A Post-Market Clinical Evaluation of the ReUnion Reverse Shoulder Arthroplasty (RSA) System: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for A Post-Market Clinical Evaluation of the ReUnion Reverse Shoulder Arthroplasty (RSA) System (NCT03880955), a registered phase not stated study. The primary outcome is American Shoulder and Elbow Surgeons (ASES) Shoulder Score.

2. Clinical Question

The investigation concerned shoulder arthroplasty using the ReUnion RSA System. Its primary question was whether the device’s ASES Shoulder Score at 24 Months post-operative was non-inferior to selected literature controls. The registry record does not report the comparison values, a non-inferiority margin, or the analysis used to make that determination, so the stated question cannot be answered from the reported endpoint information alone.

3. Trial Design

This was a prospective, multicenter clinical investigation of the ReUnion RSA System. The registry record gives an enrollment of 102. Its brief summary anticipated a total of eighty subjects at approximately 4-7 sites; that statement is an anticipated enrollment description, not a report of how many sites actually enrolled subjects. The study status is TERMINATED. The listed start date is 2019-06-25, and the primary completion date is 2023-12-13. The reason for termination is not reported in the registry record.

The investigation was designed to follow the surgeon’s standard of care for joint arthroplasty subjects, with clinical evaluation on a regular ongoing basis or as needed if a subject became symptomatic in the treated joint. The primary endpoint was the ASES Shoulder Score at 24 Months post-operative. The record describes the primary endpoint objective as demonstrating non-inferiority to selected literature controls. It does not report a concurrent comparison arm, random allocation, or a detailed schedule of assessments beyond the stated endpoint timeframe.

The record lists safety outcomes involving device-related intra-operative and post-operative adverse events, as well as implant survivorship. The planned efficacy and safety outcomes do not by themselves show what was observed. The registry record does not report the protocol’s sample-size justification, the number of sites that participated, or the reasons for termination.

4. Participant Flow and Accounting

The registry reports how participants moved through each stage of the study. All counts below are exactly as posted; missing counts are not inferred from other stages.

Overall Study

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: 54 out of 102 Subjects had available data at 24mths.

5. Baseline Characteristics

The table reproduces the baseline characteristics posted in the registry, which describe the participants analysed at baseline and help show whether the randomized groups were comparable.

6. Primary Endpoint

The registry lists the primary outcome as American Shoulder and Elbow Surgeons (ASES) Shoulder Score, measured over 24 Months.

The primary endpoint was the American Shoulder and Elbow Surgeons Shoulder Score at 24 Months post-operative. This is a mixed measure for people with shoulder pathology regardless of diagnosis. It combines a pain visual analog scale with 10 functional questions, producing a score from 0 to 100. A score of 0 indicates a worse shoulder condition and 100 indicates a better shoulder condition.

The endpoint is intended to capture both pain and shoulder function rather than either dimension alone. A mean score summarizes the average measured score in the participants with data; the standard deviation describes how dispersed those scores are around the mean. These summaries can describe the observed group, but they do not alone establish whether the device met a non-inferiority objective. That assessment requires a defined comparison with the selected literature controls and a non-inferiority margin, neither of which is reported alongside an endpoint result in the registry record.

Available data at 24mths were reported for 54 out of 102 Subjects. The registry record does not report the corresponding ASES mean, standard deviation, or comparison estimate.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The primary measure is continuous: it can take values across a numerical scale, and the registry record describes its summary as a mean with standard deviation. The study’s endpoint is the ASES Shoulder Score, which combines pain and functional questions and ranges from 0 to 100. General statistical interpretation of such an endpoint depends on both the average score and the variability among measured participants.

What does a mean describe?

A mean is the arithmetic average of observed scores in the group being analyzed. It gives a compact description of the group’s central score, but does not show whether individual scores cluster closely around that average or vary substantially. The standard deviation describes that spread. Neither statistic identifies the reason for variation, and neither shows how representative the analyzed participants are of participants without endpoint data.

A mean and standard deviation are descriptive summaries, not a non-inferiority conclusion. A comparison requires a clearly specified reference value or comparator and an estimate of the difference under the chosen analysis. The registry record names selected literature controls as the comparator but does not report their ASES values or identify the literature sources used.

How is non-inferiority assessed?

In general, non-inferiority is evaluated against a prespecified margin. The margin defines how much worse the intervention could be relative to the comparator while still meeting the trial’s stated criterion. It should be set before outcome results are examined and justified for the clinical and statistical context. The registry record does not report a margin or its justification.

A confidence interval communicates uncertainty around an estimated comparison. For a non-inferiority analysis, its position relative to the margin is central: an estimate alone is not enough, because the interval indicates how much uncertainty remains. A narrow interval can provide more precise information than a wide interval, while an interval that crosses the non-inferiority boundary may leave the conclusion unresolved. These are general principles. The registry record does not report a comparison estimate, confidence interval, or test result for the ASES endpoint, so the criterion cannot be assessed from the posted results.

What can the endpoint availability tell readers?

The registry record states that 54 out of 102 Subjects had available data at 24mths. This is a measure of endpoint availability, not an outcome estimate. It does not show the scores of participants without available data, explain why those observations are absent, or establish whether missingness is related to the scores that would have been recorded. A complete-case mean, if one were calculated, would describe participants with observed data; interpretation for the enrolled study group would also depend on how missing data were handled and on assumptions about the missingness process.

Common approaches to missing data can produce different estimates when their assumptions differ. For example, an analysis that uses only observed outcomes does not recover unobserved scores. A model-based or imputation approach can incorporate additional information, but its conclusions depend on assumptions about the missing outcomes. These are general methodological points, not methods reported for this investigation. The missing-data method and any sensitivity analysis are not reported in the registry record.

What does the planning illustration mean?

The sample-size assumptions describe a planning illustration based on an observed effect, with a two-sided significance level of 0.05, equal allocation between the two arms, and a normal approximation. The stated effect to detect is a fraction of the observed effect. Such calculations illustrate the participant count associated with chosen assumptions; they do not describe the study’s observed statistical power. The record does not report the trial’s own sample-size justification, and the illustration should not be read as the trial’s original design rationale.

Planning calculations are sensitive to the assumed effect, variability, allocation, and statistical threshold. If the effect assumed for planning differs from the effect ultimately observed, the illustration will not describe the precision achieved by the study. No numeric planning values or observed ASES effect are reported in the registry record. Accordingly, no planning count can be connected to the endpoint result or treated as evidence of a successful or unsuccessful study.

Can the statistical analysis be reproduced?

The registry record does not report a detailed statistical analysis plan, the method for comparing the device with literature controls, covariate adjustments, or the handling of repeated or incomplete measurements. It lists 0 analyses. Without the analysis method and outcome summaries, readers cannot reproduce an estimate or assess its assumptions. The general statistical concepts above explain what such information would mean; they are not a description of analyses reported for the investigation.

10. Confidence Intervals for Each Arm

No two-arm comparison is shown for this trial, but each arm's mean can be given with a t-based 95% confidence interval computed from the posted mean, spread and number of participants.

R code and output

arm <- c("ReUnion RSA System")
n   <- c(54)
m   <- c(88.19)
sp  <- c(15.39)
sd  <- sp      # posted standard deviations
for (i in seq_along(n)) {
  se <- sd[i] / sqrt(n[i]); h <- qt(0.975, n[i] - 1) * se
  cat(sprintf("CARM|%s|%d|%.3f|%.3f|%.3f|%.3f\n", arm[i], n[i], m[i], sd[i], m[i] - h, m[i] + h))
}

CARM  ReUnion RSA System  54  88.190  15.390  83.989  92.391

11. Multiplicity, Missing Data and Analysis Populations

The registry record lists 4 outcome measures and 0 analyses. It names the ASES Shoulder Score as the primary endpoint and describes secondary outcomes for device-related intra-operative adverse events, device-related post-operative adverse events, and implant survivorship. The record does not report a multiplicity strategy, such as whether and how statistical error across multiple outcomes would be controlled. It also does not report which outcomes, if any, were included in formal hypothesis tests.

Multiplicity matters when several outcomes or comparisons are tested. In general, interpreting each test in isolation can overstate the strength of evidence across the full set of tests. Whether an adjustment is needed depends on the intended claims and analysis plan; no such plan or adjustment is reported in the registry record.

For the primary endpoint, available data at 24mths were reported for 54 out of 102 Subjects. Reasons for missing endpoint data, the method used to address missingness, and sensitivity analyses are not reported in the registry record. The record does not identify an analysis population or specify whether participants were analyzed according to enrollment, endpoint availability, or another rule. It is therefore not possible to determine how missing observations affected the reported statistical results, because the endpoint results and analysis details are not reported.

12. Safety Results

The registry reports serious adverse events as affected participants divided by participants at risk.

Deaths

Other (non-serious) adverse events

Participants with at least one non-serious event at or above the registry's 0% reporting threshold.

Most frequent non-serious adverse event terms

The adverse-event summary for the ReUnion RSA System group reports 102 subjects at risk for serious adverse events, with 0 serious adverse events, and 102 at risk for other adverse events, with 20 other adverse events. It also reports 1 death. These are separate categories in the registry summary and should not be combined into a single event count. The registry record does not report serious adverse-event terms, and it does not state whether the death was related to the device or procedure.

A reported count of 0 serious adverse events means no such events were recorded in this summary; it does not establish that the underlying risk is absent. Interpretation also depends on event definitions, follow-up, and attribution. The registry lists device-related intra-operative and post-operative event incidence as safety outcomes, but does not report separate incidence analyses or attribution details. The count of 20 other adverse events should not be treated as a count of device-related events without that information.

13. What the Result Does, and Does Not, Mean

The registry record establishes that NCT03880955 was a prospective, multicenter investigation of the ReUnion RSA System, with the ASES Shoulder Score at 24 Months as its primary endpoint and a stated non-inferiority objective against selected literature controls. It also records enrollment of 102 and endpoint data availability for 54 out of 102 Subjects at 24mths. These details describe the study and the extent of reported endpoint availability.

The posted information does not establish whether the device met the non-inferiority objective. The registry record does not report the ASES mean or standard deviation, the comparison estimate, a confidence interval, the non-inferiority margin, or the statistical analysis used. Without those elements, the result’s direction, magnitude, and precision cannot be evaluated.

The outcome availability statement does not explain why data were unavailable or how the missing data were handled. The record also does not report the analysis population or sensitivity analyses. These omissions limit assessment of how representative the observed endpoint data are and how stable any endpoint conclusion might be.

The safety summary reports 0 serious adverse events, 20 other adverse events, and 1 death in the ReUnion RSA System group. It does not establish device attribution for the death or the other adverse events. Counts alone do not show the timing, clinical context, or completeness of event capture.

These limits concern what can be concluded from the registry record. They are not evidence that the study’s unreported analyses had a particular result. The study status, TERMINATED, likewise does not establish the reason for termination or the direction of the endpoint findings.

14. Why This Trial Matters Statistically

This investigation raises a central statistical issue in device evaluations: a non-inferiority question needs more than an endpoint definition and an intended comparator. Interpretation depends on the comparison estimate, its uncertainty, and a clinically and statistically justified margin. When those elements are not reported, readers cannot distinguish a result that supports the stated criterion from one that remains inconclusive.

The choice of selected literature controls also matters. External controls can differ from the investigated participants in eligibility, measurement, follow-up, and clinical context. Those differences can complicate interpretation even when the endpoint name is the same. The registry record does not identify the literature sources or describe comparability, so the extent of this issue cannot be assessed for this investigation.

Endpoint availability is another important consideration. The record reports available ASES data for 54 out of 102 Subjects at 24mths, but gives no explanation of missingness or its handling. In general, incomplete outcome data can reduce precision and can also affect representativeness if the availability of measurements is related to outcomes or participant characteristics. This is a methodological possibility, not a finding about why data were unavailable in this study.

Finally, the safety outcomes and implant survivorship are clinically relevant dimensions distinct from the primary score. Their inclusion as planned outcomes does not provide their results. The record’s reported event counts, endpoint availability, and lack of reported analyses illustrate why registrations and posted results must be read separately: a stated objective describes the question, whereas numerical estimates and analysis details are needed to evaluate the evidence.

15. Limitations

• The posted summary statistics are the only data these results rest on; patient-level data, full protocols and statistical analysis plans are not available.
• Recalculated results are simple, unadjusted calculations from posted summaries. They do not replace the sponsor's prespecified analysis.

The most consequential limitation for statistical interpretation is that the registry record does not report the primary ASES outcome values or the non-inferiority analysis. The non-inferiority margin, comparator values, estimate, confidence interval, and inferential result are also not reported. The stated objective therefore cannot be evaluated from the posted endpoint information.

Available data at 24mths were reported for 54 out of 102 Subjects, but reasons for unavailable data and methods for handling missingness are not reported in the registry record. The analysis population and any sensitivity analyses are likewise not reported. These gaps prevent assessment of how missing endpoint information may affect the interpretation.

The comparator is described only as selected literature controls. The record does not identify the control sources or report whether their participants and outcome measurement were comparable with those in the investigation. It also does not report random allocation or a concurrent control group. These details are relevant to interpreting an external comparison but cannot be reconstructed from the record.

The record states TERMINATED but does not report the reason for termination. It does not provide the sample-size justification, a detailed statistical analysis plan, or a multiplicity approach. Although the summary gives adverse-event counts and a death count, it does not report attribution details or serious-event terms. Each of these limits constrains a different aspect of interpretation; none supplies evidence about the direction of an unreported treatment effect.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: A Post-Market Clinical Evaluation of the ReUnion Reverse Shoulder Arthroplasty (RSA) System — NCT03880955.
• Registry record last updated 2025-01-09; status last verified 2025-01.
• Results first posted 2025-01-09.
• Data retrieved from ClinicalTrials.gov on 2026-11-09.
• Group sizes, means, event counts and sponsor-reported p-values are reproduced as posted. Effect estimates, confidence intervals and p-values not attributed to the sponsor are independently calculated from the posted summary statistics.

19. Record Summary

NCT03880955 evaluated the ReUnion RSA System in a prospective, multicenter clinical investigation. The registry records enrollment of 102, a start date of 2019-06-25, primary completion on 2023-12-13, and status TERMINATED. The primary endpoint was the ASES Shoulder Score at 24 Months, with a stated non-inferiority objective relative to selected literature controls.

The record reports available endpoint data for 54 out of 102 Subjects at 24mths, but does not report the ASES results, non-inferiority margin, or analysis. The safety summary reports 0 serious adverse events, 20 other adverse events, and 1 death. The reason for termination, missing-data methods, analysis population, and detailed statistical plan are not reported in the registry record.