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 Post-Op Rotator Cuff Pain Study With Subacromial Bupivacaine Infusion (NCT01126593), a randomized na study. The primary outcome is Pain Scores.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT01126593 |
| Phase | NA |
| Condition | Rotator Cuff Tear |
| Allocation | Randomized |
| Design model | Parallel |
| Masking | Double |
| Enrollment | 96 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Orlando Health, Inc. |
| Results posted | Yes |
2. Clinical Question
Population
People undergoing arthroscopic rotator cuff repair for a rotator cuff tear. The registry record lists an enrollment of 96, but does not report additional eligibility details or the characteristics of participants who entered each analysis.
Intervention
A subacromial continuous infusion catheter with 200cc of 0.5% bupivacaine in its reservoir, infused at 4cc per hour.
Comparator
Two comparison conditions are listed: a catheter with 200cc of 0.9% normal saline in its reservoir, and no continuous infusion catheter.
Primary question
How did pain scores measured after surgery compare across the bupivacaine, saline-catheter, and no-catheter groups? The registry record states a null hypothesis that continuous subacromial bupivacaine infusion would provide no pain-control benefit over placebo infusion or no catheter use. It does not report the outcome analyses needed to answer that question.
3. Trial Design
The registry identifies this as a randomized, double-masked, parallel trial. It lists 96 participants as enrolled and describes three groups: a bupivacaine infusion group, a placebo group receiving saline through a catheter, and a control group receiving no continuous infusion catheter. The trial status is completed. The listed start and primary-completion dates are 2008-12 and 2009-11.
The active group is described as receiving a subacromial continuous standard spring-loaded infusion catheter containing 200cc of 0.5% bupivacaine, with an infusion rate of 4cc per hour. The placebo group receives the same type of catheter, with 200cc of 0.9% normal saline in the reservoir. The control group receives no continuous infusion catheter. This design therefore includes both a saline-catheter comparison and a no-catheter comparison, as well as the bupivacaine group.
Randomization is the allocation method listed in the registry. The record describes masking as double, but does not state which people were masked or how masking was maintained, particularly for the comparison involving no catheter. The allocation ratio, sequence-generation procedure, concealment method, and any details about adherence or treatment deviations are not reported in the registry record. The phase is listed as NA.
The registry record does not identify an analyzed participant count for the pain outcome or present a statistical comparison among the groups. Enrollment describes the overall trial entry count; it should not be taken as evidence that every enrolled participant contributed data at every measurement time.
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: If patient met the inclusion criteria and agreed to participate, they were given the consent to sign and were randomized into the trial.
Overall Study
| Stage | Placebo Group | Control Group | Study Group |
|---|---|---|---|
| STARTED | 33 | 29 | 34 |
| COMPLETED | 29 | 27 | 32 |
| NOT COMPLETED | 4 | 2 | 2 |
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 | Placebo Group | Control Group | Study Group | Total |
|---|---|---|---|---|---|
| Participants analysed | 29 | 27 | 32 | 88 | |
| Age, Continuous | years | 56 (SD 0.9) | 58 (SD 0.6) | 56 (SD 0.8) | 57 (SD 0.8) |
| Sex: Female, Male: Female | Participants | 9 | 9 | 15 | 33 |
| Sex: Female, Male: Male | Participants | 20 | 18 | 17 | 55 |
| Region of Enrollment: United States | participants | 29 | 27 | 32 | 88 |
6. Primary Endpoint
The registry lists the primary outcome as Pain Scores, measured over O hour, 1, 2, 3, 4, 5, 6, 12 and 72 hours..
| Element | Registry entry |
|---|---|
| Result type | Mean |
| Measure of spread | Standard Deviation |
| Unit | mm |
| Endpoint classification | Continuous Endpoint |
The primary outcome is titled “Pain Scores.” The registry describes pain measurement using a Visual Analong Scale with a measurement range of 0-100mm, and specifies the mean and standard deviation as the summary format. The listed measurement times are O hour, 1, 2, 3, 4, 5, 6, 12 and 72 hours.
Pain scores are continuous measurements: they can take values along a scale rather than belonging only to categories such as event or no event. Reporting a mean describes the average score in a group, while a standard deviation describes how dispersed individual scores are around that mean. These are general statistical interpretations of the stated summary measures; the registry record does not report the group means or standard deviations.
Repeated measurement can describe how scores vary across the recorded postoperative time points. It also makes the analysis question more complex than a single comparison at one time: results may differ by time, and the data from the same participant may be related across measurements. The registry record lists multiple measurement times but does not report a single time point selected for a standalone comparison, a summary across time, or an analysis accounting for repeated measurements.
The registry record contains one primary outcome measure, but its several time points mean the outcome is not reduced to one reported comparison. No pain-score results, effect estimates, uncertainty intervals, or tests are reported in the registry record.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry record states the study’s null hypothesis: continuous subacromial bupivacaine infusion would provide no pain-control benefit compared with placebo infusion or no catheter use. That statement describes the research question, not the trial’s finding. The record lists the pain-score outcome and its measurement times, but reports no analyzed outcome results. There are therefore no reported group means, standard deviations, between-group estimates, confidence intervals, or p-values on which to base a statistical conclusion about the stated question.
The three-arm arrangement is important when interpreting the intended comparisons. The bupivacaine group can be contrasted with the saline-catheter group, which shares catheter use, and with the no-catheter control group. These comparisons address different contrasts: one compares the infusion contents while retaining a catheter in both groups; the other compares the complete bupivacaine-catheter approach with no continuous infusion catheter. The registry record does not report results for either contrast.
Because pain was measured at several times, a result at one time would not by itself describe the entire postoperative measurement period. A complete interpretation would need to identify which times were analyzed, how the repeated observations were handled, and whether the reported comparison was selected in advance. Those analysis details and results are not reported in the registry record. The listed time points alone do not establish that every time point was analyzed or that they were treated as equally important.
Precision also cannot be assessed from the registry record. A point estimate would describe the observed difference between groups, while a confidence interval would show the range of values compatible with the data under the analysis assumptions. Neither is reported. Without them, the record does not show whether an estimated difference was precise or uncertain, and no inference about statistical significance can be made from the listed enrollment or the null hypothesis.
The record reports zero serious adverse events and zero other adverse events in each of the three group entries. This is a description of the posted event counts, not a substitute for pain-outcome results or evidence about the magnitude of any treatment effect. Death counts are listed as null, so deaths are not reported as a count in the registry record. Further context for reading these figures appears in the safety discussion.
Overall, the registry record documents a randomized trial design and planned pain measurements but does not report analyzed pain outcomes. It therefore permits description of the trial’s question, groups, and measurement schedule, but not a conclusion about the direction, size, precision, or statistical significance of the pain-score comparisons.
9. Statistical Methods Explained
The registry identifies the study as randomized, double-masked, and parallel. In general, randomization assigns participants to trial groups using a chance-based process. It is intended to reduce systematic differences between groups at the point of allocation, although it does not guarantee that groups will be identical. The registry record does not report how the random sequence was generated, how allocation was concealed, or whether the intended allocation was balanced across the three groups.
What does double masking mean?
In general, masking is intended to limit the influence of knowing a participant’s assigned group on care, outcome assessment, or reporting. The record labels the trial double-masked, but does not identify which two groups of people were masked or describe the procedure. The no-catheter control differs visibly in whether a catheter is used, so the record would need further detail to clarify how masking applied to that comparison. No such detail is reported in the registry record.
How should the continuous outcome be summarized?
The pain endpoint is a continuous score measured on a stated 0-100mm scale. The registry specifies a mean and standard deviation. In general, a mean gives the group’s average score, and a standard deviation describes variation among measured scores. A difference in group means can summarize the contrast between groups, but it is not enough on its own: its uncertainty and the method used to estimate it matter. The registry record does not give means, standard deviations, estimated contrasts, or confidence intervals.
A confidence interval is a statistical range that conveys the uncertainty around an estimate under the assumptions of the analysis. It helps readers judge which effect sizes remain compatible with the observed data. A narrower interval indicates greater precision than a wider interval, all else equal. This is a general explanation; no confidence interval for pain scores is reported in the registry record. A p-value, when reported, addresses compatibility of the data with a specified null model under the test assumptions. It does not describe the size or clinical importance of an effect. No pain-outcome p-value is reported.
Why do the multiple time points matter?
The endpoint schedule includes O hour, 1, 2, 3, 4, 5, 6, 12 and 72 hours. In general, measurements from the same person over time may be correlated. An analysis that treats each observation as independent when observations are related can produce inappropriate uncertainty estimates. Statistical methods for repeated measurements can model that relationship, or an analysis can define a single time point or summary in advance. The registry record does not describe which approach, if any, was used.
Testing or estimating differences at multiple times also raises a multiplicity issue. In general, the more comparisons considered, the more opportunities there are to obtain a seemingly unusual result by chance if each is interpreted separately. Prespecified outcome priorities and suitable adjustment or interpretation strategies can address this concern. The record lists several times but does not report a multiplicity plan, a selected primary time point, or results across times.
What does the planning description establish?
The registry includes a sample-size planning description based on an observed effect, with 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. Such a calculation is a planning illustration, not observed power and not evidence that the study had a particular probability of detecting an effect. Because no observed pain effect or calculated sample-size result is reported in the registry record, no numerical planning estimate can be interpreted from this information. The description also refers to two-arm allocation, while the trial lists three groups; the record does not explain how that planning approach relates to the trial’s three-arm design.
In general, over-dispersion means that observed variability exceeds what a chosen statistical model assumes. When present, accounting for it can affect standard errors and confidence intervals. The registry record does not report an over-dispersion assessment or indicate that a model requiring such an assessment was used. More broadly, the statistical analysis plan, analysis population definitions, model specification, covariate adjustments, missing-data methods, and handling of protocol deviations are not reported in the registry record.
10. Multiplicity, Missing Data and Analysis Populations
The pain endpoint is measured at multiple postoperative times, so the set of possible comparisons is broader than a single comparison at a single time. The registry record does not report a multiplicity strategy, identify a selected time point for the primary analysis, or explain whether the time points were analyzed separately or jointly. Without those details, a reader cannot determine how repeated testing was handled or which comparison should be treated as primary for interpretation.
Missing-data handling is not reported in the registry record. The record does not give the number of participants with observed pain scores at each time, reasons for missing measurements, or any method used to address missing values. Enrollment of 96 is not equivalent to the number with complete outcome data. In general, missing measurements can affect both the precision and the interpretation of an estimate, particularly if the likelihood of missingness differs by group or relates to the measured outcome.
The analysis population is also not reported in the registry record. It does not state whether analyses followed randomized assignment, included only participants who received their assigned intervention, or used another definition. The record does not describe exclusions from analysis or how treatment deviations were handled.
No pain-outcome analyses are reported, and the registry lists zero analyses. Consequently, there is no stated analysis population, no reported missing-data approach, and no reported multiplicity adjustment to evaluate. These omissions limit interpretation of the endpoint beyond its stated measurement scale and schedule.
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 |
|---|---|---|---|
| Placebo Group | 0 | 33 | 0.0% |
| Control Group | 0 | 29 | 0.0% |
| Study Group | 0 | 34 | 0.0% |
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 |
|---|---|
| Placebo Group | 0 of 33 |
| Control Group | 0 of 29 |
| Study Group | 0 of 34 |
The registry lists serious adverse event counts of 0 in the placebo group, 0 in the control group, and 0 in the study group. It also lists other adverse event counts of 0 in each group. The corresponding at-risk counts are 33 for the placebo group, 29 for the control group, and 34 for the study group. These are the registry’s posted counts; they describe what is recorded, not a comparative safety analysis.
Zero recorded events does not establish that the risk of an event is zero. Event counts are interpreted in the context of how many participants were observed, how events were defined and collected, and how long follow-up lasted. The registry record does not report additional event definitions, event-collection procedures, follow-up details for safety, or a statistical comparison between groups. It also lists deaths as null in each group. A null entry is not a numerical count, so deaths are not reported as a count in the registry record.
The serious and other adverse event figures should therefore be read as descriptive registry entries. They do not provide a precise estimate of event risk, establish equivalence between groups, or answer the pain-score question.
12. What the Result Does, and Does Not, Mean
This trial record is relevant to a focused statistical question: whether postoperative pain scores differed among participants assigned to continuous subacromial bupivacaine infusion, saline infusion through a catheter, or no continuous infusion catheter. Its randomized, double-masked, parallel design and three-group structure are documented, as are the pain scale and measurement schedule.
What the record does not provide is the outcome evidence needed to quantify those comparisons. There are no reported group pain-score summaries, estimated differences, confidence intervals, or p-values. The registry record therefore does not show whether scores differed, in which direction they differed, how large any difference was, or how precisely it was estimated. The stated null hypothesis is not a result and cannot be treated as confirmation of no difference.
Even if outcome estimates were available, statistical interpretation would depend on the selected comparison, time point or longitudinal summary, analysis population, and treatment of repeated measurements and missing data. Those details are not reported in the registry record. A statistically detectable difference, in general, is not automatically a measure of clinical importance; that judgment requires contextual criteria not reported in the record.
The adverse-event entries are also limited: zero serious and zero other events are recorded for each group, while death counts are null. These descriptive entries do not establish absence of risk or provide a comparative safety estimate. The appropriate scope of interpretation is therefore narrow: the record documents the trial’s question, assigned approaches, measurement plan, and posted event counts, but does not report analyzed pain outcomes from which to assess the primary question.
13. Why This Trial Matters Statistically
Statistically, this trial is notable for distinguishing two different comparison conditions. The saline group receives a catheter like the bupivacaine group, whereas the control group receives no continuous infusion catheter. In general, comparing the active infusion with saline can help separate differences associated with the infusion contents from differences associated with having a catheter. Comparing with no catheter addresses a broader contrast between the bupivacaine-catheter approach and no continuous catheter. The registry describes both comparisons as relevant to the stated question, but reports no results for either.
The record also illustrates why an outcome schedule matters. Pain is recorded at several postoperative times, rather than at only one listed point. Repeated measurements can describe change over time, but they require a clearly stated analysis strategy and careful interpretation of multiple potential comparisons. Those statistical details are not reported in the registry record.
Another important distinction is between documenting a trial design and reporting its findings. Randomization, masking, enrollment, intervention descriptions, and outcome definitions help readers understand what was planned or conducted. They do not reveal the estimated effect. Without analyzed pain scores and uncertainty estimates, the record cannot support a statistical conclusion about the primary question.
The record is therefore useful for defining the intended comparisons and identifying information needed for interpretation. It also highlights the limits of descriptive adverse-event counts and planning assumptions when outcome analyses are absent. The central statistical lesson is that a clear design and measurement schedule do not replace transparent reporting of estimates, uncertainty, analysis methods, and missing-data handling.
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 main trial-specific limitation of the registry record is the absence of reported pain-outcome analyses. Although pain scores are identified as the primary outcome, no group summaries or between-group comparisons are reported. The record consequently offers no basis for assessing the size, direction, or precision of a pain-score difference.
The outcome has several listed time points, but the record does not identify one as the primary analysis time or explain how measurements over time were modeled. It also does not report whether multiplicity was addressed. These omissions make it difficult to know how a single interpretation would relate to the full measurement schedule.
The record lists three groups, while its planning description refers to equal allocation between two arms. It does not explain how the planning illustration was applied to the three-group trial. The observed effect referenced in the planning description is not reported alongside analyzed pain results, so the planning assumptions cannot be evaluated against an observed outcome estimate.
Additional details are not reported in the registry record: the analysis population, outcome-data completeness at each time, missing-data methods, allocation procedures, masking procedures, and statistical model. The record labels the study double-masked but does not state who was masked or explain masking for the no-catheter comparison. The safety entries provide event counts and at-risk counts, but not event definitions, collection procedures, or a comparative analysis. These limitations concern what the registry record reports; they do not establish what may have been available in other trial documents.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Post-Op Rotator Cuff Pain Study With Subacromial Bupivacaine Infusion — NCT01126593.
- Registry record last updated 2014-11-07; status last verified 2014-11.
- Results first posted 2014-11-07.
- 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
The registry record describes a completed, randomized, double-masked, parallel trial with 96 participants enrolled. The three groups are continuous subacromial infusion of 0.5% bupivacaine, a saline infusion catheter, and no continuous infusion catheter. The primary outcome is mean pain score on a 0-100mm Visual Analong Scale, measured at the listed postoperative times.
The record states a null hypothesis of no pain-control benefit for bupivacaine infusion compared with placebo infusion or no catheter use. It does not report pain-score analyses, group means, variability estimates, treatment comparisons, confidence intervals, or p-values. Serious and other adverse event counts are recorded as zero in each group; death counts are null. Missing-data handling, analysis populations, multiplicity procedures, and detailed statistical methods are not reported in the registry record.