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 A Study to Compare the Effectiveness of Adductor Canal Pain Catheters Following Total Knee Arthroplasty (NCT05053087), a randomized phase 3 study. The primary outcome is Post-operative Pain Levels.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT05053087 |
| Phase | Phase 3 |
| Condition | Osteoarthritis, Knee |
| Allocation | Randomized |
| Design model | Parallel |
| Masking | Double |
| Enrollment | 60 |
| Arms in the primary outcome | 3 |
| Lead sponsor | Mayo Clinic |
| Results posted | Yes |
2. Clinical Question
Population
The registry lists osteoarthritis of the knee as the condition and describes patients undergoing total knee arthroplasty. The study enrolled 60 participants. The registry does not report further eligibility criteria, such as age limits, disease severity requirements, or exclusions, so the population represented by the results cannot be defined more narrowly from this record.
Intervention
One study arm received ropivacaine 0.2% through a catheter as a continuous infusion. Another received ropivacaine 0.2% through a catheter as pulsed intermittent boluses. The descriptions state that the catheters were placed in the Post Anesthesia Care Unit following surgery. The registry does not report the administered dose or detailed delivery schedule.
Comparator
The comparator arm is titled Single Shot Adductor Canal. Its arm description says that a catheter was placed following surgery and saline was administered. The study summary describes comparison with a single-shot adductor canal block. These descriptions identify the registry’s comparator, but the record does not provide further procedural detail about how the comparator was delivered.
Primary question
The primary outcome was patient-reported pain intensity on the Visual Analogue Scale, rated from 0 to 10, at 14 days post-operatively. The score’s endpoints are described as 0 for no pain and 10 for the worst pain imaginable. The clinical question is whether the observed pain-score distributions differed across the three randomized arms. The registry reports arm-level medians and full ranges, but does not report a statistical test or estimated between-arm effects.
3. Trial Design
The registry describes a phase 3, randomized, double-blinded, parallel-group trial comparing three approaches to adductor canal pain management after total knee arthroplasty. The three arms were ropivacaine continuous infusion, ropivacaine intermittent bolus, and the Single Shot Adductor Canal comparator. The registry lists an enrollment of 60 and records the study as completed. Mayo Clinic is named as the sponsor.
The study began on 2022-04-13, and the primary completion date was 2023-02-27. The arm-level outcome record lists 21 participants for the Single Shot Adductor Canal arm, 20 for the Ropivacaine Continuous arm, and 19 for the Ropivacaine Intermittent Bolus arm. These are the counts reported with the outcome results. The registry does not explain any difference between the overall enrollment and the arm-level outcome counts.
Double masking is recorded, but the registry does not say which groups of people were masked or how masking was maintained. Details of sequence generation, allocation concealment, the randomization ratio, and any stratification are not reported in the registry record. Nor does the record provide a fuller account of the surgery, post-operative care, or co-interventions. The arm descriptions say that catheters were placed in the Post Anesthesia Care Unit following clinically indicated surgery.
The primary outcome was post-operative pain levels, assessed 14 days after surgery. Secondary outcomes listed in the registry were amount of medication administered and duration of narcotic used. The posted results include arm-level results for the primary outcome and adverse-event counts. The registry does not report results for the secondary outcomes, or analyses comparing the randomized 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 | Single Shot Adductor Canal | Ropivacaine Continuous | Ropivacaine Intermittent Bolus |
|---|---|---|---|
| STARTED | 21 | 20 | 19 |
| COMPLETED | 21 | 20 | 19 |
| NOT COMPLETED | 0 | 0 | 0 |
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 | Single Shot Adductor Canal | Ropivacaine Continuous | Ropivacaine Intermittent Bolus | Total |
|---|---|---|---|---|---|
| Participants analysed | 21 | 20 | 19 | 60 | |
| Age, Continuous | years | 75 (52 to 81) | 71 (49 to 80) | 70 (52 to 79) | 72 (49 to 81) |
| Sex: Female, Male: Female | Participants | 15 | 7 | 12 | 34 |
| Sex: Female, Male: Male | Participants | 6 | 13 | 7 | 26 |
| Race (NIH/OMB): American Indian or Alaska Native | Participants | 0 | 0 | 0 | 0 |
| Race (NIH/OMB): Asian | Participants | 0 | 0 | 0 | 0 |
| Race (NIH/OMB): Native Hawaiian or Other Pacific Islander | Participants | 0 | 0 | 0 | 0 |
| Race (NIH/OMB): Black or African American | Participants | 0 | 0 | 0 | 0 |
| Race (NIH/OMB): White | Participants | 18 | 19 | 18 | 55 |
| Race (NIH/OMB): More than one race | Participants | 0 | 0 | 0 | 0 |
| Race (NIH/OMB): Unknown or Not Reported | Participants | 3 | 1 | 1 | 5 |
| Region of Enrollment: United States | participants | 21 | 20 | 19 | 60 |
6. Primary Endpoint
The registry lists the primary outcome as Post-operative Pain Levels, measured over 14 days post-operatively.
| Element | Registry entry |
|---|---|
| Result type | Median |
| Measure of spread | Full Range |
| Unit | score on a scale |
| Endpoint classification | not reduced to a single comparison |
The primary endpoint is the patient’s self-reported pain intensity on the Visual Analogue Scale (VAS), assessed 14 days post-operatively. The scale is described as ranging from 0 to 10, where 0 means no pain and 10 means the worst pain imaginable. A VAS score records a patient’s rating of pain at the specified assessment time; it is not a measure of medication use or duration of narcotic use.
Pain scores are clinically relevant to this study because the trial compares approaches intended to provide pain control after total knee arthroplasty. A patient-reported measure captures the patient’s own assessment rather than relying only on an observer’s judgment. The registry specifies a single assessment timeframe for the primary endpoint, so the posted result concerns reported pain at 14 days post-operatively, not the full course of pain after surgery.
The registry reports the median and full range for each arm. A median describes the middle of the ordered observations, while the full range gives the lowest and highest observed values. The range is not a confidence interval and does not, by itself, quantify uncertainty in an estimated difference between arms. The record does not report individual scores, a standard deviation, or a between-arm effect estimate for this endpoint.
The registry lists amount of medication administered and duration of narcotic used as secondary outcomes, but their results are not reported in the registry record. Therefore, the posted primary outcome should be interpreted as a pain-score summary at the stated assessment, not as a complete account of pain or medication use over time.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The posted primary outcome summaries are medians with full ranges at 14 days post-operatively. The Single Shot Adductor Canal arm had a median score of 5.1, with a full range from 1.7 to 7.9. The Ropivacaine Continuous arm also had a median of 5.1, with a full range from 3.1 to 8.3. The Ropivacaine Intermittent Bolus arm had a median of 6.1, with a full range from 1.9 to 8.0. These are descriptive results for the recorded arms, not estimates of the effect of one approach relative to another.
The reported ranges overlap. A range describes the observed spread between the lowest and highest recorded scores; it does not show how many participants had scores at particular points within that span. Nor does overlap or non-overlap between ranges constitute a formal statistical test. The medians offer a concise description of the center of each arm’s recorded scores, but do not show the shape of the distributions or the uncertainty around the medians.
The registry lists outcome counts of 21, 20, and 19 for the comparator, continuous infusion, and intermittent bolus arms, respectively. These counts identify the participants associated with the posted outcome summaries. The registry does not explain the analysis population, the handling of missing assessments, or why arm-level outcome counts differ from the overall enrollment entry. It is therefore not possible to determine from the record whether the summaries include every randomized participant or how incomplete data were handled.
No statistical analysis results are posted in the registry record: the record lists zero analyses. It does not report a test of the three-arm comparison, pairwise tests, adjusted estimates, confidence intervals, or p-values. Consequently, the descriptive medians cannot establish whether observed differences are compatible with chance variation or whether they are precise. The absence of a reported comparison is not evidence that the arms are equivalent, and it does not establish that any approach is superior.
The study’s listed secondary outcomes concern medication administered and duration of narcotic use. Results for those outcomes are not reported in the registry record. The primary endpoint therefore provides only the stated pain-score summaries at the 14-day assessment; it cannot answer questions about medication consumption or the duration of narcotic use. Interpretation should remain within these outcome and reporting limits.
9. Statistical Methods Explained
The statistical information in the registry is limited to descriptive summaries for the primary endpoint and counts for adverse events. The record identifies the study as randomized, double-blinded, and parallel-group, but does not describe the statistical analysis plan. The explanations below distinguish what the posted summaries mean from what would require additional analysis.
What does a median describe?
A median is a measure of the center of a distribution. After observations are ordered, the median marks the middle of the observed values. It can be useful when a score distribution is skewed or contains unusual values, because extreme observations have less influence on the median than on the mean. A median does not describe how tightly values cluster around the center. For that, readers need information about the distribution or an appropriate measure of spread.
The registry reports the full range alongside each median. The range identifies the lowest and highest observed scores. It is sensitive to observations at the extremes and does not show the frequency of scores across the interval. These ranges are descriptive summaries, not confidence intervals. A confidence interval is a general statistical tool for expressing uncertainty around an estimated quantity; no confidence interval for the pain-score medians or between-arm effects is reported in the registry record.
How should the three arms be compared?
Randomization is intended, in general, to make assigned groups comparable on average at the start of a trial. The record identifies random assignment but does not report details of the allocation process or baseline characteristics. A direct comparison would require an analysis suited to the outcome, the trial design, and the planned comparison. The registry does not report which method, if any, was used to compare pain scores across the three arms.
There are several possible questions within a three-arm design: an overall question about whether results differ among the arms, or specific pairwise questions comparing one arm with another. The record does not identify a statistical test, an estimand, or a prespecified contrast. It also does not report adjustment for baseline values or other covariates. Without those details and the associated estimates, the medians should be read as arm-level descriptions, not as adjusted treatment effects.
Why does the outcome distribution matter?
Statistical methods should reflect how the outcome is measured and how its values are distributed. A pain rating on a bounded scale cannot take values outside the stated endpoints. If observations cluster or vary more than a chosen model expects, standard errors and resulting uncertainty estimates can be unreliable. In general, over-dispersion means that observed variation is greater than a model assumes; a suitable method may need to account for it. The registry does not report a fitted model, distributional checks, or whether over-dispersion was assessed.
Because only medians and ranges are posted, readers cannot assess the detailed score distribution from the registry summary alone. The underlying scores and a description of any model are not reported in the registry record. No new statistical comparison can be recovered from the reported summaries without making assumptions that the record does not establish.
What do the planning assumptions mean?
The registry’s planning illustration is described as a calculation based on the observed effect, rather than the trial’s own design. Its stated assumptions are a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. The target effect is described as a stated fraction of the observed effect. For time-to-event outcomes, the illustration is described as reporting the total number of events using the Schoenfeld method; other outcomes are described as reporting participants per arm.
Such calculations are planning illustrations, not evidence about the trial’s observed precision and not observed power. A sample-size calculation depends on assumptions about the effect to be detected and the design; changing those assumptions changes the planning result. The registry record does not report a sample-size justification for the original trial or a detailed account of its planned statistical analysis. No planning values beyond the stated assumptions are reported in the registry record.
What is not available for independent checking?
The registry does not report a protocol or statistical analysis plan in the record summarized by these results. It gives no inferential results, missing-data method, or analysis-population definition. Individual-level outcome data, baseline values, and detailed outcome distributions are also not reported in the registry record. As a result, it is not possible to reproduce a between-arm analysis or check whether it followed a prespecified plan. The posted figures support descriptive reading only.
10. Multiplicity, Missing Data and Analysis Populations
The study has a primary pain-score endpoint and lists two secondary outcomes: amount of medication administered and duration of narcotic used. The registry does not report results for those secondary outcomes. It also does not explain whether the statistical plan accounted for testing multiple outcomes or multiple comparisons among the three arms. This is important because conducting several tests can increase the chance of at least one apparently notable result arising by chance. That general concern does not establish what happened in this trial; the multiplicity plan is not reported in the registry record.
The registry lists no analysis results. It does not report whether the primary endpoint was tested as an overall three-arm comparison, through pairwise comparisons, or by another approach. No p-values, confidence intervals, or adjusted estimates are posted. Without the analysis plan and results, readers cannot assess how multiplicity was handled or whether any comparison was designated as primary.
Missing-data procedures are also not reported in the registry record. The arm-level outcome counts are 21, 20, and 19, while overall enrollment is listed as 60. The record does not explain the relationship between those counts, whether any assessments were missing, or how missing observations were handled. It does not identify an intention-to-treat, per-protocol, or other analysis population. These omissions limit interpretation of the outcome summaries, because the included participants and the treatment of unavailable scores can affect what an analysis represents.
Randomization and double masking are recorded, but allocation concealment, the people masked, and any departures from assigned treatment are not described. The record also does not report an interim-analysis plan. These methods details should not be inferred from the trial’s design labels alone.
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 |
|---|---|---|---|
| Single Shot Adductor Canal | 0 | 21 | 0.0% |
| Ropivacaine Continuous | 0 | 20 | 0.0% |
| Ropivacaine Intermittent Bolus | 0 | 19 | 0.0% |
Deaths
| Arm | Deaths (participants affected of at risk) |
|---|---|
| Single Shot Adductor Canal | 0 of 21 |
| Ropivacaine Continuous | 0 of 20 |
| Ropivacaine Intermittent Bolus | 0 of 19 |
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 |
|---|---|
| Single Shot Adductor Canal | 0 of 21 |
| Ropivacaine Continuous | 3 of 20 |
| Ropivacaine Intermittent Bolus | 2 of 19 |
Most frequent non-serious adverse event terms
| Event term | Organ system | Single Shot Adductor Canal | Ropivacaine Continuous | Ropivacaine Intermittent Bolus |
|---|---|---|---|---|
| Catheter removed early | Surgical and medical procedures | 0 of 21 | 2 of 20 | 1 of 19 |
| Catheter placed incorrectly | Surgical and medical procedures | 0 of 21 | 0 of 20 | 1 of 19 |
| Fever | General disorders | 0 of 21 | 0 of 20 | 1 of 19 |
| Knew swelling | Musculoskeletal and connective tissue disorders | 0 of 21 | 1 of 20 | 0 of 19 |
| Knee bruising | Musculoskeletal and connective tissue disorders | 0 of 21 | 1 of 20 | 0 of 19 |
The registry reports serious adverse events, other adverse events, and deaths by arm. Serious adverse events affected 0 participants in the Single Shot Adductor Canal arm, with 21 at risk; 0 in the Ropivacaine Continuous arm, with 20 at risk; and 0 in the Ropivacaine Intermittent Bolus arm, with 19 at risk. Deaths were reported as 0 in each arm.
For other adverse events, the registry reports 0 affected among 21 at risk in the Single Shot Adductor Canal arm, 3 affected among 20 at risk in the Ropivacaine Continuous arm, and 2 affected among 19 at risk in the Ropivacaine Intermittent Bolus arm. These are the counts recorded for the listed categories; the record does not provide a fuller account of event types or severity for the other adverse events.
Zero reported serious adverse events means that none were recorded in these arm-level results. It does not show that an event is impossible, and it does not establish that the arms have identical safety profiles. The registry record does not report event definitions, monitoring procedures, follow-up details for safety, or an inferential comparison of adverse-event rates. The counts are descriptive and should be interpreted within those reporting limits.
12. What the Result Does, and Does Not, Mean
The registry results describe a randomized, double-blinded, three-arm comparison of catheter-based pain-management approaches after total knee arthroplasty. For the primary outcome, the record reports the median pain score and full range at 14 days post-operatively for each arm. The medians were 5.1 for Single Shot Adductor Canal, 5.1 for Ropivacaine Continuous, and 6.1 for Ropivacaine Intermittent Bolus. The listed ranges show the span of recorded scores within each arm, not uncertainty around a treatment effect.
These summaries do not establish that the approaches differ, or that they are equivalent. No statistical comparison, confidence interval, or p-value is reported in the registry record. Without those inferential results, the observed summaries do not quantify how precisely the arms differ or whether observed variation could account for the pattern. They should not be interpreted as proof for or against a treatment effect.
The posted results also do not answer every outcome question named in the study record. Amount of medication administered and duration of narcotic used are listed as secondary outcomes, but their results are not reported in the registry record. The primary pain measure is a self-reported score at one stated post-operative assessment; it does not describe pain at every point after surgery or provide a full account of medication use.
The adverse-event counts provide another descriptive view, with no serious adverse events or deaths reported in the listed arms and other adverse events reported in two arms. Those counts do not replace a detailed safety analysis, which would need fuller definitions, follow-up information, and comparative methods. Overall, the record gives a limited set of descriptive results. Important details about the statistical plan, missing data, analysis populations, and inferential comparisons are not reported in the registry record.
13. Why This Trial Matters Statistically
This trial is statistically interesting because it places three delivery approaches within a randomized, double-blinded, parallel-group design and focuses on a patient-reported outcome after surgery. A three-arm design can address more than a single contrast, but interpretation depends on knowing which comparisons were planned and how they were analyzed. The registry identifies the arms and reports their pain-score summaries, while leaving the inferential strategy unreported.
The primary outcome is summarized using medians and full ranges. Those summaries are useful for describing the observed scores, particularly when the distribution may not be well represented by a mean alone. At the same time, they do not quantify uncertainty around differences between arms. This distinction matters: descriptive summaries can show the recorded pattern, while an inferential analysis is needed to estimate comparative effects and their precision.
The registry also illustrates why transparency about missing data and analysis populations is important. Enrollment is recorded as 60, while the outcome counts differ by arm. The record does not explain the relationship or state how missing outcome data were handled. Without that information, readers cannot tell precisely which population the medians represent or assess the effect of missing observations.
Finally, the listed secondary outcomes and adverse-event counts have different roles from the primary pain endpoint. A complete interpretation would depend on the planned outcome hierarchy, multiplicity approach, and fuller reporting of results. Those details are not reported in the registry record. The statistical significance of this trial record therefore lies as much in recognizing what its descriptive results can support as in identifying the questions that remain unanswered.
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 a statistical analysis plan, a protocol, or inferential results for the primary endpoint. It gives no between-arm estimates, confidence intervals, or p-values. The posted medians and ranges are therefore insufficient to determine the precision of comparative effects or to assess whether any observed pattern is consistent with chance variation.
Further limitations concern the outcome data and analysis population. The record does not explain why the arm-level outcome counts differ from the overall enrollment entry, whether assessments were missing, or how any missing values were handled. It does not define the population included in the primary analysis. Baseline characteristics are not reported in the results summarized in the registry record, so the groups’ starting characteristics cannot be assessed from these data.
Details about the study procedures and masking are also limited. The record labels the trial double-blinded but does not identify who was masked or describe how masking was maintained. It does not report the randomization sequence method, allocation concealment, treatment adherence, or deviations from assigned interventions. Dose and detailed delivery schedules for the ropivacaine arms are not reported in the registry record.
Only the primary endpoint summaries and adverse-event counts are available in the posted results. The listed secondary outcomes—amount of medication administered and duration of narcotic used—have no reported results. The adverse-event record does not provide event definitions or detailed descriptions of the other adverse events. These gaps restrict interpretation of both efficacy-related outcomes and safety information to the limited descriptive data reported.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: A Study to Compare the Effectiveness of Adductor Canal Pain Catheters Following Total Knee Arthroplasty — NCT05053087.
- Registry record last updated 2024-02-22; status last verified 2024-02.
- Results first posted 2024-02-22.
- 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.
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18. Record Summary
The registry describes NCT05053087, a phase 3 randomized, double-blinded, parallel-group trial sponsored by Mayo Clinic. It studied pain-catheter approaches following total knee arthroplasty in patients with osteoarthritis of the knee. Enrollment is recorded as 60, and the study status is completed. The recorded start date is 2022-04-13, with primary completion on 2023-02-27.
The three arms were Ropivacaine Continuous, Ropivacaine Intermittent Bolus, and Single Shot Adductor Canal. The primary outcome was self-reported VAS pain at 14 days post-operatively, summarized by median and full range. The registry lists amount of medication administered and duration of narcotic used as secondary outcomes, but their results are not reported in the registry record. No statistical analysis results are posted. The available primary outcome and safety information is descriptive.