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. 2025 Oct 30;10(1):101401. doi: 10.1016/j.jseint.2025.10.003

Anatomic total shoulder arthroplasty for osteoarthritis in patients who are 75 years or older. An analysis of revision rates and patient-reported outcome using data from the Danish shoulder arthroplasty registry

Carl Johan Queitsch a,∗, Marc RK Nyring a, Andreas Falkenberg Nielsen a, Marie Louise Jensen a, Bo S Olsen a,b, Jeppe V Rasmussen a,b
PMCID: PMC12925865  PMID: 41737260

Abstract

Background

Anatomic total shoulder arthroplasty (aTSA) has been proven effective in the treatment of painful end-stage osteoarthritis in patients with intact rotator cuff function. However, elderly patients may have an increased risk of revision, especially when it comes to the risk of revision due to loosening, rotator cuff pathology and periprosthetic fracture. The aim of this study was to investigate revision rates and patient-reported outcomes after aTSA for osteoarthritis in patients who are 75 years or older. We hypothesized that revision rates and patient-reported outcomes were similar for patients aged 55-74 years and 75 years or older.

Methods

This is a registry-based cohort study with data from the Danish Shoulder Arthroplasty Registry. For analysis, 1,884 aTSAs used for osteoarthritis between January 1, 2012, and December 31, 2019, were included. Patients were divided into 2 age groups: 55-74 years and 75 years or older. The Kaplan–Meier method was used to estimate unadjusted cumulative revision rates and a multivariate Cox regression model was used to determine hazard ratios. A multivariable linear regression model was used to compare the Western Ontario Osteoarthritis of the Shoulder Index (WOOS) 1 year postoperatively.

Results

There were 34 (2.5%) patients in the middle-aged group and 8 (1.6%) patients in the older age group who had revision surgery. The hazard ratio for revision was 0.67 for the older age group compared to the middle-aged group (95% confidence interval [CI] 0.31-1.47, P = .32). The unadjusted 2-year and 5-year cumulative revision rates were 2.3% (95% CI 1.4-3.2) and 3.6% (95% CI 2.3-4.9) in the middle-aged group and 1.7% (95% CI 0.4-3.0) and 2.2% (95% CI 0.6-3.8) in the older age group. The mean WOOS score was 84 (standard deviation = 20) in the middle-aged group and 85 (standard deviation = 20) in the older age group. The difference in WOOS between the 2 groups was 1.2 points (95% CI −1.5 to 3.8, P = .40).

Conclusion

We found low short-term revision rates and good patient-reported outcomes for both middle-aged and older patients treated for osteoarthritis using aTSA. The small differences in WOOS between the 2 age groups were not clinically relevant nor statistically significant. aTSA provides good and reliable outcomes in elderly patients with end-stage osteoarthritis, and age alone should not be a reason for opting out aTSA.

Keywords: Shoulder, Arthroplasty, Osteoarthritis, Rotator cuff, Elderly, Anatomic total shoulder arthroplasty, Revision rates

The incidence of shoulder arthroplasty for osteoarthritis and cuff arthropathy has increased during the last several decades.42 This might be related to a growing elderly population with high functional demands, better and more reliable outcomes of shoulder arthroplasty for these indications and the use of reverse shoulder arthroplasty (rTSA) for cuff-tear arthropathy and osteoarthritis with rotator cuff pathology or glenoid bone loss.

It is well known that poor health,22 osteopenia9,40 and rotator cuff pathology15 are associated with increased age. This might increase the risk of revision after anatomic total shoulder arthroplasty (aTSA) especially when it comes to the risk of revision due to aseptic loosening, rotator cuff pathology, and periprosthetic fracture.4,28 Therefore, rTSA is preferred by many clinicians when treating elderly patients, regardless of the rotator cuff function at the time of surgery.3,17,40

Nevertheless, studies have shown unique complications related specifically to the rTSA, including acromial and scapular spine fractures and inferior scapular notching. Additionally, the functional outcome might be inferior to aTSA.5,40

Previous studies have examined the revision rates of aTSA and rTSA in elderly populations,7,11,40 but revision rate alone does not necessarily reflect the effect of the arthroplasty. For elderly patients, surgeons might hesitate to revise because of comorbidity, lower functional demands or because the revision procedure can be technically demanding. Other studies have reported the functional outcome of aTSA in the elderly population, but these studies are too small to provide safe estimates of both functional outcome and risk of revision.7,11,17,40

The aim of this study was to investigate the revision rates and patient-reported outcome of aTSA for osteoarthritis in patients who are 75 years or older. Our hypothesis was that revision rates and patient-reported outcomes are similar for patients aged 55-74 years, and patients aged 75 years or older, when treated with aTSA for osteoarthritis.

Materials and methods

Study design

This is a registry-based cohort study with data from the Danish Shoulder Arthroplasty Registry (DSR). The study was conducted and reported in accordance with the REporting of studies Conducted using Observational Routinely collected health Data statement (RECORD).43

Data source

The DSR was founded in 2004 on the initiative of the Danish Society for Shoulder and Elbow surgery. It is financed by the Danish health-care authorities and is independent of commercial interests. Reporting became mandatory in 2006 primary and revision procedures. The completeness of reporting is 94% for primary arthroplasties31 and 87% for revision arthroplasties.35 The completeness of reporting is monitored using data from the Danish National Patient Registry as the reference. Surgeons use an online platform to report data related to the patient and the surgical procedure with documented accurate reporting of key variables.31

Setting and participants

From January 1, 2012, to December 31, 2019, a total of 2,095 aTSAs for osteoarthritis were reported to the DSR (Fig. 1). We excluded patients with other indications that osteoarthritis (n = 4,775) and patients who were treated with rTSA or hemiarthroplasty (n = 1,593). As previous studies from the DSR have shown inferior results for young patients, 175 aTSAs in patients younger than 55 years were excluded.32 Furthermore, 36 aTSAs with a metal-backed glenoid component were excluded due to a documented high revision rate.27 Thus, 1,884 arthroplasties were included in the study (Fig. 2). The patients were divided into 2 age groups: 55-74 years and 75 years or older at the time of surgery. These age groups are referred to as the middle-aged group and the older age group.

Figure 1.

Figure 1

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Number of aTSAs reported to the DSR per year from 2012-2019 according to age group. aTSA, anatomic total shoulder arthroplasty; DSR, Danish Shoulder Arthroplasty Registry.

Figure 2.

Figure 2

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STROBE flowchart showing inclusion and exclusion of patients. DSR, Danish Shoulder Arthroplasty Registry; WOOS, Western Ontario Osteoarthritis of the Shoulder index; STROBE, Strengthening the Reporting of Observational Studies in Epidemiology.

Outcome

Revision

Revision was defined by the DSR as an operation in which 1 or more components were exchanged, removed, or added.34 Reason for revision and time to revision were recorded. Time at risk was defined as the time from the primary procedure to the revision procedure, death, or the end of the study period. The mean follow-up time was 36 months (range 0.3-96 months).

Primary and revision procedures were linked using the Danish central personal registration number.32 Although it violates the assumption of independence, inclusion of bilateral arthroplasties has been shown to have little practical consequences in registry-based studies.38 Bilateral arthroplasties were therefore included.

Patient-reported outcome

The DSR uses a Danish version33 of the Western Ontario Osteoarthritis of the Shoulder Index (WOOS) as patient-reported outcome measure.10 Administrative personnel located at the DSR facilitate collecting of the questionnaire for each patient 1 year after the primary procedure.33 Within the first year of surgery, 14 patients died and 15 patients underwent revision. The WOOS questionnaire was sent to 1,855 patients of whom 1,164 returned a complete questionnaire. Only the completed questionnaires were included in the analyses of WOOS scores. The minimal clinically important difference (MCID) for WOOS in patients treated with an aTSA has been determined as 12.3 points.25 MCID was developed to track changes in patient-specific outcome on an individual level, not to evaluate differences on a group-to-group basis.8,23 Nevertheless, as there is presently no better alternative, we regarded a difference of 12.3 as being clinically relevant. Clinical failure is arbitrary defined by the DSR as a WOOS score below 50.35

Statistical methods

Continuous data did not follow the assumption of normal distribution. Thus, time to revision was reported with median and interquartile range (IQR), while WOOS was reported with mean and standard deviation (SD) as this can be accepted in large datasets without major outliers.21 Categorical data were reported with numbers and percentages. Kaplan–Meier regression method was used to estimate the unadjusted cumulative revision rates. Comparisons between the 2 age groups were assessed with the log-rank test. The multivariate Cox regression was used to determine hazard ratios (HR) between the 2 age groups. The proportional hazards assumption was checked visually by inspecting if the cumulative revision rates crossed at any given time in the Kaplan–Meier illustration, by calculating Schoenfeld's residuals, and with log minus log plots. The revision curves crossed within the first 2 years of the follow-up period (Fig. 3) and the log-minus-plots intersected. The Schoenfeld residuals and the global P value were not statistically significant.18 Mortality is a competing risk in statistical analyses regarding revision rates following arthroplasty surgery. Nonetheless, Lie et al have shown that Cox regression analysis is still preferable for time-dependent analysis of implant survival.20 A univariate and multivariable linear regression model was used to compare the WOOS scores between the 2 age groups. A univariate and multivariable logistic regression model was used to determine odds ratios of clinical failure (e.g. WOOS <50) between the 2 groups. Sex was included in the multi variate Cox regression model, in the multivariable linear regression model and in the logistic regression model. A 2-tailed P value <.05 between the 2 study groups was considered statistically significant. The statistical programs SPSS (version 29.0.1.0; IBM Corp, Armonk, NY, USA) and R Studio (version 4.4.1; Posit, Boston, MA, USA) were used for the analyses.16,30

Figure 3.

Figure 3

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Unadjusted cumulative revision rates according to age group.

Results

Revision

There were 1,367 arthroplasties in the middle-aged group of which 34 (2.5%) arthroplasties were revised and 517 implants in the older age group of which 8 (1.6%) were revised. Median time to revision was 17 months (IQR 8.4-28) in the middle-aged group and 13 months (IQR 5.1-20) in the older age group. The proportion of women was higher in the older age group (80%) than in the middle-aged group (61%). During the study period, 35 (2.6%) patients in the middle-aged group and 48 (9.3%) patients in the older age group died. The HR for revision was 0.67 in the older age group with the middle-aged group as reference (95% CI 0.31-1.47, P = .32).

The unadjusted overall cumulative revision rate for all patients was 6.1% (95% CI 0.4-12). The unadjusted 2-year and 5-year cumulative revision rates were 2.3% (95% CI 1.4-3.2) and 3.6% (95% CI 2.3-4.9) in the middle-aged group and 1.7% (95% CI 0.4-3.0) and 2.2% (95% CI 0.6-3.8) in the older age group (Fig. 3). Using a log-rank test, a nonsignificant difference was determined (P = .30). The most common reason for revision was instability/rotator cuff pathology in both age groups (Table I).

Table I.

Reasons for revision.

Reason for revision Age 55-74 (yrs) (N = 1,367) Age ≥75 (yrs) (N = 517)
Suspected or manifest infection 5 (0.4) 0 (0.0)
Periprosthetic fracture <3 (<0.2)∗ 0 (0.0)
Instability/rotator cuff pathology 11 (0.8) 4 (0.8)
Loosening of any component 8 (0.6) <3 (<0.6)∗
Other 8 (0.6) <3 (<0.6)∗
Not specified <3 (<0.2)∗ 0 (0.0)
Overall 34 (2.5) 8 (1.6)
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Parenthesis contains percentage of all arthroplasties in that age group. "Other" includes wear of the polyethylene glenoid component. Several reasons for revision had cell counts below 3, which required anonymization and are marked with an asterisk.

Patient-reported outcome

Before the 1-year follow-up, 14 patients died and 15 patients were revised. Thus, 1855 WOOS questionnaires were sent to patients. In the older age group, 307 (61%) patients and 857 (64%) patients in the middle-aged group returned a complete questionnaire resulting in an overall response rate of 63% for the entire population (Fig. 2).

The mean WOOS score was 84 (SD = 20) in the middle-aged group and 85 (SD = 20) in the older age group. The difference in WOOS score between the 2 groups was small in the univariate linear regression model (difference 0.9, 95% CI -1.7 to 3.6, P = .48) and in the multivariable linear regression model (difference 1.2, 95% CI -1.5 to 3.8, P = .40). A WOOS score below 50 as a measure of clinical failure was reported in 80 (9.3%) patients in the middle-aged group and 24 (7.8%) patients in the older age group. The risk of clinical failure in the older age group was 0.8 (95% CI 0.5-1.3, P = .42) in the univariate logistic regression model and 0.9 (95% CI 0.5-1.4, P = .50) in the multivariable regression model with the middle-aged group as the reference. The distribution of the WOOS score was similar across the 2 age groups (Fig. 4).

Figure 4.

Figure 4

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WOOS distribution in each age group (55-74 and ≥ 75). Dashed line is the mean value (84 and 85, respectively), and the dotted line is the median value (92 and 93, respectively). WOOS, Western Ontario Osteoarthritis of the Shoulder index.

Discussion

Important findings

We found low revision rates for both older and middle-aged patients treated for osteoarthritis using aTSA with no statistically significant differences between the 2 groups in the Kaplan–Meier curves or in the Cox regression model. Furthermore, the WOOS score indicated similar good results for both middle-aged and older patients.

Risk of revision

We found no statistically significant difference in risk of revision between the 2 age groups. This indicates that higher age is not associated with an increased risk of revision, but because of the limited sample size, safe estimates cannot be made. Thus, we cannot make any safe conclusions other than the HR for revision for older patients with 95% probability is between 0.31 and 1.47 with middle-aged patients as reference.

Previous studies have shown varying revision rates following aTSA which, in recent years, seems to improve. We found low revision rates across both age groups which corresponds well to previous studies.7,11,17,26,40

A study conducted by Newman et al found that patients between 80 and 89 years old had an increased risk of infection compared with younger patients, but they did not include revision rates nor did they differentiate between aTSA and rTSA.24 rTSA is associated with a higher risk of revision due to periprosthetic joint infection and their findings might be influenced by a high proportion of rTSA in the elderly population.3,17,40 In our study, the risk of revision due to periprosthetic joint infection was low for both the middle-aged group and the older age group (Table I).

Loosening of any component was the second-most frequent reason for revision in both age groups. Other studies have reported aseptic loosening, most commonly in the glenoid component, as a frequent reason for revision—often occurring after several years.13,19 Aseptic loosening in the short-term, on the other hand, might be related to low-grade infection.12 In our study, surgeons could, potentially, have reported the reason for revision as loosening before relevant perioperative microbiological testing was available.

Instability/rotator cuff pathology was the most frequent reason for revision in both age groups which correlates well with other studies showing that rotator cuff tear is a common cause of revision after aTSA.11,37 Su et al states it is vital to unanimously report rotator cuff failure correctly as the revision rates can vary greatly between studies.40 Some studies report radiographic evidence of superior humeral head migration as the sole definition of rotator cuff tear following total shoulder arthroplasty regardless of patient symptoms. In DSR, the surgeon defines what constitutes his or her reason for revision as the DSR does not clearly define what constitutes reasons for revision. It is presumed to be based on preoperative imaging (including ultrasound), clinical function (strength and lag sign test) and, ultimately, a perioperative assessment.

Patient-reported outcome (Western Ontario Osteoarthritis of the Shoulder Index)

We found that the middle-aged group and the older age group had high and nearly identical WOOS scores with no detectable differences in the multivariable linear regression model. Similar findings have been reported by other studies.7,40 Wright et al conducted a study examining 135 patients aged 70 or older undergoing either rTSA or aTSA.41 They found a mean WOOS score of 86. Another study conducted by Nyring et al examining 49 patients of all ages following aTSA found a mean WOOS score of 84, 2 years postoperatively. The difference between the preoperative and postoperative assessment was 46.1 and 87% of the patients had an improvement in WOOS which exceeded the MCID of 12.3 points.26 To our knowledge, our study was the first study to include WOOS in a linear regression model to analyze a large cohort of middle-aged and older patients. We used the WOOS to illustrate that a high proportion of patients have a high WOOS score and that only few patients experienced a clinical failure which is arbitrarily defined in the DSR as a score below 50 (Fig. 4).

Potential disadvantages of using revision rate as a measurement of outcome, especially in the elderly

Debernadis et al highlighted that revision rates can be affected by the surgeon's preference to perform surgery and the patient's inclination to disclose symptoms or to agree to having surgery performed.7 This could theoretically result in falsely low revision rates especially for older patients. It is also worth noting that low revision rates do not equal an overall good clinical outcome. Some patients are never revised due to technical demands or comorbidity.32 Patients who are treated with shoulder arthroplasty for proximal humeral fractures experience low revision rates but simultaneously poor functional and patient-reported outcomes.1,2 Thus, using revision rates as the only outcome may lead to false conclusions. The major findings of this study are, therefore, not only the low revision rates but also the good patient-reported outcomes, indicating that aTSA can successfully be used in the treatment of elderly patients with end-stage osteoarthritis.

Anatomic and reverse total shoulder arthroplasty for osteoarthritis

Several studies have compared revision rates between aTSA and rTSA in the elderly in systematic reviews.7,11,17,40 One systematic review40 reported that aTSA was superior to the rTSA in terms of functional outcomes in patients with an intact rotator cuff although the patient satisfaction was comparably high and revision rates comparably low. Additionally, Kim et al analyzed a total of 318 patients from 6 studies in a systematic review and meta-analysis.17 They included patients of all ages and found 10 (3.1%) patients who had revision surgery with mid-term follow-ups (>2 years). The number of patients and revisions was too small to make conclusions regarding the risk of revision, but aTSA was associated with a better range of motion than rTSA. Another systematic review11 examining revision rates between rTSA and aTSA in patients aged 70 years or older without a full-thickness rotator cuff tear found higher revision rates using the aTSA. The reason for this is unknown, but the authors hypothesized that surgeons might hesitate to revise a rTSA as this can be more technically challenging than revising an aTSA. We have not been able to identify any randomized, controlled trials comparing the outcomes of aTSA and rTSA for glenohumeral osteoarthritis.

Methodological considerations

Mortality is a competing risk in implant survival analysis. The consequences are an overestimated revision risk – particularly in the older age group.36 In our study, the mortality rate was 2.6% for the middle-aged group and 9.3% in the older age group. The differences in mortality rates are important to keep in mind when the risk of competing risk is discussed. A study has shown that it might be helpful to use a competing risk modeling approach. The authors examined potential differences of competing risk and noncompeting risk methods using arthroplasty data from the Australian Orthopaedic Association National Joint Replacement Registry. In the most extreme instances, the absolute difference in predicted 10-year revision risk was 1.8% which may be of no clinical significance.6 Additionally, Lie et al concludes that adding death as a competing risk will always attenuate the probability of revision and does not correct for dependency between patient death and revision.20

The revision rates were 1.6% for the older age group and 2.5% for the middle-aged group, which appear relatively low. When the completeness of reporting of revision arthroplasty is not 100%, an underestimation of the true revision rate is inevitable. We fully acknowledge that this leads to an underestimation of the revision rate. However, as only 13% are missing, we consider the impact on the interpretation of the revision rates to be limited. As there is nothing to suggest systematic differences in the completeness of reporting of revision arthroplasty between the 2 groups, the underreporting is unlikely to influence the results of the Cox regression analysis. Another reason for the relatively low revision rate can be the short follow-up time—up to 8 years. Common reasons for revision of aTSA are aseptic loosening of the glenoid component and rotator cuff pathology which often occur with a longer follow-up time. Therefore, we expect that revision rates will increase in the coming years as data with longer follow-up become available.

We did not include a preoperative WOOS score and we did not have mid-term or long-term follow-ups as this was not collected by DSR. In this study, an overall response rate of 63% of the WOOS was obtained. A higher completion rate of the WOOS could affect the results of this study although non-responders of the WOOS do not appear to bias the overall results after shoulder replacement.29

Residual confounding remains a challenge in registry-based studies.14 As an example, we would expect older patients to have a higher risk of having rotator cuff pathology as a result of atrophy, fatty tissue infiltration and poor quality of tendons.39 The DSR does not collect detailed information regarding rotator cuff status preoperatively and consequently, we were not able to adjust our data accordingly.

Conclusion

We found low short-term revision rates and good patient-reported outcomes for both older and middle-aged patients treated for osteoarthritis using aTSA. The small differences between the 2 age groups were not clinically relevant or statistically significant.

aTSA provides good and reliable outcomes in elderly patients with end-stage osteoarthritis, and age alone should not be a reason for opting out of aTSA.

Disclaimers:

Funding: No funding was disclosed by the authors.

Conflicts of interest: Dr. Marie Louise Jensen reports receiving research support from DePuy/Synthes for a study on lateralization of reverse shoulder arthroplasty. Dr. Bo S. Olsen reports receiving research support from DePuy/Synthes for a study on lateralization of reverse shoulder arthroplasty; receves institutional support from Johnson & Johnson and Zimmer/Biomet; receives speaker fee from Swemac; and is a member of the board of the Danish Shoulder Arthroplasty Registry. Dr. Jeppe V. Rasmussen reports receiving research support from DePuy/Synthes for a study on lateralization of reverse shoulder arthroplasty; receives institutional support from Johnson & Johnson and Zimmer/Biomet; is a member of the board of the Danish Shoulder Arthroplasty Registry; and treasurer at the Danish Orthopedic Society. All of the declared is without relation to the submitted work. The other authors, their immediate families, and any research foundation with which they are affiliated have not received any financial payments or other benefits from any commercial entity related to the subject of this article.

Footnotes

Permission to conduct this study was provided by the Center for Regional Development in the Capital Region of Denmark with the study number: P-2023-274.

References

  • 1.Amundsen A., Brorson S., Olsen B.S., Rasmussen J.V. Ten-year follow-up of stemmed hemiarthroplasty for acute proximal humeral fractures. Bone Joint J. 2021;103-B:1063–1069. doi: 10.1302/0301-620X.103B6.BJJ-2020-1753.R1. [DOI] [PubMed] [Google Scholar]
  • 2.Amundsen A., Rasmussen J.V., Olsen B.S., Brorson S. Low revision rate despite poor functional outcome after stemmed hemiarthroplasty for acute proximal humeral fractures: 2,750 cases reported to the Danish Shoulder Arthroplasty Registry. Acta Orthop. 2019;90:196–201. doi: 10.1080/17453674.2019.1597491. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 3.Barret H., Bonnevialle N., Azoulay V., Baron-Trocellier T., Mansat P. Short-stem uncemented anatomical shoulder replacement for osteoarthritis in patients older than 70 years: is it appropriate? JSES Int. 2021;5:656–662. doi: 10.1016/j.jseint.2021.02.014. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 4.Casp A.J., Montgomery S.R., Cancienne J.M., Brockmeier S.F., Werner B.C. Osteoporosis and implant-related complications after anatomic and reverse total shoulder arthroplasty. J Am Acad Orthop Surg. 2020;28:121–127. doi: 10.5435/JAAOS-D-18-00537. [DOI] [PubMed] [Google Scholar]
  • 5.Cassidy J.T., Paszicsnyek A., Ernstbrunner L., Ek E.T. Acromial and scapular spine fractures following reverse total shoulder arthroplasty—A systematic review of fixation constructs and techniques. J Clin Med. 2022;11:7025. doi: 10.3390/jcm11237025. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 6.Cuthbert A.R., Graves S.E., Giles L.C., Glonek G., Pratt N. What is the effect of using a competing-risks estimator when predicting survivorship after joint arthroplasty: a comparison of approaches to survivorship estimation in a large registry. Clin Orthop. 2021;479:392–403. doi: 10.1097/CORR.0000000000001533. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 7.DeBernardis D.A., Zhang T., Duong A., Fleckenstein C.M., Almasri M., Hasan S.S. Total shoulder arthroplasty in patients aged 80 years and older: a systematic review. J Shoulder Elbow Surg. 2023;33:425–434. doi: 10.1016/j.jse.2023.08.003. [DOI] [PubMed] [Google Scholar]
  • 8.Dekker J., de Boer M., Ostelo R. Minimal important change and difference in health outcome: an overview of approaches, concepts, and methods. Osteoarthritis Cartilage. 2024;32:8–17. doi: 10.1016/j.joca.2023.09.002. [DOI] [PubMed] [Google Scholar]
  • 9.Delsmann M.M., Schmidt C., Mühlenfeld M., Jandl N.M., Boese C.K., Beil F.T., et al. Prevalence of osteoporosis and osteopenia in elderly patients scheduled for total knee arthroplasty. Arch Orthop Trauma Surg. 2022;142:3957–3964. doi: 10.1007/s00402-021-04297-x. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 10.Demir Y., Sjöberg H., Stark A., Salomonsson B. Western Ontario Osteoarthritis of the Shoulder Index (WOOS) - a validation for use in proximal humerus fractures treated with arthroplasty. BMC Musculoskelet Disord. 2023;24:450. doi: 10.1186/s12891-023-06578-5. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 11.Dragonas C.G., Mamarelis G., Dott C., Waseem S., Bajracharya A., Leivadiotou D. Anatomic total shoulder arthroplasty versus reverse total shoulder arthroplasty in patients aged over 70 without a full-thickness Rotator Cuff Tear: a systematic review and Meta-Analysis. J Shoulder Elb Arthroplasty. 2023;7 doi: 10.1177/24715492231206685. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 12.Falstie-Jensen T., Lange J., Daugaard H., Sørensen A.K.B., Ovesen J., Søballe K., et al. Unexpected positive cultures after revision shoulder arthroplasty: does it affect outcome? J Shoulder Elbow Surg. 2021;30:1299–1308. doi: 10.1016/j.jse.2020.12.014. [DOI] [PubMed] [Google Scholar]
  • 13.Gauci M.-O., Caubere A., Bronsard N., Jacquot A., Julien B., Gonzalez J.-F. Anatomical Total Shoulder Arthroplasty with Keeled glenoids in patients under 60 years at 10 years minimum: which risk factors of failure are still valid at long term follow-up? J Shoulder Elbow Surg. 2025;34:e611–e620. doi: 10.1016/j.jse.2024.11.039. [DOI] [PubMed] [Google Scholar]
  • 14.Grant A., Colman I., Freeman E.E. Impact of the improper adjustment for Age in research on age-related macular degeneration: an example using data from the Canadian longitudinal Study on aging. Ophthalmic Epidemiol. 2021;28:86–89. doi: 10.1080/09286586.2020.1853179. [DOI] [PubMed] [Google Scholar]
  • 15.Grusky A.Z., Giri A., O’Hanlon D., Jain N.B. The relationship of aging and smoking with Rotator Cuff disease: a systematic review and meta-analysis. Am J Phys Med Rehabil. 2022;101:331–340. doi: 10.1097/PHM.0000000000001820. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 16.IBM Corp . 2023. IBM SPSS statistics for windows. IBM Company: Armonk, NY. [Google Scholar]
  • 17.Kim H., Kim C.-H., Kim M., Lee W., Jeon I.-H., Lee K.W., et al. Is reverse total shoulder arthroplasty (rTSA) more advantageous than anatomic TSA (aTSA) for osteoarthritis with intact cuff tendon? A systematic review and meta-analysis. J Orthop Traumatol. 2022;23:3. doi: 10.1186/s10195-022-00625-y. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 18.Kuitunen I., Ponkilainen V.T., Uimonen M.M., Eskelinen A., Reito A. Testing the proportional hazards assumption in cox regression and dealing with possible non-proportionality in total joint arthroplasty research: methodological perspectives and review. BMC Musculoskelet Disord. 2021;22:489. doi: 10.1186/s12891-021-04379-2. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 19.Li T., Duey A.H., White C.A., Pujari A., Patel A.V., Zaidat B., et al. Evaluating the effects of age on the long-term functional outcomes following anatomic total shoulder arthroplasty. Clin Shoulder Elb. 2023;26:231–237. doi: 10.5397/cise.2023.00409. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 20.Lie S.A., Fenstad A.M., Lygre S.H.L., Kroken G., Dybvik E., Gjertsen J.-E., et al. Kaplan-Meier and cox regression are preferable for the analysis of time to revision of joint arthroplasty: Thirty-One years of Follow-up for cemented and uncemented THAs inserted from 1987 to 2000 in the Norwegian arthroplasty register. JB JS Open Access. 2022;7 doi: 10.2106/JBJS.OA.21.00108. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 21.Lumley T., Diehr P., Emerson S., Chen L. The importance of the normality assumption in large public health data sets. Annu Rev Public Health. 2002;23:151–169. doi: 10.1146/annurev.publhealth.23.100901.140546. [DOI] [PubMed] [Google Scholar]
  • 22.Marengoni A., Rizzuto D., Wang H.-X., Winblad B., Fratiglioni L. Patterns of chronic multimorbidity in the elderly population. J Am Geriatr Soc. 2009;57:225–230. doi: 10.1111/j.1532-5415.2008.02109.x. [DOI] [PubMed] [Google Scholar]
  • 23.Mouelhi Y., Jouve E., Castelli C., Gentile S. How is the minimal clinically important difference established in health-related quality of life instruments? Review of anchors and methods. Health Qual Life Outcomes. 2020;18:136. doi: 10.1186/s12955-020-01344-w. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 24.Newman J.M., Stroud S.G., Yang A., Sodhi N., Dixit A., Doran J.P., et al. Total shoulder arthroplasty in octogenarians: is there a higher risk of adverse outcomes? J Orthop. 2018;15:671–675. doi: 10.1016/j.jor.2018.05.035. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 25.Nyring M.R.K., Olsen B.S., Amundsen A., Rasmussen J.V. Minimal Clinically Important Differences (MCID) for the Western Ontario osteoarthritis of the shoulder index (WOOS) and the Oxford Shoulder Score (OSS) Patient Relat Outcome Meas. 2021;12:299–306. doi: 10.2147/PROM.S316920. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 26.Nyring M.R.K., Olsen B.S., Amundsen A., Rasmussen J.V. High rate of clinically relevant improvement following anatomical total shoulder arthroplasty for glenohumeral osteoarthritis. World J Orthop. 2024;15:156–162. doi: 10.5312/wjo.v15.i2.156. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 27.Nyring M.R.K., Olsen B.S., Jensen S.L., Rasmussen J.V. High revision rate of metal-backed glenoid component and impact on the overall revision rate of stemless total shoulder arthroplasty: a cohort study from the Danish Shoulder Arthroplasty Registry. Acta Orthop. 2024;95:386–391. doi: 10.2340/17453674.2024.41014. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 28.Parada S.A., Flurin P.-H., Wright T.W., Zuckerman J.D., Elwell J.A., Roche C.P., et al. Comparison of complication types and rates associated with anatomic and reverse total shoulder arthroplasty. J Shoulder Elbow Surg. 2021;30:811–818. doi: 10.1016/j.jse.2020.07.028. [DOI] [PubMed] [Google Scholar]
  • 29.Polk A., Rasmussen J.V., Brorson S., Olsen B.S. Reliability of patient-reported functional outcome in a joint replacement registry. A comparison of primary responders and non-responders in the Danish Shoulder Arthroplasty Registry. Acta Orthop. 2013;84:12–17. doi: 10.3109/17453674.2013.765622. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 30.R Core Team R: a Language and environment for statistical computing [Internet] 2024. https://www.R-project.org/ Available at: Accessed November 26, 2025.
  • 31.Rasmussen J.V., El-Galaly A., Thillemann T.M., Jensen S.L. High completeness and accurate reporting of key variables make data from the Danish shoulder arthroplasty registry a valuable source of information. Clin Epidemiol. 2021;13:141–148. doi: 10.2147/CLEP.S291972. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 32.Rasmussen J.V., Hole R., Metlie T., Brorson S., Äärimaa V., Demir Y., et al. Anatomical total shoulder arthroplasty used for glenohumeral osteoarthritis has higher survival rates than hemiarthroplasty: a Nordic registry-based study. Osteoarthritis Cartilage. 2018;26:659–665. doi: 10.1016/j.joca.2018.02.896. [DOI] [PubMed] [Google Scholar]
  • 33.Rasmussen J.V., Jakobsen J., Olsen B.S., Brorson S. Translation and validation of the Western Ontario Osteoarthritis of the Shoulder (WOOS) index - the Danish version. Patient Relat Outcome Meas. 2013;4:49–54. doi: 10.2147/PROM.S50976. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 34.Rasmussen J.V., Olsen B.S., Fevang B.-T.S., Furnes O., Skytta E.T., Rahme H., et al. A review of national shoulder and elbow joint replacement registries. J Shoulder Elbow Surg. 2012 Oct;21:1328–1335. doi: 10.1016/j.jse.2012.03.004. [DOI] [PubMed] [Google Scholar]
  • 35.Regionernes Kliniske Kvalitetsudviklingsprogram (RKKP) Dansk Skulderalloplastik Register (DSR) årsrapport 2023 [Internet] 2023. https://www.sundk.dk/media/bjk4nzfc/f8809a85a187497db2d9189fb2249b8d.pdf Available at: Accessed November 26, 2025.
  • 36.Sayers A., Evans J.T., Whitehouse M.R., Blom A.W. Are competing risks models appropriate to describe implant failure? Acta Orthop. 2018;89:256–258. doi: 10.1080/17453674.2018.1444876. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 37.Schoch B.S., Tams C., Eichinger J., Wright T.W., King J.J., Friedman R.J. Anatomic total shoulder arthroplasty after healed rotator cuff repair: a matched cohort. J Shoulder Elbow Surg. 2020;29:2221–2228. doi: 10.1016/j.jse.2020.03.029. [DOI] [PubMed] [Google Scholar]
  • 38.Smith J.-R.H., Houck D.A., Hart J.A., Bravman J.T., Frank R.M., Vidal A.F., et al. Bilateral total shoulder arthroplasty: a systematic review of clinical outcomes. Shoulder Elb. 2021;13:402–415. doi: 10.1177/1758573220916822. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 39.Son J.H., Seo Z.W., Choi W., Lee Y.-Y., Kang S.-W., Lee C.-H. Etiologic factors of Rotator Cuff Disease in elderly: modifiable factors in addition to known demographic factors. Int J Environ Res Public Health. 2022;19:3715. doi: 10.3390/ijerph19063715. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 40.Su F., Nuthalapati P., Feeley B.T., Lansdown D.A. Outcomes of anatomic and reverse total shoulder arthroplasty in patients over the age of 70: a systematic review. JSES Rev Rep Tech. 2023;3:181–188. doi: 10.1016/j.xrrt.2023.02.003. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 41.Wright M.A., Keener J.D., Chamberlain A.M. Comparison of clinical outcomes after anatomic total shoulder arthroplasty and reverse shoulder arthroplasty in patients 70 years and older with glenohumeral osteoarthritis and an intact rotator cuff. J Am Acad Orthop Surg. 2020;28 doi: 10.5435/JAAOS-D-19-00166. [DOI] [PubMed] [Google Scholar]
  • 42.dsr-evidensrapport-version-5.0-final.pdf [Internet] https://www.rkkp.dk/siteassets/de-kliniske-kvalitetsdatabaser/databaser/skulderalloplastik/dsr-evidensrapport-version-5.0-final.pdf Available at:
  • 43.RECORD Checklist.pdf [Internet] https://www.record-statement.org/Files/checklist/RECORD20Checklist.pdf Available from:

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