Ambispective Study to Assess the Safety and the Performance of SAGITTA EVL R Stem: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Ambispective Study to Assess the Safety and the Performance of SAGITTA EVL R Stem (NCT06096155), a registered phase not stated study. The primary outcome is Survival Rate at Mid/Long Term Follow-up.

2. Clinical Question

3. Trial Design

The registry identifies this as an ambispective study of SAGITTA EVL R revision femoral stems used in hip arthroplasty. The title and study description establish that the focus is clinical data on the device, but the registry record does not explain which information was collected retrospectively and which was collected prospectively. The study is listed as completed, with enrollment of 46. Its recorded start date is 2023-06-13 and its primary completion date is 2024-06-06.

The primary objective is to evaluate long-term stem survival at 7 to 10 years post-operation, with a stated allowance of +/- 2 years. Secondary objectives concern patient satisfaction, possible complications, and clinical-score performance. The listed secondary outcomes include Patient's Satisfaction, Adverse Events, Oblivion of Prosthesis, Absence of Squeaking, and Functional Improvement. The meaning or operational definition of “Oblivion of Prosthesis” is not reported in the registry record.

No randomized allocation is described; allocation is not stated. The record explicitly cautions that the arms used in planning illustrations are not a like-for-like control comparison. It therefore does not establish a controlled trial contrast. The listed Per Protocol Population relates to the adverse-event figures, but criteria for that population and its relationship to enrollment are not reported in the registry record. The primary outcome population is also not specified. Completion status indicates the recorded study status, not that the long-term outcome has been analyzed or reported.

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:

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 Survival Rate at Mid/Long Term Follow-up, measured over At 7/10 years after surgery.

The primary endpoint is implant survival expressed as a percentage at mid- or long-term follow-up. The registry specifies assessment at 7/10 years after surgery and defines the event in relation to revision, whatever the cause of revision. Thus, the endpoint is intended to describe whether stems remain unrevised at the stated follow-up horizon, rather than to measure a clinical score or patient satisfaction directly.

Survival endpoints are useful for implanted devices because revision is a clinically relevant event that can be tracked over time. They can describe durability across follow-up even when participants are not all observed for an identical period. Interpreting such an estimate generally depends on how follow-up time, censoring, and events are defined and handled. Those analysis details are not reported in the registry record.

The registry gives the endpoint definition and timeframe but does not provide an observed survival percentage, event count for revision, confidence interval, or other measure of precision. The posted record therefore identifies the intended question but does not establish the measured long-term survival result. It also does not report whether all participants reached the intended follow-up window.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The registry record names the primary outcome and reports some adverse-event counts, but it does not describe a complete statistical analysis plan. The following concepts explain how such outcomes are commonly interpreted in general; they should not be taken as a description of methods used in this study unless the record states them.

What does implant survival measure?

In general, a survival analysis follows participants over time until a defined event occurs or observation ends. For an implant-survival endpoint, the event definition is especially important. In this study, the registry describes the outcome as survival at 7/10 years after surgery and says that revision is considered whatever its cause. An estimate at a follow-up horizon is often presented as a percentage, matching the stated unit of this endpoint.

Some participants may not have complete follow-up to the target time. Statistical methods can account for differing observation times, but interpretation then depends on assumptions about censoring and on accurate recording of event dates. The registry record does not describe censoring rules, revision-date handling, or whether a time-to-event estimator was used. It also does not report a survival estimate or its confidence interval. A confidence interval, in general, expresses the statistical uncertainty around an estimated quantity; its absence leaves the precision of the primary result unreported.

Why does the event definition matter?

A survival percentage is only interpretable in light of the event and the population being followed. Here the event is revision, regardless of cause. This definition does not itself explain how deaths or loss to follow-up were handled in the survival analysis. In general, death can prevent a later revision from being observed, and analysts may handle that situation in different ways depending on the question. No such method is stated in the registry record. The record lists 23 deaths in its adverse-event information, but does not link those deaths to the primary survival analysis.

What can adverse-event counts tell readers?

Counts of participants affected describe how many people in a stated population had recorded events, subject to the event definitions and observation period. The record states that 15 of the 46 at-risk participants in the Per Protocol Population were affected by serious adverse events, and that 8 of the 46 at-risk participants were affected by other adverse events. These are separate registry figures; the record does not explain whether participants could be represented in both categories, how repeated events were counted, or the follow-up period for the counts.

General interpretation also depends on distinguishing the number of people with an event from the number of events. A participant may experience more than one event, so these quantities need not be interchangeable. The listed serious-event terms have percentages attached, but the registry record does not state the denominator or whether the percentages refer to participants or events. They should not be treated as directly comparable rates without that information.

What do the planning assumptions mean?

The record describes planning illustrations using a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. It states that the effect to detect is a stated fraction of the observed effect. It also notes that time-to-event calculations use the total number of events under the Schoenfeld approach, while other calculations express participants per arm. These are planning assumptions, not evidence that the study itself used a randomized two-arm design. The record separately says that allocation is not stated and warns that the arms are not a like-for-like control comparison.

Sample-size calculations estimate the amount of information that might be needed under specified assumptions. Their results depend on the assumed effect and other design choices. A planning illustration based on an observed effect is not observed power, and it does not replace an analysis of trial outcomes. No numerical planning outputs are reported in the registry record, so the assumptions alone do not reveal a target sample size or establish that the study could estimate long-term survival precisely.

What does the record say about statistical testing?

The registry reports zero analyses and does not state a model, hypothesis test, confidence interval method, adjustment strategy, or analysis population for the primary outcome. It is therefore not possible to determine from the record whether any formal statistical test was conducted, whether the primary result was adjusted for participant characteristics, or how missing endpoint information was handled. Statistical methods can clarify uncertainty and account for features such as unequal follow-up or over-dispersion in count data, but the appropriate approach depends on the data structure and prespecified question. Those details are not reported in the registry record.

10. Multiplicity, Missing Data and Analysis Populations

The registry lists six outcome measures and names secondary outcomes concerning satisfaction, adverse events, prosthesis-related experience, squeaking, and functional improvement. It identifies long-term survival as the primary objective. However, the record does not report a hierarchy among the outcomes beyond that primary designation, nor does it describe which outcomes were formally tested or how results were selected for reporting.

When multiple outcomes are examined, the chance of at least one apparently notable result can increase if each is tested separately. In general, a prespecified outcome hierarchy or multiplicity adjustment can help readers interpret a family of statistical tests. The registry record does not report such a strategy, and it lists zero analyses. Since no outcome estimates or tests are posted, there is no basis for judging whether multiplicity affected any result.

Missing-data methods are also not reported in the registry record. The primary endpoint targets follow-up at 7/10 years after surgery, but the record does not state how participants without that follow-up were handled, whether data were censored, or how missing outcome information was assessed. It does not report follow-up completeness for the survival endpoint.

The record identifies a Per Protocol Population for adverse-event figures but does not define its membership or explain whether it was also used for other outcomes. The primary outcome population is not stated. As a result, readers cannot determine from the registry record whether the safety and performance outcomes refer to the same analysis population or how exclusions from analysis may have affected interpretation.

11. 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 serious adverse event terms

Most frequent non-serious adverse event terms

Serious events with the highest arm-level rate: revision (4.3%), deep vein thrombosis (4.3%), replacement of locking screw (4.3%), femoral fracture due to a fall (2.2%), pain (2.2%).

The adverse-event record gives figures for the Per Protocol Population. It reports 15 participants affected by serious adverse events among 46 at risk, and 8 participants affected by other adverse events among 46 at risk. It also records 23 deaths. The registry record does not report the timing or causes of deaths, whether they were considered related to the implant or procedure, or how they were handled in analysis of implant survival.

The listed serious-event terms and percentages are Revision, 4.3%; Deep vein thrombosis, 4.3%; Replacement of locking screw, 4.3%; femoral fracture due to a fall, 2.2%; Pain, 2.2%; and Infection, 2.2%. The record does not specify whether these percentages use participants or events as the denominator, nor does it state whether repeated events in a participant are counted separately. They should therefore be read as reported term-specific figures, not as a fully defined incidence estimate.

These observations describe recorded events but do not establish causation. The record does not provide a comparison group, attribution rules, or event-specific follow-up time. Safety interpretation is consequently limited to the stated counts and terms, with important context not reported in the registry record.

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

The registry record establishes that the study was intended to assess long-term survival, safety, and performance of SAGITTA EVL R revision femoral stems in hip arthroplasty. It reports enrollment of 46, a completed status, and some adverse-event counts. These details help identify the study and the type of evidence it sought to collect.

What the record does not establish is the primary long-term survival result. Although the endpoint is specified as survival at 7/10 years after surgery, no percentage, confidence interval, or revision analysis is reported. The record also does not provide results for the listed secondary outcomes. Without outcome estimates and their precision, readers cannot assess how closely the observed data support the stated performance objectives.

The adverse-event figures are descriptive and lack reported detail about timing, attribution, definitions, and the denominator for term-specific percentages. They should not be interpreted as proof that an event was caused by the stem or as a comparison of risk against another device. Allocation is not stated, and the record cautions that arms used in planning illustrations are not like-for-like controls. Accordingly, the posted information does not support a causal treatment comparison.

In general, a study result is most informative when the endpoint definition, analysis population, follow-up, estimate, and uncertainty are reported together. Those elements are incomplete or absent for the primary outcome in this registry record. The appropriate reading is therefore limited: the study objective and some safety observations are recorded, while the central long-term performance result and its statistical precision are not reported in the registry record.

13. Why This Trial Matters Statistically

Long-term implant survival is a consequential statistical question because a device may be followed over an extended period and participants may have different durations of observation. The endpoint definition matters: this study specifies survival at 7/10 years after surgery and treats revision, whatever the cause, as the event. Clear reporting of the estimate, its uncertainty, event handling, and follow-up would allow readers to assess what the observed data say about durability.

This study is also a useful example of the distinction between a stated objective and a reported result. The registry identifies a long-term primary objective, but the posted record does not provide the survival percentage or an analysis. A completed status alone does not convey the direction or precision of an endpoint result. Statistical interpretation needs outcome data, not only an endpoint description.

The adverse-event information illustrates another important issue: counts and percentages require context. Readers need to know the event definitions, denominators, time at risk, and whether counts refer to people or repeated events. The registry lists several serious-event terms and reports counts of affected participants, but does not provide all of those interpretive details. This limits comparisons and causal conclusions.

Finally, the planning assumptions should be separated from the study's observed evidence. The record describes illustrative sample-size calculations, but does not report their numerical outputs or a formal analysis plan. Such assumptions cannot stand in for observed results or establish power after the fact. Together, these features make transparent reporting of endpoint estimates, precision, populations, and missing-data handling especially important for understanding the study.

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 primary limitation of the posted record is that it does not report the outcome central to the study objective: the survival percentage at 7/10 years after surgery. No precision estimate, revision-event count for that endpoint, or analysis method is stated. The record therefore cannot show how the observed data relate to the intended long-term performance question.

The study is described as ambispective, but the registry record does not explain the retrospective and prospective components or the procedures used to assemble and follow the data. Eligibility criteria, baseline participant characteristics, surgical details, and device-use consistency are not reported. The primary outcome population is unspecified, and the Per Protocol Population used for adverse-event figures is not defined.

Follow-up completeness and missing-data handling are not reported. This is material for a long-term survival endpoint because interpretation depends on the observation period and how participants without complete follow-up are treated. The record also does not specify censoring rules or how deaths relate to the primary endpoint analysis.

For safety, the record lists counts and event terms but omits timing, attribution, detailed definitions, and the denominator basis for term-specific percentages. It does not report a comparison group suitable for causal inference; allocation is not stated, and the record warns that planning arms are not like-for-like controls. The record lists zero analyses and provides no statistical analysis plan, multiplicity approach, or outcome estimates for the secondary measures. These omissions limit both precision and interpretability.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Ambispective Study to Assess the Safety and the Performance of SAGITTA EVL R Stem — NCT06096155.
• Registry record last updated 2026-06-30; status last verified 2025-04.
• Results first posted 2026-06-30.
• 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

NCT06096155 is a completed ambispective study sponsored by Societe dEtude, de Recherche et de Fabrication. It concerns hip arthroplasty with SAGITTA EVL R revision femoral stems, lists enrollment of 46, and records a start date of 2023-06-13 and primary completion date of 2024-06-06.

The primary objective is long-term stem survival at 7/10 years after surgery, with revision as the event regardless of cause. Secondary objectives address satisfaction, complications, and clinical-score performance. The registry record does not report the primary survival result or statistical analyses.

For the Per Protocol Population, the record reports 15 participants affected by serious adverse events among 46 at risk, 8 affected by other adverse events among 46 at risk, and 23 deaths. Event timing, attribution, and several analysis details are not reported in the registry record. The record also cautions that the planning arms are not like-for-like controls.