Multicenter Clinical Observation PROMOS®: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Multicenter Clinical Observation PROMOS® (NCT02280499), a registered phase not stated study. The primary outcome is Radiological and Clinical Loosening Rates of the Glenoid and Humeral Components.

2. Clinical Question

3. Trial Design

This is a prospective, multicenter, postmarket clinical observation of the PROMOS Standard Shoulder System. The stated aim was to validate the system as a state-of-the-art implant for total shoulder arthroplasty in terms of radiographic and clinical performance and long-term survivorship over 10 years. That statement describes the study aim; it does not establish that the aim was met.

The registry lists 87 participants and identifies primary and secondary omarthrosis as the conditions of interest. The status is completed. The recorded start is 2003-11, and primary completion is 2015-03. These registry dates do not establish that every participant had the same duration of follow-up, or that every participant was observed for the full stated timeframe. Participant-level follow-up details are not reported in the registry record.

The listed intervention is the standard PROMOS prosthesis. No comparator is specified, and the study is not a randomized comparison; allocation is not stated. Its results should therefore be read as observations in the enrolled group, not as a controlled estimate of the difference between treatment strategies. Details such as the number of participating centers, eligibility criteria, recruitment procedures, protocol deviations, and loss to follow-up are not reported in the registry record.

The primary outcome is described as radiological and clinical loosening rates for the glenoid and humeral components, with percentage survivorship as the unit. The operational event in the endpoint description is revision due to aseptic loosening. The registry also lists Constant Murley Score and ASES Shoulder Score Index as secondary outcomes. Although 3 outcome measures are recorded, 0 analyses are listed. The record does not give outcome estimates, score summaries, or a statistical comparison.

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.

Before assignment: 93 patients were assessed for eligibility. Two participants were excluded before receiving the intervention due to not meeting the inclusion criteria. Four enrolled subjects did not receive a PROMOS™ prosthesis due to different reasons but were changed to another shoulder implant which was not part of the study.

Overall Study

Reasons for not completing this period:

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 Radiological and Clinical Loosening Rates of the Glenoid and Humeral Components, measured over up to 10 years.

The primary endpoint is labeled as radiological and clinical loosening rates of the glenoid and humeral components, reported as percentage survivorship over a timeframe of up to 10 years. Its description specifies that long-term survival was calculated with revision due to aseptic loosening as the endpoint, using Kaplan-Meier analysis. Thus, the stated event is revision for aseptic loosening; the description does not provide a separate numerical result for radiographic loosening findings or clinical signs of loosening.

Survival analysis is used when the outcome includes the time until an event, rather than only whether an event occurred. Kaplan-Meier estimation can account for participants whose event status is not observed throughout the full follow-up period, under appropriate assumptions about censoring. It produces an estimate of the probability of remaining event-free over time. In this study, that event-free measure is tied to revision due to aseptic loosening, not to every possible reason for revision or every radiographic change.

The registry gives the method and timeframe but does not report the estimated survivorship, number of endpoint events, confidence interval, or the timing of events. Consequently, the primary endpoint cannot be quantified from the registry record. The outcome population and detailed rules for event assessment are also not reported in the registry record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The primary outcome is framed as a time-to-event measure. The registry describes a Kaplan-Meier analysis of survivorship, with revision due to aseptic loosening serving as the endpoint. Understanding that method helps clarify what the stated outcome would represent, even though the registry record does not report the resulting estimate.

What does a time-to-event endpoint represent?

A time-to-event endpoint tracks both whether an event occurs and when it occurs. That differs from a simple count of participants with an event, because participants may have different lengths of observation. In this record, the specified event is revision due to aseptic loosening. A revision for another reason is not identified as the primary event in the description, and the registry does not explain how such cases were handled in the endpoint analysis.

Survivorship in this setting means remaining free of the defined event over time. It does not necessarily mean that a component had no radiographic findings or symptoms, because the operational event is revision for aseptic loosening. The primary outcome title mentions radiological and clinical loosening, while the analysis description defines the event through revision. These are related but not identical concepts; the record does not provide further endpoint adjudication details.

How does Kaplan-Meier estimation work?

In general, Kaplan-Meier estimation updates the estimated event-free probability at each observed event time. Participants who have not had the event contribute information while they are under observation. When their follow-up ends without an event being observed, they are typically censored at that point: their time under observation contributes, but they are not treated as having experienced the event. This allows the method to use information from participants whose observation ends before the full study timeframe.

That approach depends on knowing event times and censoring times, as well as appropriate assumptions about the censoring process. The registry specifies Kaplan-Meier analysis but does not report event times, censoring details, the number at risk over time, or the survival curve estimate. The method name alone does not reveal the amount of information available near the end of follow-up. It also does not resolve whether participants lost to observation differed in their risk of revision.

What does a confidence interval add?

A confidence interval expresses statistical uncertainty around an estimated quantity. A narrower interval indicates greater precision under the method's assumptions, while a wider interval indicates more uncertainty. The endpoint lists a 95% confidence interval as its dispersion measure, but no interval limits are reported in the registry record. It is therefore not possible to describe the precision of the primary survivorship estimate.

A confidence interval is not a guarantee that the true value lies within the particular interval, and its interpretation depends on the analysis assumptions and data. It cannot compensate for missing outcome reporting, uncertainty about follow-up, or lack of a comparator. Here, no interval is available to assess.

What do the planning illustrations mean?

Planning illustrations based on an observed effect are different from the trial's original sample-size justification. The stated illustration assumptions are a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation; the effect to detect is a stated fraction of the observed effect. For time-to-event tables, the stated quantity is the total number of events, while other tables use participants per arm. These are hypothetical planning calculations, not observed power and not evidence that this observational study was designed with those assumptions. The trial's own sample-size justification is not reported in the registry record.

The illustration framework refers to two-arm planning, whereas the registry describes no randomized comparison and specifies no comparator. Such a calculation cannot turn the cohort into a controlled comparison. Any planning result must be interpreted as a hypothetical design aid under its assumptions, not as a description of the actual enrollment process or observed study findings.

What can be inferred from the analysis listing?

The registry lists 3 outcome measures and 0 analyses. This means the record does not present analysis entries for the outcomes. The method stated in the primary endpoint description identifies an intended analytical approach, but it is not accompanied by results. Without estimates, uncertainty intervals, event counts, or analysis details, no recalculation or independent check of the primary analysis is possible.

10. Multiplicity, Missing Data and Analysis Populations

The registry identifies a primary endpoint and lists Constant Murley Score and ASES Shoulder Score Index as secondary outcomes. It records 3 outcome measures in total, but lists 0 analyses. No outcome estimates, hypothesis tests, or analysis-specific confidence intervals are reported. The record therefore does not show whether the primary and secondary outcomes were analyzed, or how any findings were interpreted together.

Multiplicity is a general statistical concern when several outcomes or hypotheses are tested: the chance of at least one apparently unusual result can increase as the number of tests increases. Analysts may address this through prespecified hierarchies, adjustment procedures, or a clearly defined distinction between confirmatory and exploratory outcomes. The registry record does not report whether any such plan or adjustment was used. It would be inappropriate to assume either that multiplicity was addressed or that it was ignored in the study conduct.

Missing-data methods, outcome-specific analysis populations, and exclusions from analyses are not reported in the registry record. The primary outcome population field is empty. The record does not state how participants with incomplete follow-up, missing score assessments, or unavailable event information were handled. It also does not report the number contributing data to each outcome. Enrollment alone should not be treated as the denominator for every analysis.

For Kaplan-Meier analysis, censoring is part of the method, but the registry does not describe censoring rules or the completeness of follow-up. No imputation method or sensitivity analysis is reported. These absences prevent assessment of how missing observations may affect the reported outcomes; in this record, the outcome estimates themselves are not reported either.

11. Safety Results

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

Other (non-serious) adverse events

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

Most frequent serious adverse event terms

Most frequent non-serious adverse event terms

Serious events with the highest arm-level rate: death (16.1%), revision of study device (5.7%), heart attack (2.3%), partial plexus paresis (1.1%), fall - traum. rupture of subscapularis (1.1%).

For the PROMOS Standard Shoulder System group, the registry reports 87 participants at risk for serious adverse events and 31 affected. For other adverse events, it reports 87 at risk and 2 affected. These are the recorded group figures; the registry does not provide event timing, participant-level detail, duration-adjusted rates, or a comparison with another group.

The listed top serious adverse-event terms and percentages are Death, 16.1%; Revision of study device, 5.7%; Heart attack, 2.3%; Partial Plexus paresis, 1.1%; Fall - traum. rupture of subscapularis, 1.1%; and Total shoulder arthroplasty contralateral side, 1.1%. The record lists these terms and values but does not explain the percentage denominator or how multiple events per participant were handled. The deaths field is null, so a death count is not reported in the registry record.

Adverse-event listings describe recorded events, not proof of causation. In particular, the presence of an event term in the device group does not establish that the device caused it. Without a specified comparator and further clinical context, these figures should not be interpreted as comparative risks or as a complete assessment of safety.

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

The registry establishes that a prospective, multicenter postmarket observation of the PROMOS Standard Shoulder System was conducted and is marked completed. It gives enrollment, the study aim, the primary endpoint definition, secondary outcome names, and selected adverse-event entries. Those details describe the study and the kinds of outcomes it was intended to evaluate.

The primary endpoint is intended to quantify survivorship up to 10 years, with revision due to aseptic loosening as the event in a Kaplan-Meier analysis. However, the registry record does not report the estimated survivorship, a confidence interval, endpoint event count, or time-specific numbers at risk. The endpoint's result and precision therefore cannot be judged from this record. The absence of a reported estimate is not evidence that the estimate was favorable, unfavorable, or zero.

The observational design does not provide a randomized control comparison. No comparator is specified, and allocation is not stated. As a result, the record cannot establish how outcomes would have differed under another implant or treatment strategy. The stated aim to validate the implant is not itself evidence that validation was achieved.

The secondary measures are named, but their scores and analyses are not reported. The safety entries provide counts of participants affected and a list of serious-event terms with percentages, but they lack comparative context and do not establish that events were caused by the device. The recorded number of deaths is not reported in the registry record.

In statistical terms, the record supports a description of the planned observational question and limited safety reporting, but not a conclusion about the magnitude or precision of clinical outcomes. Further outcome estimates and analysis details would be needed to assess survivorship, clinical scores, and comparative effects.

13. Why This Trial Matters Statistically

This study is statistically notable for the contrast between a long-term survival question and the limited results reported in the registry. The primary endpoint is explicitly framed as survivorship up to 10 years and names Kaplan-Meier analysis, a method suited to outcomes that occur over time when follow-up may end before an event. Yet the registry record does not give the survival estimate, its confidence interval, event counts, or risk-set information. A stated analytical method is not a substitute for its result.

The record also illustrates why outcome definitions need close reading. The primary title refers to radiological and clinical loosening rates, while the endpoint description defines the event as revision due to aseptic loosening. Revision is a specific clinical event and does not represent every radiographic finding or symptom. Without further endpoint details, the result, if available elsewhere, would need to be interpreted according to that operational definition.

The postmarket observational design provides a different kind of evidence from a randomized comparison. It can describe experience in the enrolled group, but the record specifies no comparator and no random allocation. This limits the claims that can be drawn about comparative effectiveness or causation. The aim of validating the system should not be confused with statistical confirmation that it performed better than an alternative.

Finally, the record lists secondary outcomes and adverse-event information but no analyses. This makes transparent outcome reporting especially important: estimates, uncertainty, follow-up completeness, and analysis populations are needed to understand what the observed data support. The registry entry is useful for defining the question and identifying reporting gaps, but it cannot by itself settle the primary statistical question.

14. 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 direct limitation is that the registry record does not report the primary survivorship estimate or its 95% confidence interval. It also does not report the number of revisions due to aseptic loosening or the timing of such events. As a result, the primary outcome cannot be quantified or assessed for precision from this record.

The description names a timeframe of up to 10 years but provides no distribution of follow-up, number at risk over time, or censoring details. It is not possible to tell from the record how many participants were observed for different portions of that timeframe. The start and primary completion dates do not fill this gap, because they do not describe participant-level follow-up.

The endpoint title refers to radiological and clinical loosening, but its description specifies revision due to aseptic loosening as the survival event. The record does not give separate radiographic results, clinical assessment criteria, event-adjudication procedures, or handling of revisions for other reasons. This limits the interpretation of what the primary endpoint captures.

The observational design has no specified comparator and is not randomized; allocation is not stated. Any outcomes recorded for the PROMOS group cannot by themselves distinguish implant-related effects from other influences. The registry also does not report eligibility details, center-level information, loss to follow-up, analysis populations, missing-data methods, or sensitivity analyses.

Finally, 3 outcome measures are recorded but 0 analyses are listed. The secondary score results are not reported, and safety entries do not include a comparator or causal attribution. These are limitations of the registry reporting; they should not be read as proof that analyses or additional data do not exist outside the registry record.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Multicenter Clinical Observation PROMOS® — NCT02280499.
• Registry record last updated 2016-03-21; status last verified 2016-02.
• Results first posted 2016-03-21.
• 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.

18. Record Summary

The registry record describes a completed, prospective, multicenter postmarket clinical observation of the PROMOS Standard Shoulder System in people with primary and secondary omarthrosis. Enrollment was 87. The recorded start was 2003-11, and primary completion was 2015-03.

The primary outcome concerns radiological and clinical loosening of the glenoid and humeral components, expressed as percentage survivorship up to 10 years. Its description specifies Kaplan-Meier analysis with revision due to aseptic loosening as the event. Constant Murley Score and ASES Shoulder Score Index are listed as secondary outcomes.

No comparator is specified, the study is not a randomized comparison, and allocation is not stated. The registry records 3 outcome measures and 0 analyses. The primary survivorship estimate, confidence interval, secondary outcome results, analysis populations, and missing-data methods are not reported in the registry record. Safety entries report 31 affected among 87 at risk for serious adverse events and 2 affected among 87 at risk for other adverse events.