This page provides an independent statistical analysis and educational interpretation of publicly reported results. ClinicalTrials.gov provides the official trial registry record. Numerical trial results on this page are restricted to the results posted in the ClinicalTrials.gov record; calculations added by Clinical Biostats are labelled as such.
1. Trial at a Glance
This page covers the registry results for The PreOperative Management of Patients Awaiting Anterior Cruciate Ligament Reconstruction (NCT05529511), a registered phase not stated study. The primary outcome is Number of Participants Who Completed Semi-structured Interviews.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT05529511 |
| Phase | Phase not stated |
| Condition | Anterior Cruciate Ligament Injuries, Anterior Cruciate Ligament Rupture, Rehabilitation |
| Allocation | Not Stated |
| Design model | Not Stated |
| Masking | Not Stated |
| Enrollment | 26 |
| Arms in the primary outcome | n/a |
| Lead sponsor | University Hospitals of Derby and Burton NHS Foundation Trust |
| Results posted | Yes |
2. Clinical Question
Population
People experiencing an anterior cruciate ligament rupture and proceeding with agreed surgical management, with interviews planned at different points around surgery. The registry record describes participants interviewed before surgery, 3 months after surgery, and 12 months after surgery. It also describes a consensus panel involving clinicians, patients, and stakeholders.
Intervention
There is no clinical treatment intervention being tested against a control in the described study. Phase 1 consists of semi-structured interviews about the treatment pathway. Phase 2 is a Nominal Group Technique consensus meeting intended to develop a prehabilitation intervention.
Comparator
No like-for-like control group or randomized allocation is reported. The interview time points are stages in the pathway, not treatment arms for a randomized comparison. The registry record does not state how participants were allocated to the listed phases.
Primary question
The primary endpoint counts participants who completed semi-structured interviews. The interviews are intended to explore lived experiences after ACL rupture and agreed surgical management. The central question is descriptive and exploratory: what experiences do patients report along the treatment pathway, and how can patient, clinician, and stakeholder input contribute to developing prehabilitation?
The study is registered as The PreOperative Management of Patients Awaiting Anterior Cruciate Ligament Reconstruction: a Mixed-methods Study. Its stated motivation is that patient experiences of the NHS ACL treatment pathway are unknown. The three interview time points are designed to capture experiences at different stages rather than estimate a treatment effect. The consensus meeting has a separate development purpose. The registry record does not report a quantitative comparison of prehabilitation with another approach, nor does it report patient-experience findings. Accordingly, the central statistical reading is about the scope and completeness of the recorded evidence, not whether a treatment changes an outcome.
3. Trial Design
This is a completed study sponsored by University Hospitals of Derby and Burton NHS Foundation Trust. The registry record lists a start date of 2022-08-03, a primary completion date of 2023-08-30, and enrollment of 26. The study title identifies a mixed-methods design, and the described activities are semi-structured interviews and a consensus meeting rather than a randomized treatment comparison.
Phase 1 is described as preoperative interviews, with approximately 12 participants at three pathway time points: before ACL surgery, 3 months after surgery, and 12 months after surgery. The brief summary describes 12 participants at each time point, including up to 2 weeks before surgery. Phase 2 is a Nominal Group Technique panel with up to 12 participants, comprising clinicians, patients, and stakeholders, to develop a prehabilitation intervention. These are descriptions of intended activities; the registry record does not give completed counts for each interview time point or for the panel.
The total enrollment is 26, while the brief description outlines 12 participants at each of three interview time points and a panel of up to 12. These figures describe different aspects of the study record and should not be combined into an assumed participant flow. The record does not say whether the same people contributed at more than one time point, how the panel participants related to interview participants, or how many people completed each activity.
Allocation is not stated, and the listed phases are not comparable control arms. The record lists two outcome measures and zero analyses. It does not report a randomized design, a statistical analysis plan, or quantitative treatment-effect results. The appropriate design description is therefore an exploratory pathway-experience study with an additional consensus-development phase, not a trial comparing clinical effectiveness between treatment groups.
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
| Stage | Phase 1 - Preoperative | Phase 2 - Nominal Group Technique Panel |
|---|---|---|
| STARTED | 18 | 8 |
| COMPLETED | 18 | 8 |
| NOT COMPLETED | 0 | 0 |
Analysis population for the primary outcome, as defined in the registry: All participants remained in the study.
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.
| Characteristic | Unit | Phase 1 - Preoperative | Phase 2 - Nominal Group Technique Panel | Total |
|---|---|---|---|---|
| Participants analysed | 18 | 8 | 26 | |
| Age, Continuous | years | 29 (18 to 45) | NA (NA to NA) | NA (NA to NA) |
| Sex: Female, Male: Female | Participants | 3 | NA | NA |
| Sex: Female, Male: Male | Participants | 15 | NA | NA |
| Race/Ethnicity, Customized: White | Participants | 14 | NA | NA |
| Race/Ethnicity, Customized: Indian | Participants | 2 | NA | NA |
| Race/Ethnicity, Customized: British Asian | Participants | 1 | NA | NA |
| Race/Ethnicity, Customized: Pakistani | Participants | 1 | NA | NA |
| Time-point on the pathway: Preoperative | Participants | 10 | NA | NA |
| Time-point on the pathway: 3-months post-operative | Participants | 6 | NA | NA |
| Time-point on the pathway: 12-months postoperative | Participants | 2 | NA | NA |
6. Primary Endpoint
The registry lists the primary outcome as Number of Participants Who Completed Semi-structured Interviews, measured over Interviews completed within approximately 60 minutes.
| Element | Registry entry |
|---|---|
| Result type | Count Of Participants |
| Measure of spread | not applicable |
| Unit | Participants |
| Endpoint classification | Binary Endpoint |
The primary endpoint is the number of participants who completed semi-structured interviews. Its unit is participants, and the registry describes the interview duration as approximately 60 minutes. The interview content is intended to help understand patients’ lived experiences of the treatment pathway following an ACL rupture and agreed surgical management. The record states that qualitative data are collected through individual semi-structured interviews.
A completion count is useful as a process measure: it indicates how many participants contributed interview data. In a multi-time-point study, such counts can help readers assess whether planned data collection took place at the different stages. However, the endpoint as stated does not quantify the content, diversity, or meaning of participants’ accounts. It also does not measure a clinical outcome or compare the effects of different treatments.
The registry record identifies the endpoint but does not report the number who completed interviews, a breakdown by time point, or a qualitative summary of what participants said. It describes the endpoint population as all participants remaining in the study, but does not provide a participant-flow account to clarify completion at each stage. As a result, the endpoint’s purpose can be described, but its observed value and completeness across the pathway cannot be assessed from the registry record.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry record identifies a completed mixed-methods study focused on experiences of the NHS ACL treatment pathway. Its primary endpoint is a participant count for semi-structured interview completion. The record does not report the observed count for that endpoint, interview findings, or a statistical analysis. Enrollment is reported as 26, but enrollment alone does not establish how many participants completed interviews or contributed at each time point.
The planned interview stages are before surgery, 3 months after surgery, and 12 months after surgery. The brief summary describes 12 participants at each stage, while the arm description says approximately 12 participants at three time points. These are descriptions of the intended interview sampling, not reported completion results. The registry record does not specify whether repeated interviews involved the same participants, or give the number interviewed at each stage. It is therefore not possible to judge retention across the stages or the extent to which the planned coverage was achieved.
The second phase is a consensus meeting with up to 12 clinicians, patients, and stakeholders, intended to develop a prehabilitation intervention. This phase is not a control arm for assessing the interview phase, and the record does not report the consensus outcome or the resulting intervention details. No randomized allocation or treatment comparison is reported. The two phases answer different kinds of questions: interviews are intended to elicit experiences, while the panel is intended to support intervention development.
There are no reported effect estimates, confidence intervals, hypothesis tests, or analysis results in the registry record. That absence is consistent with the record’s zero listed analyses, but it does not reveal whether analyses were conducted outside the registry record. It means readers cannot use this record to quantify uncertainty around a treatment effect or determine the prevalence of particular experiences.
The adverse-event figures report zero serious adverse events, zero other adverse events, and zero deaths in the Phase 1 group, with 18 participants at risk. The Phase 2 panel has zero participants at risk recorded. These figures are descriptive registry entries and do not establish comparative safety. The lack of participants at risk recorded for Phase 2 means its zero event counts cannot be read as evidence that no events occurred among an observed panel population.
The main conclusion supported by the registry record is about study intent and reporting: it was designed to explore pathway experiences at specified points and to convene a development-focused consensus panel, but the record does not provide the primary completion result or substantive findings. The status COMPLETED does not fill in those missing results. Any interpretation of the interview content, intervention developed, or clinical benefit would go beyond what the record reports.
9. Statistical Methods Explained
The registry describes semi-structured interviews and a consensus meeting. It does not report a statistical analysis plan, a named qualitative analysis method, a coding framework, or quantitative comparisons. The methods below distinguish what the record says from general statistical context, so that descriptive counts are not mistaken for evidence of a treatment effect.
What does a completion count tell readers?
The primary outcome is a count of participants who completed interviews. A count describes the amount of participation recorded for that endpoint. It is not, by itself, a measure of how representative the interview accounts are, how rich the interviews were, or what themes emerged. To interpret a completion count in a study with multiple interview time points, readers would generally want counts for each time point and an account of whether participants returned for later interviews. Those details are not reported in the registry record.
General statistical context: a count is often summarized directly rather than treated as a continuous measurement with a mean and standard deviation. If counts are modeled, the appropriate model depends on how they arise and on the design. No count model or other statistical model is reported for this study. The endpoint’s stated unit and purpose should therefore guide interpretation rather than assumptions about an unreported model.
Why is this not a conventional arm comparison?
The record describes two phases with different purposes: interviews to understand experience and a consensus panel to develop prehabilitation. Allocation is not stated, and the listed groups are not like-for-like controls. A difference between their counts, even if such counts were reported, would not automatically estimate a treatment effect because the phases represent different activities and populations.
General statistical context: treatment-effect estimates in comparative studies depend on a clearly defined contrast between groups, an appropriate design, and an analysis that reflects allocation and outcome measurement. Randomization can support comparability of groups at baseline, but no randomized comparison is reported. It would not be appropriate to interpret the phases as randomized arms or to calculate a comparative effect from their adverse-event entries.
What would an estimate and confidence interval mean?
General statistical context: an estimate is a numerical summary of an effect or quantity in the observed data. A confidence interval describes uncertainty around an estimate under the assumptions of the method used. Narrower intervals generally indicate greater precision, while wider intervals indicate less precision. An interval does not remove design limitations or show that an association is causal.
No effect estimate or confidence interval is reported for the interview-completion endpoint, and no quantitative effect comparison is described. The registry record therefore does not support a precision assessment for a treatment effect. For the qualitative objective, the relevant evidence would include the interview findings and how they were analyzed; those findings and methods are not reported in the registry record.
How should sample-size illustrations be treated?
General statistical context: a sample-size calculation is a planning tool. Its result depends on assumptions about the outcome, the effect to detect, the significance level, allocation, and the statistical method. The record describes planning illustrations based on a fraction of an observed effect, with a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. It also distinguishes participant-per-arm calculations from total-event calculations for time-to-event outcomes.
Those assumptions describe illustrations, not the design of this study. The registry does not report a randomized two-arm comparison or a quantitative observed treatment effect on which to base a conventional power interpretation. Planning illustrations must not be read as observed power or as evidence that the study could detect a particular clinical effect. No sample-size justification for the study itself is reported in the registry record.
What does over-dispersion mean in general?
General statistical context: over-dispersion occurs when observed variation in count data exceeds what a chosen model expects. If ignored, standard errors and uncertainty intervals from that model may be too small, making results appear more precise than they are. Whether over-dispersion matters depends on the outcome and model. The registry record does not report a count model or a dispersion assessment, so no conclusion about over-dispersion can be drawn for this study.
Overall, the methods information supports a descriptive reading of the study activities and endpoint definition. It does not supply enough detail to reconstruct qualitative analysis, infer a quantitative comparison, or assess model-based uncertainty.
10. Multiplicity, Missing Data and Analysis Populations
The registry record lists two outcome measures and zero analyses. It does not identify a primary statistical hypothesis, a family of comparisons, an adjustment for multiple testing, or an interim analysis plan. As no inferential results are reported, there are no reported p-values or confidence intervals whose multiplicity handling can be evaluated. The absence of a reported adjustment should not be interpreted as evidence that one was or was not used outside the registry record.
Missing-data handling is also not described. In a study with interviews planned at three pathway time points, relevant reporting would include the number of participants completing each time point, any incomplete interviews, and the reasons for missing contributions where known. The registry record does not provide those details. It states that the primary endpoint population is all participants who remained in the study, but does not provide a participant-flow account or explain how that population relates to the endpoint result.
The record does not report an analysis population definition beyond that endpoint description, nor does it describe how qualitative material from incomplete or repeated interviews would be handled. It is not possible to determine whether missing interviews were excluded, whether any sensitivity analysis was conducted, or whether the panel’s participation was complete. Those matters are not reported in the registry record.
For a qualitative study, completeness is not only a matter of a numerical denominator. The content and context of participants’ accounts and the analytic approach are important to interpreting findings. The registry record does not report interview themes or an analysis method, so readers cannot assess how missing contributions might have affected the reported interpretation.
11. Safety Results
The registry reports serious adverse events as affected participants divided by participants at risk.
| Arm | Participants with serious adverse events | Participants at risk | Percentage |
|---|---|---|---|
| Phase 1 - Preoperative | 0 | 18 | 0.0% |
Deaths
| Arm | Deaths (participants affected of at risk) |
|---|---|
| Phase 1 - Preoperative | 0 of 18 |
| Phase 2 - Nominal Group Technique Panel | 0 of 0 |
Other (non-serious) adverse events
Participants with at least one non-serious event at or above the registry's 0% reporting threshold.
| Arm | Participants affected of at risk |
|---|---|
| Phase 1 - Preoperative | 0 of 18 |
| Phase 2 - Nominal Group Technique Panel | 0 of 0 |
The adverse-event record lists the Phase 1 preoperative group with 18 participants at risk: serious adverse events are recorded as 0, other adverse events as 0, and deaths as 0. No serious adverse-event terms are listed. For the Phase 2 Nominal Group Technique panel, the record gives 0 participants at risk and records 0 serious adverse events, 0 other adverse events, and 0 deaths.
These are descriptive entries, not a comparison between randomized treatment groups. In particular, the Phase 2 entry has no participants at risk recorded; its zero counts should not be interpreted as an observed event-free experience among a panel population. The Phase 1 counts describe the registry entries for that group, but the record does not report follow-up duration for safety, event definitions, or a comparative safety analysis.
A zero count does not establish that the underlying risk is zero. General statistical context: when few or no events are observed, the data may still be compatible with a range of possible event rates, and precision depends on the population observed and the duration and completeness of follow-up. No such interval or risk estimate is reported. The safety entries should therefore be read narrowly as recorded counts, not as proof of safety or as a treatment-effect result.
12. What the Result Does, and Does Not, Mean
The registry record establishes the study’s purpose and broad structure. It sought to explore patient experiences of the NHS ACL treatment pathway at multiple points around surgery and to use a consensus meeting to develop a prehabilitation intervention. It reports enrollment of 26 and identifies interview completion as the primary endpoint. The record is marked COMPLETED.
What it does not establish is the number of completed interviews, the number completing interviews at each planned time point, the themes or conclusions from those interviews, or the result of the consensus process. It also does not report a statistical treatment comparison, an effect estimate, or a confidence interval. Completion status and enrollment do not substitute for those results.
The study is not described as a randomized comparison. Its phases serve different purposes, and allocation is not stated. Consequently, the registry record cannot show whether one treatment is better than another, or whether the planned prehabilitation intervention changes a clinical outcome. The consensus meeting’s aim to develop an intervention is not itself evidence that the intervention is effective.
The adverse-event counts are limited descriptive information. The Phase 1 record lists 18 participants at risk and zero serious and other adverse events and deaths. The Phase 2 record lists zero participants at risk, so its zero counts do not provide an observed panel safety estimate. Neither entry supports a comparative safety conclusion.
General statistical context: a study can contribute useful information without producing a treatment-effect estimate. Exploratory interviews can inform understanding of experiences, while consensus methods can help shape an intervention. To judge those contributions, readers need the findings and transparent descriptions of analysis and participation. Those details are not reported in the registry record. The most defensible interpretation is therefore limited to the stated aims, activities, enrollment, and recorded event counts, with no claim about clinical benefit or lack of benefit.
13. Why This Trial Matters Statistically
This study raises a statistical interpretation issue that is common when a registry labels a project as a clinical trial or lists outcome measures: not every clinical study is designed to estimate a comparative treatment effect. The described work centers on patient experience and intervention development. Its main endpoint counts interview completion, while the substantive aims concern qualitative accounts and a consensus process.
Separating process measures from clinical outcomes matters. A count of completed interviews can describe participation, but it does not summarize what people experienced or establish whether a treatment changed an outcome. Likewise, a completed registry status does not mean that an interpretable outcome result is available in the record. Clear reporting needs to connect the planned activities to completed participant counts and findings.
The study also illustrates why groups should not be treated as trial arms merely because they appear as separate groups in a registry. The interview phase and the panel phase have different roles, and no randomized allocation or like-for-like comparison is reported. Comparing their entries as if they were treatment groups would give the numbers a meaning the design does not support.
Finally, transparent reporting of participant flow is especially useful when data collection is planned at multiple stages. Counts by time point and information about repeat participation would help readers understand the scope of the collected experience data. The registry record does not report those details. These distinctions help prevent descriptive counts, planned activities, and missing results from being mistaken for evidence about treatment efficacy.
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 registry record does not report the observed primary endpoint value, despite identifying the number of participants who completed semi-structured interviews as the primary outcome. It also gives no completed interview counts by time point, no interview findings, and no results from the consensus meeting. This prevents assessment of whether the intended data collection was achieved and what the study learned.
The participant-flow details are limited. Enrollment is 26, while the study descriptions refer to 12 participants at each of three interview time points and a consensus panel of up to 12. The record does not explain overlap among these groups, repeat participation, or completion by activity. It is therefore not possible to infer a total number of unique contributors from the planned figures.
The registry record does not report the qualitative analytic approach, how interview material was coded or interpreted, how consensus was reached, or how disagreements were handled. These details would help readers assess the basis and scope of qualitative conclusions, but no conclusions are reported to evaluate.
Allocation is not stated, and the phases are not like-for-like control groups. There is no reported statistical analysis plan or treatment-effect estimate. The safety record also has limited interpretability: Phase 2 has no participants at risk recorded, and the record does not describe safety follow-up duration or event definitions. Finally, no study-specific sample-size justification or missing-data procedure is reported in the registry record. These limitations concern what can be assessed from the registry record; they do not establish what may or may not have been done outside it.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: The PreOperative Management of Patients Awaiting Anterior Cruciate Ligament Reconstruction — NCT05529511.
- Registry record last updated 2025-04-15; status last verified 2025-04.
- Results first posted 2025-04-15.
- 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.
Continue through the Clinical Biostats statistical pathway
Use this trial's endpoint as a starting point for deeper study of effect measures, confidence intervals, and sample-size planning.
18. Record Summary
NCT05529511 is a completed mixed-methods study titled The PreOperative Management of Patients Awaiting Anterior Cruciate Ligament Reconstruction. It is sponsored by University Hospitals of Derby and Burton NHS Foundation Trust. The record lists enrollment of 26, a start date of 2022-08-03, and a primary completion date of 2023-08-30.
The study describes semi-structured interviews before surgery, 3 months after surgery, and 12 months after surgery, plus a Nominal Group Technique panel intended to develop a prehabilitation intervention. The primary endpoint counts participants who completed interviews. The record lists two outcome measures and zero analyses, but does not report the primary endpoint result or substantive study findings.
Allocation is not stated, and the phases are not a randomized control comparison. Safety entries list zero recorded events in Phase 1 among 18 participants at risk; Phase 2 has zero participants at risk recorded. The registry record does not report a statistical analysis plan, qualitative analysis method, or missing-data approach.