability, humerus/glenoid fracture, acromial/scapular-spine fracture.)

[28]Zumstein MA, Pinedo M, Old J, et al. Problems, complications, reoperations, and revisions in reverse total shoulder arthroplasty: a systematic review. J Shoulder Elbow Surg. 2011;20(1):146–157.

[29]Lau SC, Large R. Acromial fracture after reverse total shoulder arthroplasty: a systematic review. Shoulder Elbow. 2020;12(6):375–389. doi:10.1177/1758573219876486. PMID: 33281942.

"RSA has a lower revision rate than aTSA". Why that may not mean what you think it does.

.

Disclaimers: I have no relationships with any implant company. I do love anatomic total shoulder arthroplasty. The below is my attempt to analyze the available data, but there is a dearth of high-level evidence. I am not a statistician, but here I share my attempt at a deep dive into an important and hotly discussed issue. It is not a quick read, but the topic deserves the depth.

The relative merits of anatomic and reverse total shoulder arthroplasty for osteoarthritis are—and probably will forever be—hotly debated. Many factors contribute to surgeons' views on this topic, including indications, relative difficulty of the procedure, cost, need for preoperative 3D/CT-based planning, need for transfer technologies (robotics, patient-specific instruments, virtual/augmented reality), and the patient's anticipated postoperative comfort, range of motion, and function. In this post, we take a look at the contention that patients whose osteoarthritis is treated with reverse total shoulder arthroplasty have lower rates of revision than those treated with anatomic total shoulder arthroplasty.

The word on the street is that patients having reverse total shoulder arthroplasty (RSA) are less likely to undergo revision than patients having anatomic total shoulder arthroplasty (aTSA). For example, the Australian Orthopaedic Association National Joint Replacement Registry's 2025 Annual Report puts the 10-year cumulative revision rate at 7.4% for aTSA and 5.4% for RSA [1]. The 14-year figures are 9.5% and 6.4%. These numbers are often cited in support of expanding RSA into indications it was not originally designed for—including osteoarthritis with an intact rotator cuff.

Set against those numbers, a finding from O’Malley and colleagues' 2025 National Joint Registry analysis of 21,918 patients should give us pause. RSA had nearly twice the prevalence of unsatisfactory function—Oxford Shoulder Score below 29—as aTSA: 27.0% versus 15.4%. Yet RSA patients with unsatisfactory function were less than half as likely to undergo revision (4.9% vs. 10.6%, p < 0.001) [6]. The implant with the lower revision rate (RSA) is the implant under which a larger proportion of patients are living with poor function.

That paradox is the subject of this post. Two sampling biases and one structural property of the metric itself combine to make revision rate a misleading proxy for clinical success when comparing aTSA to RSA. The first is a confounding mismatch between the patient populations the two operations are performed on. The second is an attrition mechanism that systematically removes the worst outcomes from any cohort with a minimum time to follow-up. The third—and the most important one is that revision rate measures what the surgeon decides to operate on again, not what the patient is living with. Strip these out and the registry-based case for RSA in osteoarthritis with intact cuff is weak.

Two biases and a metric problem

Bias 1: The patient populations are not the same

Restricting to osteoarthritis controls for the obvious confounders of other indications such as cuff tear arthropathy and fracture; even within that restriction, the AOANJRR shows aTSA at 7.7% revision at 10 years and RSA at 5.0% [1]. But the RSA-for-OA cohort is overwhelmingly older: 87.7% of cases are in patients aged 65 or older [1]. When attention is restricted to the demographic where the operations actually compete—younger patients with osteoarthritis—the favorable RSA signal disappears. Figure 1 shows the actual curves from the registry.

Figure 1.  Cumulative percent revision from the AOANJRR 2025 Annual Report. RSA for OA in patients aged <65 (n=3,439, Table ST85) versus aTSA with a polyethylene glenoid for OA, all ages (n=5,120, Table ST44). Markers at the registry's reported time points (1, 3, 5, 7, 10, 14 years); shaded bands show 95% confidence intervals. The RSA <65 curve runs above the aTSA curve at every reported time point. At 14 years RSA <65 reaches 13.2% (95% CI 9.6–17.9) versus 9.4% (95% CI 7.8–11.1) for aTSA—the ratio of point estimates is 1.40. The wide 14-year RSA confidence interval reflects the small number of patients still under follow-up at that time point (n=53), an example of the cohort attrition discussed under Bias 2.  aTSA n-at-risk approximated from Figure ST2 of the AOANJRR 2025 report (all-diagnosis polyethylene glenoid, n=5,413) scaled to the OA-only cohort. RSA n-at-risk taken directly from Table ST85.

Cautions about this comparison are in order. The under-65 RSA-OA cohort is itself selected: these patients typically have severe pathology not amenable to aTSA, so part of their failure rate may reflect disease severity rather than implant inferiority. And the aTSA comparison group is not age-matched. Thus the registry cannot fully answer the like-for-like question—younger patient with intact cuff, RSA versus aTSA—because surgeons mostly do not choose RSA for that patient, and so the comparison cases barely exist. What the registry can show is that the apparent RSA-OA advantage in the registry headline is overwhelmingly driven by older patients for whom aTSA was never going to be offered.

Bias 2: The cohorts are themselves selectively curated

Every minimum-follow-up cohort is, by construction, a survivor cohort. To be analyzed at minimum 2, minimum 5, or minimum 10 years, a patient must have remained alive, in clinic, and with the original implants in place. Patients are excluded if their shoulder was revised before the minimum follow-up, if they died, if they were lost to follow-up, or if they left the surgeon's practice. This is not random. The mechanism is the immortal time bias formalized by Suissa: when cohort entry depends on a span of time during which the outcome of interest (e.g., survivorship to the minimum follow-up time) could not occur, the estimated event rate is systematically biased toward the experience of survivors [2]. Including only patients with minimum two-year follow-up systematically excludes those revised or deceased before two years; the percentage excluded by this immortal time effect grows for minimum five-year follow-up and grows again for minimum ten-year follow-up. This exclusion leaves a “purified” sample of patients more likely to continue life without revision and does not reflect the overall revision risk of the initial cohort.

Three independent processes drive this attrition. Khan and colleagues used Medicare claims on 108,667 elective shoulder arthroplasty patients aged 65 or older and reported 5-year mortality of 14.9% in elective non-fracture cases [3]. Torrens and colleagues prospectively tracked 251 shoulder arthroplasty patients and reported cumulative loss to follow-up of 18.3% at 2 years, 31.5% at 5 years, and 34.3% at 7 years, with older, sicker, and more obese patients selectively lost (HR 1.05 per year of age, HR 2.44 for severe obesity, HR 1.93 per ASA point) [4]. After adding exclusion for pre-threshold revision, at minimum 10-year follow-up only a minority of the original cohort—roughly a quarter to a third—remains analyzable. The minimum-10-year revision rate commonly quoted from a published series is therefore drawn from the least at-risk fraction of the original patient population.

Figure 2.  Approximate share of an original elective shoulder arthroplasty cohort still available for analysis at minimum 2-, 5-, and 10-year follow-up. Mortality components anchored to Khan 2024 [3] (14.9% at 5 years extrapolated to ~30% at 10 years); loss-to-follow-up components anchored to Torrens 2022 [4] (18.3% at 2 years, 31.5% at 5 years, extrapolated to ~36% at 10 years); pre-threshold revision approximated from registry data.

This compounds asymmetrically with the demographic confounding above. RSA cohorts are older and have higher all-cause mortality, so these cohorts lose more patients to death between landmark thresholds. RSA's particular failure modes—acromial fracture, dissatisfaction with limited internal rotation, persistent pain—are also more likely to lead to patients quietly dropping out of follow-up because there is often no good surgical option for them to consider. A published “minimum 5-year RSA-OA revision rate” of 3.5% is best read as 3.5% of the best segment of the original cohort, not the entire cohort. The same dynamic appears directly in Figure 1: at the 14-year time point the RSA <65 cohort retains only 53 of the original 3,439 patients (1.5%), producing the wide confidence interval that runs from 9.6% to 17.9%.

The metric problem: failure is not the same as revision

This is the largest of the three issues, and the one with the most specific mechanism. Revision rate is commonly used as a surrogate for clinical failure. It is a particularly poor surrogate for RSA. Parada and colleagues reported a 10.7% complication rate and 5.6% revision rate for aTSA, versus 8.9% and 2.5% for RSA, in 1,128 cases at mean follow-up of 23 months [5]. The gap between complication and revision was 3.6-fold for RSA versus 1.9-fold for aTSA. The most common RSA complication—acromial or scapular fracture (2.5%)—had a 0% revision rate [5].

O’Malley and colleagues' finding closes the loop: twice the prevalence of unsatisfactory function after RSA, and less than half the rate at which that unsatisfactory function leads to revision [6]. The lower RSA revision rate does not reflect superior implant performance. It reflects a higher threshold for revision in an older, frailer cohort, combined with failure modes that are difficult to address surgically and that surgeon and patient usually choose to accept rather than trying to fix surgically.

Figure 3.  Cumulative revision rate (light bars) and cumulative clinical failure rate (dark bars) for aTSA and RSA at minimum 2-, 5-, and 10-year follow-up. Revision rates anchored to AOANJRR registry data [1]; clinical failure rates anchored to Parada complication rates [5] and O’Malley OSS<29 prevalence [6]. The clinical-failure-to-revision ratio is approximately 3-fold for aTSA across all time points and 5- to 6-fold for RSA.

The asymmetry has a specific cause: the failure modes that drive each operation's clinical burden carry very different probabilities of leading to revision. Most of the failure modes unique to RSA produce clinical problems that rarely lead to revision.

A mode-by-mode look

Figure 4.  Estimated cumulative incidence of patients clinically affected by each failure mode (light bars) versus the proportion undergoing revision attributable to that mode (dark bars). Constructed from AOANJRR revision-cause distributions [1], Parada complication rates [5], O’Malley OSS<29 prevalence [6], systematic-review data on acromial fracture [7–9], Young secondary cuff dysfunction rates [14], Papadonikolakis glenoid radiolucency rates [10], Olson RSA instability rates [15], and Rojas baseplate loosening rates [16].

Acromial and scapular fracture. This mode is unique to RSA and represents the largest disconnect in the literature. Three independent systematic reviews place the incidence at 2.8% (Mahendraraj 2019) [8], 4.0% (Kim 2019) [9], and 5.0% (Patterson 2020) [7]. Of 208 fractures in Patterson's review, only 9 (4.3%) underwent revision arthroplasty [7]. Function deteriorates after fracture regardless of treatment. The clinical-failure-to-revision ratio is approximately 25:1.

Persistent pain. Pain is a major driver of unsatisfactory function but rarely the documented reason for revision. The OSS<29 prevalence in O’Malley—15.4% for aTSA and 27.0% for RSA—captures pain alongside stiffness, ADL limitation, and overall functional compromise [6]. The cleanest reading is the one O’Malley reports directly: RSA patients with poor function are less than half as likely as aTSA patients with poor function to be revised. Some unknown proportion of persistent pain after shoulder arthroplasty represents occult Cutibacterium infection that goes undiagnosed; Pottinger and colleagues showed that 22% of revisions performed for stiffness, pain, or loosening had positive cultures for Cutibacterium despite being categorized clinically as aseptic [11]. Patients with low-grade unrecognized infection who do not undergo revision are invisible in registry data altogether.

Cuff and subscapularis failure. This mode is aTSA-specific. Cuff insufficiency accounts for roughly a quarter of aTSA-OA revisions in the AOANJRR data [1]. The actual prevalence of post-aTSA cuff failure is substantially higher. Young and colleagues, in a multicenter European study of 518 aTSAs followed for a mean of 8.6 years, reported a 16.8% rate of secondary rotator cuff dysfunction, with Kaplan–Meier survivorship free of secondary cuff dysfunction of 100% at 5 years, 84% at 10 years, and 45% at 15 years [14]. Most of this dysfunction was managed with rehabilitation or accepted as part of the clinical course; only a fraction underwent revision. RSA bypasses the rotator cuff biomechanically, so this mode does not apply to RSA. Importantly, aTSA failure due to cuff or glenoid component issues can be revised to RSA with patient-reported outcome improvements [12,13]—a salvage option that is less successful for some of the major RSA-specific failure modes.

Asymptomatic glenoid radiolucency and loosening. aTSA-specific. Papadonikolakis, Neradilek, and Matsen's 2013 systematic review of 27 articles representing 3,853 aTSAs reported asymptomatic glenoid radiolucent lines accumulating at 7.3% per year, symptomatic loosening at 1.2% per year, and surgical revision for loosening at 0.8% per year [10]. Radiographically apparent loosening occurs approximately nine times more frequently than revision. Most asymptomatic radiolucent lines do not progress to clinical failure within the patient's lifetime, but those that do represent a substantial population not captured in revision rates.

Dislocation and instability. Both operations can fail by this mode, but RSA more often. Olson and colleagues' systematic review of 17 studies including 7,885 RSAs reported a pooled instability rate of 2.5%, ranging from 1–5% in primary RSA cohorts and 1–49% in revision RSA [15]. Across studies, treatment was successful with closed reduction and casting in 28–100% of cases and with revision RSA in 55–100%; recurrent instability often required hemiarthroplasty or resection. The clinical-failure-to-revision ratio for instability is approximately 1.5:1 to 2:1—smaller than for the modes above, but RSA-specific risk factors (subscapularis insufficiency, proximal humerus fracture, fracture sequelae) load this mode disproportionately onto the older RSA-for-fracture population.

Baseplate failure (RSA) and overt infection (both RSA and aTSA). These are the modes with the smallest disconnect. Aseptic glenoid baseplate loosening is rare: Rojas and colleagues' meta-analysis of 103 studies including 6,583 RSAs reported a pooled prevalence of 1.16% (95% CI 0.80–1.69%), with 0.90% in primary RSA and 1.69% in revision RSA [16]. When symptomatic, baseplate loosening almost always progresses to revision. Overt infection is similarly almost always revised. Both modes have clinical-failure-to-revision ratios close to 1:1—but the Pottinger finding indicates that the population of patients with low-grade unrecognized infection may be substantially larger than overt-infection counts suggest, and many of those patients neither receive a revision nor appear in registry infection data [11].

Bottom line

The AOANJRR shows a population-level revision-rate advantage for RSA over aTSA. It does not show a like-for-like advantage. Two sampling biases compound: an age and indication mismatch that places most RSA-for-OA cases in older patients to whom aTSA was never going to be offered, and an immortal time bias that removes most of an original cohort from the analyzed group at the 10-year mark, with the older RSA population hit hardest. The third issue is structural rather than statistical. Revision rate measures the surgeon's and patient's thresholds for re-operation, and does not reflect the patient's clinical outcome. The clinical-failure-to-revision ratio is two to three times larger for RSA than for aTSA.

This is not an artifact. It has a specific mechanism. RSA's distinctive failure modes—acromial fracture, persistent pain, scapular notching, dissatisfaction with internal rotation—are largely uncountable in revision data because there is often no good surgical option to consider. By contrast, aTSA failures from cuff or subscapularis tear and from glenoid component loosening can be revised to RSA with clinically significant outcome improvements [12,13]. Revision rate as a quality metric privileges the operation (RSA) whose failures are less likely to be surgically correctable.

Evidence for restricting RSA to its established indications—cuff arthropathy, irreparable cuff tear, selected fractures—rather than expanding it into osteoarthritis with intact cuff is present in the AOANJRR's data.

avocet

reverse avocet

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References

1. Australian Orthopaedic Association National Joint Replacement Registry. Hip, Knee and Shoulder Arthroplasty: 2025 Annual Report. Adelaide: AOA; 2025. Available from: https://aoanjrr.sahmri.com/annual-reports-2025. Data period 1 September 1999 – 31 December 2024.

2. Suissa S. Immortal time bias in pharmacoepidemiology. Am J Epidemiol. 2008;167(4):492–499. doi:10.1093/aje/kwm324. PMID: 18056625.

3. Khan AZ, Zhang X, Macarayan E, et al. Five-year mortality rates following elective shoulder arthroplasty and shoulder arthroplasty for fracture in patients over age 65. JBJS Open Access. 2024;9(2):e23.00133. doi:10.2106/JBJS.OA.23.00133. PMID: 38685966.

4. Torrens C, Martínez R, Santana F. Patients lost to follow-up in shoulder arthroplasty: descriptive characteristics and reasons. Clin Orthop Surg. 2022;14(1):112–118. doi:10.4055/cios21034. PMID: 35251548.

5. Parada SA, Flurin PH, Wright TW, Zuckerman JD, Elwell JA, Roche CP, Friedman RJ. Comparison of complication types and rates associated with anatomic and reverse total shoulder arthroplasty. J Shoulder Elbow Surg. 2021;30(4):811–818. doi:10.1016/j.jse.2020.07.028. PMID: 32763380.

6. O’Malley O, Davies A, Rangan A, Sabharwal S, Reilly P. Is there a difference in thresholds for revision between shoulder arthroplasty types? A National Joint Registry study. PLoS One. 2025;20(8):e0330975. doi:10.1371/journal.pone.0330975. PMID: 40857270.

7. Patterson DC, Chi D, Parsons BO, Cagle PJ. Acromial spine fracture after reverse total shoulder arthroplasty: a systematic review. J Shoulder Elbow Surg. 2019;28(4):792–801. doi:10.1016/j.jse.2018.08.033. PMID: 30497925.

8. Mahendraraj KA, Abboud J, Armstrong A, et al. How common are acromial and scapular spine fractures after reverse shoulder arthroplasty? A systematic review. Bone Joint J. 2019;101-B(6):627–634. doi:10.1302/0301-620X.101B6.BJJ-2018-1187.R1. PMID: 31154841.

9. Kim HM, Chung J, Jeong CW, Yoon JR. Is acromial fracture after reverse total shoulder arthroplasty a negligible complication? A systematic review. Clin Orthop Surg. 2019;11(4):427–435. doi:10.4055/cios.2019.11.4.427. PMID: 31788166.

10. Papadonikolakis A, Neradilek MB, Matsen FA 3rd. Failure of the glenoid component in anatomic total shoulder arthroplasty: a systematic review of the English-language literature between 2006 and 2012. J Bone Joint Surg Am. 2013;95(24):2205–2212. doi:10.2106/JBJS.L.00552. PMID: 24352774.

11. Pottinger P, Butler-Wu S, Neradilek MB, Merritt A, Bertelsen A, Jette JL, Warme WJ, Matsen FA 3rd. Prognostic factors for bacterial cultures positive for Propionibacterium acnes and other organisms in a large series of revision shoulder arthroplasties performed for stiffness, pain, or loosening. J Bone Joint Surg Am. 2012;94(22):2075–2083. doi:10.2106/JBJS.K.00861. PMID: 23172325.

12. Al-Asadi M, Rajapaksege N, Abdel Khalik H, Abesteh J, Athwal GS, Khan M. Outcomes and complications of failed anatomic shoulder arthroplasty revised with reverse arthroplasty: a systematic review. J Shoulder Elbow Surg. 2025;34(7):1832–1840.

13. Tobin JG, Thomas SK, Elwell JA, Roche CP, Rogalski BL, Eichinger JF, Friedman RJ. Anatomic total shoulder arthroplasty revised to reverse total shoulder arthroplasty: clinical and radiographic outcomes compared to primary reverse total shoulder arthroplasty. J Shoulder Elbow Surg. 2025;34(6):1525–1531. PMID: 39694226.

14. Young AA, Walch G, Pape G, Gohlke F, Favard L. Secondary rotator cuff dysfunction following total shoulder arthroplasty for primary glenohumeral osteoarthritis: results of a multicenter study with more than five years of follow-up. J Bone Joint Surg Am. 2012;94(8):685–693. doi:10.2106/JBJS.J.00727. PMID: 22419408.

15. Olson JJ, Galetta MD, Keller RE, Oh LS, O’Donnell EA. Systematic review of prevalence, risk factors, and management of instability following reverse shoulder arthroplasty. JSES Rev Rep Tech. 2022;2(3):261–268. doi:10.1016/j.xrrt.2022.02.009. PMID: 37588866.

16. Rojas J, Choi K, Joseph J, Srikumaran U, McFarland EG. Aseptic glenoid baseplate loosening after reverse total shoulder arthroplasty: a systematic review and meta-analysis. JBJS Rev. 2019;7(5):e7. doi:10.2106/JBJS.RVW.18.00132. PMID: 31145263.

Component malposition and clinical outcomes in shoulder arthroplasty - are they related?

It seems intuitive that substantial malposition of shoulder arthroplasty components can lead to poor clinical outcomes.  

The assumption that malposition drives poor outcomes has become the rationale for investment in three-dimensional planning, patient-specific instrumentation, navigation, augmented reality, and robotics. However, examination of published evidence indicates that the relationship between measured component position and patient-reported outcomes is weaker than this narrative implies. For example Negligible Correlation between Radiographic Measurements and Clinical Outcomes in Patients Following Primary Reverse Total Shoulder Arthroplasty concluded that the relationship between measured component position and clinical outcomes is limited. Does postoperative glenoid component retroversion following anatomic total shoulder arthroplasty affect clinical outcomes? A systematic review and meta-analysis found no clinically significant difference in patient-reported outcome scores, range of motion, or complications for anatomic total shoulder arthroplasty glenoid components implanted with <15° versus ≥15° of postoperative retroversion across 15 studies and 1,190 shoulders. 

Humeral and glenoid component malposition in patients requiring revision shoulder arthroplasty: a retrospective, cross-sectional study measured component positions for TSA and RSA on pre-revision radiographs of patients having revision arthroplasty and compared these measures to "ideal" values for glenoid inclination, critical shoulder angle, glenosphere overhang, change in center of rotation, humeral head height, acromio-humeral interval, and humeral stem alignment. These measurements were not made on radiographs obtained immediately after the index arthroplasty, so the extent of postoperative component shift is not known.

The article found that the majority of glenoid components in these revision cases were malpositioned in relation to the "ideal" values for both TSA (51%) and RSA (93%) when all of the measures were considered. Similarly, there was humeral component malposition in 57% of TSA cases and 62% of RSA cases when all of the measures were considered.  

The prevalence of malpositioning in unrevised arthroplasties was not presented in this study.

Data such as that shown in graph A  (showing hypothetical values for unrevised shoulders) would suggest that malposition was not an important driver of revision.

On the other hand, data such as that shown in graph B would suggest that malposition was an important driver of revision.

This article did not provide data on the relationship of the degree of malposition to the rate of revision.

Data such as that shown in hypothetical graph C would suggest that the degree of malposition was tightly related to the revision rate.

Data such as that shown in hypothetical graph D would suggest that smaller degrees of malposition did not affect revision rate, whereas substantial degrees of malposition were clinically important.

What the literature does provide is evidence against a meaningful dose-response relationship. 

Below is a Forest plot of some key published studies relating glenoid component version to patient-reported clinical outcomes for aTSA and RSA. The effect sizes near zero with confidence intervals crossing the null line suggest the lack of a clinically meaningful dose-response relationship between glenoid component version and clinical outcome.

Below is a scatterplot showing the lack of a relationship between SANE and ASES scores and glenoid component version (data from Glenoid retroversion does not impact clinical outcomes or implant survivorship after total shoulder arthroplasty with minimal, noncorrective reaming).

Conclusion: A search of the currently available literature did not show a relationship between immediate postoperative radiographic measures of component position on one hand and clinically meaningful measures (such as patient-reported outcomes and revision rates) on the other. Such data will be important in demonstrating the potential clinical value of preoperative plan transfer technologies such as robotics, patient-specific instrumentation, navigation, and virtual/augmented reality. The thought that "continued improvements in component positioning technologies for both the glenoid and humeral implants are needed" will need to be supported by these analyses.

References

1. Checketts JX, Sanchez B, Norris G, Williamson TK, Hachadorian ME, Hsu JE, Schiffman CJ, Matsen FA III. Does postoperative glenoid component retroversion following anatomic total shoulder arthroplasty affect clinical outcomes? A systematic review and meta-analysis. J Shoulder Elbow Surg. 2026;35(5):1103–1116.

2. Sperling JW, Anderson MB, Jobin CM, Verborgt O, Duquin TR. Humeral and glenoid component malposition in patients requiring revision shoulder arthroplasty: a retrospective, cross-sectional study. J Shoulder Elbow Surg. 2025;34(8):1886–1896.

3. Service BC, Hsu JE, Somerson JS, Russ SM, Matsen FA III. Does postoperative glenoid retroversion affect the 2-year clinical and radiographic outcomes for total shoulder arthroplasty? Clin Orthop Relat Res. 2017;475(11):2726–2739.

4. Sheth MM, Mills ZD, Dasari SP, Whitson AJ, Matsen FA III, Hsu JE. Anatomic total shoulder arthroplasty for posteriorly eccentric and concentric osteoarthritis: a comparison at a minimum 5-year follow-up. J Shoulder Elbow Surg. 2025;34(2):473–483.

5. Matsen FA III, Whitson AJ, Somerson JS, Hsu JE. Anatomic total shoulder arthroplasty with all-polyethylene glenoid component for primary osteoarthritis with glenoid deficiencies. JB JS Open Access. 2020;5(4):e20.00002.

6. Grantham WJ, Dekker TJ, Lacheta L, Horan MP, Goldenberg BT, Elrick BP, et al. Total shoulder arthroplasty outcomes after noncorrective, concentric reaming of B2 glenoids. JSES Int. 2020;4(3):644–648.

7. Ma CB, Xiao W, Salesky M, Cheung E, Zhang AL, Feeley BT, et al. Do glenoid retroversion and humeral subluxation affect outcomes following total shoulder arthroplasty? JSES Int. 2020;4(3):649–656.

8. Rutledge JC, Dey Hazra RO, Geissbuhler AR, Yamaura K, Dey Hazra ME, Hanson JA, et al. Does glenoid version and its correction affect outcomes in anatomic shoulder arthroplasty? A systematic review. J Shoulder Elbow Surg. 2024;33(7):e384–e399.

9. Chalmers PN, Granger EK, Orvets ND, Patterson BM, Chamberlain AM, Keener JD, et al. Does prosthetic humeral articular surface positioning associate with outcome after total shoulder arthroplasty? J Shoulder Elbow Surg. 2018;27(5):863–870.

10. Werner BC, Creighton RA, Denard PJ, Lederman E, Romeo A, Griffin JW. Prosthetic humeral head center of rotation shift from ideal is associated with inferior clinical outcomes after anatomic total shoulder arthroplasty. Semin Arthroplasty JSES. 2021;31(4):668–676.

11. Varady NH, Bram JT, Chow J, Taylor SA, Dines JS, Fu MC, et al. Inconsistencies in measuring glenoid version in shoulder arthroplasty: a systematic review. J Shoulder Elbow Surg. 2025;34(2):639–649.

12. Terrier A, Ramondetti S, Merlini F, Pioletti DD, Farron A. Biomechanical consequences of humeral component malpositioning after anatomical total shoulder arthroplasty. J Shoulder Elbow Surg. 2010;19(8):1184–1190.

13. Franta AK, Lenters TR, Mounce D, Neradilek B, Matsen FA III. The complex characteristics of 282 unsatisfactory shoulder arthroplasties. J Shoulder Elbow Surg. 2007;16(5):555–562.

14. Sanchez-Sotelo J, Sperling JW, Rowland CM, Cofield RH. Instability after shoulder arthroplasty: results of surgical treatment. J Bone Joint Surg Am. 2003;85(4):622–631.

15. Burns DM, Frank T, Whyne CM, Henry PDG. Glenoid component positioning and guidance techniques in anatomic and reverse total shoulder arthroplasty: a systematic review and meta-analysis. Shoulder Elbow. 2019;11(2 Suppl):16–28.

16. Navarro RA, Chan PH, Prentice HA, Pearl M, Matsen FA III, McElvany MD. Use of preoperative CT scans and patient-specific instrumentation may not improve short-term adverse events after shoulder arthroplasty: results from a large integrated health-care system. JB JS Open Access. 2023;8(3):e22.00139.

17. Hsu JE, Hackett DJ Jr, Vo KV, Matsen FA III. What can be learned from an analysis of 215 glenoid component failures? J Shoulder Elbow Surg. 2018;27(3):478–486.

18. Walch G, Young AA, Boileau P, Loew M, Gazielly D, Molé D. Patterns of loosening of polyethylene keeled glenoid components after shoulder arthroplasty for primary osteoarthritis: results of a multicenter study with more than five years of follow-up. J Bone Joint Surg Am. 2012;94(2):145–150.

19. Harold RE, Sweeney PT, Torchia MT, Chamberlain AM, Keener JD. Total shoulder arthroplasty in patients with a B2 glenoid addressed with corrective reaming: mean 8-year follow-up. J Shoulder Elbow Surg. 2023;32(6 Suppl):S8–S16.

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