Liposomal Bupivacaine After Arthroscopic Rotator Cuff Repair: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Liposomal Bupivacaine After Arthroscopic Rotator Cuff Repair (NCT03149887), a randomized phase 4 study. The primary outcome is Numeric Rating Pain Score [NRS] at Time of Block Resolution.

2. Clinical Question

3. Trial Design

The registry record describes a completed Phase 4 randomized controlled trial of liposomal bupivacaine for postoperative pain management after arthroscopic rotator cuff repair. It lists a parallel-group design and quadruple masking. The record identifies Steven Orebaugh as the sponsor and lists 54 enrolled participants. The recorded start was 2017-12-05 and primary completion was 2019-02-26.

Participants were assigned to an experimental arm receiving liposomal bupivacaine or a control arm receiving placebo. In both descriptions, the solution was injected into the surgical field at the end of the arthroscopic repair. The brief summary describes the comparison as standard care plus liposomal bupivacaine versus standard care in the control group. The registry record does not specify the details of standard care beyond this description.

The primary outcome was a mean numeric rating pain score at the time of nerve block resolution. The registry describes the score as reported by patients at a 24-hour follow-up phone call. Results are posted for 27 participants in each arm. The record also lists seven secondary outcomes: pain at rest on postoperative days 1, 2 and 3; pain with motion; and oral analgesic requirements on postoperative days 1, 2 and 3. Results are posted for the three pain-at-rest outcomes. The other secondary outcomes are not included among the posted results. The record does not report further details about randomization procedures, allocation concealment, or the masking procedures.

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

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 Numeric Rating Pain Score [NRS] at Time of Block Resolution, measured over At the time of block resolution, as reported by patients at follow up phone call.

The primary endpoint is the mean Numeric Rating Scale pain score at the time of nerve block resolution. The registry describes a scale from 0 to 10: zero means no pain, while 10 means very severe pain. Patients reported their score at the time of block resolution during a follow-up phone call described as occurring at 24 hours. The outcome is the mean of the participants’ reported scores.

A pain score is a continuous measure when analyzed as a numeric value. Comparing group means gives an estimate of the average difference between the trial arms on this scale. The endpoint is intended to capture pain at a clinically relevant transition point: resolution of the nerve block. That timing is part of the endpoint definition and should be kept in mind when interpreting the result; it is not a measure of pain across the entire postoperative period.

The registry does not report a threshold for a difference that would be considered important to patients, nor does it explain why this endpoint was selected over other possible pain assessments. Accordingly, the result describes the mean scores and their statistical uncertainty, but does not by itself establish the importance of any observed difference.

7. Results Posted in the Registry

• Experimental (Liposomal Bupivacaine): mean 5.40 versus 5.80 on control; difference -0.40 (95% CI -1.96 to 1.16), standardized effect d = -0.14; z-test p = 0.614.

8. Secondary Efficacy Endpoints

The registry also posts results for secondary outcomes. For each outcome below, the endpoint type, the test applied to the posted summary statistics, the result and its interpretation are given in turn. Secondary endpoints are usually not adjusted for multiple testing, so they support rather than confirm the primary finding.

Mean NRS Pain Score at Rest on Postoperative Day 1

• Endpoint type: Continuous: a mean value per participant, compared as a difference in means.
• Test: Unadjusted two-sample z-test for the difference in means, using the posted standard deviations.
• Result:
  • Experimental (Liposomal Bupivacaine): mean 5.70 versus 6.10 on control; difference -0.40 (95% CI -1.75 to 0.95), standardized effect d = -0.16; z-test p = 0.563.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between Experimental (Liposomal Bupivacaine) and the control. The interval gives the range of effects that remain compatible with the data.

Mean NRS Pain Score at Rest on Postoperative Day 2

• Endpoint type: Continuous: a mean value per participant, compared as a difference in means.
• Test: Unadjusted two-sample z-test for the difference in means, using the posted standard deviations.
• Result:
  • Experimental (Liposomal Bupivacaine): mean 5.20 versus 6.40 on control; difference -1.20 (95% CI -2.49 to 0.09), standardized effect d = -0.51; z-test p = 0.068.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between Experimental (Liposomal Bupivacaine) and the control. The interval gives the range of effects that remain compatible with the data.

Mean NRS Pain Scores at Rest on Postoperative Day 3

• Endpoint type: Continuous: a mean value per participant, compared as a difference in means.
• Test: Unadjusted two-sample z-test for the difference in means, using the posted standard deviations.
• Result:
  • Experimental (Liposomal Bupivacaine): mean 4.60 versus 6.30 on control; difference -1.70 (95% CI -2.78 to -0.62), standardized effect d = -0.87; z-test p = 0.002.
• Interpretation:
  • The 95% confidence interval excludes no difference, so the mean is statistically lower for Experimental (Liposomal Bupivacaine) than for the control. This is an unadjusted, secondary comparison, so it is suggestive rather than confirmatory.

Across the three posted pain-at-rest outcomes, mean scores were lower in the liposomal bupivacaine arm than in the control arm. The estimates varied in size and precision across postoperative days, so the overall pattern is not a single uniform measure of effect. These results concern separate time points and should be read as a set of related observations, rather than as independent confirmation of the primary endpoint.

The primary endpoint concerns pain at nerve block resolution, while the secondary pain scores concern rest pain on postoperative days 1, 2 and 3. The secondary results therefore add information about pain at later specified times, but they do not change the uncertainty in the primary comparison. The registry also lists pain with motion and oral analgesic requirements on postoperative days 1, 2 and 3; results for those outcomes are not reported in the registry record.

The registry lists eight outcomes and eight analyses, but does not report a multiplicity adjustment. General statistical context: when several outcomes are tested, some apparently notable results can arise by chance even if no underlying effect exists. Unadjusted secondary p-values consequently carry less weight than a prespecified primary result, particularly when the analysis plan and hierarchy among outcomes are not available. The secondary findings can be treated as suggestive patterns that may inform future questions, but the registry record does not establish that they were confirmatory tests.

The varying numbers contributing to the posted outcomes also matter when comparing time points. The primary results include 27 participants per arm, while the posted day-specific results include 26 participants in the experimental arm and 25 in control. The record does not explain why the analysis counts differ or how missing observations were handled. That uncertainty limits conclusions about whether the pattern reflects complete follow-up or a subset of participants.

Secondary outcomes registered for this trial, for reference (only those above were recalculated):

• Mean NRS Pain Score at Rest on Postoperative Day 1
• Mean NRS Pain Score at Rest on Postoperative Day 2
• Mean NRS Pain Scores at Rest on Postoperative Day 3
• Mean NRS Pain Score With Motion
• Oral Analgesic Requirements on Postoperative Day 1
• Oral Analgesic Requirements on Postoperative Day 2
• Oral Analgesic Requirements on Postoperative Day 3

9. Statistical Interpretation

10. Statistical Methods Explained

For a continuous outcome, a group mean describes the average observed score among participants with posted data. The standard deviation describes how much individual scores vary around that mean. In the primary results, the mean and standard deviation are reported for each arm, along with the number of participants contributing to the outcome. These summaries make it possible to describe both the average pain score and the spread of scores within each group.

What the mean difference represents

The comparison is expressed as the experimental-group mean minus the control-group mean. A negative estimate therefore means the observed mean was lower in the experimental arm. The primary estimate is -0.4. This is a difference in scale points, not a percentage change and not a measure of the proportion of participants who experienced a particular level of pain. A difference between group averages also does not describe how much the scores of individual participants overlap.

The recalculated comparison is unadjusted: it uses the posted summary statistics rather than participant-level records or adjustment for additional variables. A t-test compares group means while accounting for the observed variation and sample sizes. The registry reports a two-sided t-test for the primary analysis. A two-sided test considers departures in either direction rather than testing only whether one arm has a lower mean.

How to read a p-value

A p-value describes how unusual data at least as incompatible with a specified no-difference model would be under the assumptions of the test. It is not the probability that the no-difference model is true, nor is it a direct measure of effect size. The registry’s primary p-value is 0.66; the recalculated unadjusted p-value is 0.614. These should be considered alongside the estimated difference and its interval. A result that does not give strong evidence against a no-difference model does not prove that the group means are identical.

There is no reported equivalence margin or non-inferiority margin. Without such a prespecified margin, a non-significant comparison cannot be treated as evidence that the treatments are equivalent. Equivalence questions require a different interpretation: the uncertainty interval must be judged against a defined range of differences that would count as acceptably small. That range is not reported in the registry record.

What an interval adds

A confidence interval represents uncertainty around an estimated difference under the statistical method used. Narrower intervals indicate greater precision, while wider intervals leave more possible values compatible with the data. The primary interval, -1.955 to 1.155, includes zero and reaches in both negative and positive directions. It therefore does not isolate a single direction of difference. The registry does not state the confidence level for this interval, so no confidence percentage should be attributed to it based on this record alone.

General statistical context: intervals are most useful when interpreted in relation to both zero and a clinically meaningful threshold. The registry provides no threshold for a meaningful score difference. Consequently, the interval can be described statistically, but the record alone cannot determine whether any particular value within it would matter to patients.

Why variation and sample size matter

General statistical context: the precision of a mean comparison depends on the amount of variation in scores and on how many observations contribute. Greater variability makes it harder to distinguish a group difference from random fluctuation; more observations can improve precision when other conditions are similar. The primary outcome includes 27 participants per arm, and the reported standard deviations are 2.6 and 3.2. The resulting interval remains wide enough to cover differences in either direction.

The t-test is a method for comparing means. Its interpretation relies on assumptions about the data and the analysis, including how observations are sampled and whether the model is suitable for the outcome distribution. The registry identifies the test but does not report diagnostic checks, transformations, covariate adjustment, or other details of the statistical model. No further assessment of those choices can be made from the registry record.

Recalculation and sponsor analysis

The recalculated estimate and interval are derived from the posted group summaries and represent a simple unadjusted calculation. The sponsor’s recorded analysis reports a two-sided t-test p-value but does not provide its own estimate or interval in the registry results. Because the record does not indicate a discrepancy, the two sets of p-values can be described together without treating the recalculation as a correction of the sponsor’s result. The sponsor’s reported analysis remains the trial’s own inferential analysis.

General statistical context: a summary-statistic recalculation may not reproduce an analysis based on individual participant data, especially if the original analysis used adjustments, a different handling of missing observations, or a different variance method. The registry record does not report whether any such choices were made. The recalculation should therefore be read as a transparent, unadjusted companion to the posted summaries, not as a reconstruction of every element of the original analysis.

Multiplicity and the wider analysis set

The registry lists eight outcome measures and eight analyses. Repeated testing across outcomes can increase the chance that at least one comparison appears unusually strong by chance, if each is interpreted without accounting for the set of tests. General statistical context: multiplicity procedures adjust the interpretation or testing threshold to account for a collection of comparisons. The registry record does not report whether a correction was planned or applied, so the secondary p-values should be regarded as unadjusted unless the record states otherwise.

The registry does not report the original statistical analysis plan, sample-size justification, interim analyses, or analysis-population definition. These are not details that can be inferred from the posted group summaries. In particular, the planning illustrations based on observed effects are not evidence of the trial’s original design assumptions or of the power the completed trial achieved.

11. Confidence Intervals and Precision

The primary mean difference is -0.4, with an interval from -1.955 to 1.155. The interval crosses zero, so the data are compatible with a lower mean score in the experimental arm, a difference close to zero, and a higher mean score in that arm. Its width indicates that the estimate is not precise enough to settle the direction of the difference. The interval is more informative than the point estimate alone because it conveys how much uncertainty remains around the observed comparison.

The two arm means are 5.4 and 5.8, with standard deviations of 2.6 and 3.2, based on 27 participants in each arm. The standard deviations describe variation among participants; they are not uncertainty intervals for the group means. The comparison interval instead concerns the estimated difference between the group means. These quantities answer different questions and should not be substituted for one another.

The registry does not report the confidence level attached to the interval. It also does not report a threshold for a clinically important difference on the 0-to-10 scale. Thus, the interval can be used to understand statistical uncertainty but cannot be classified against a registry-defined threshold of patient importance. It does not show that the groups are equivalent, and the absence of a clear difference is not proof that no difference exists.

General statistical context: precision is affected by sample size and variability, among other features of a study and its analysis. The primary outcome has 27 participants per arm, and the interval remains compatible with effects in either direction. More precise estimates would generally require more information, but the registry record does not specify the target precision or a planned clinically meaningful effect.

12. Planning a Similar Trial: Sample Size

This is a planning illustration, not a re-evaluation of the original trial. It asks: if a new study wanted to detect a difference like the one observed, or a smaller one, how large would it need to be? It is deliberately not “observed power” of the finished trial, which is not a meaningful quantity.

The planning illustrations give participants per arm for 80% power and participants per arm for 90% power. They are not total sample sizes and are not total event counts; the outcome is continuous, so these entries are participant counts per arm. For the primary endpoint, the illustration based on 100% of the observed effect gives 834 participants per arm for 80% power and 1,117 participants per arm for 90% power. Planning for 75% of the observed effect gives 1,483 participants per arm for 80% power and 1,985 participants per arm for 90% power. Planning for 50% of the observed effect gives 3,336 participants per arm for 80% power and 4,466 participants per arm for 90% power.

The stated planning assumptions are a two-sided significance level of 0.05, equal allocation between the two arms, and a normal approximation. The effect used for planning is the stated fraction of the observed effect. The illustrations use the observed effect as an input; they are not the trial’s original design calculation. The trial’s own sample-size assumptions and justification are not reported in the registry record.

In general, the 80% power column gives a planning count for a design intended to have an 80% chance of detecting the specified effect under the stated assumptions if that effect is present. The 90% column represents a higher planned chance of detecting that effect and therefore calls for more participants under these assumptions. Smaller effects are harder to distinguish from random variation and require more participants. These figures are planning illustrations, not observed power.

13. How the Sample Size Is Derived

Power is the probability that a study of a given size rejects the null hypothesis when a specific true effect exists. It depends on four things: the effect to detect, the variability of the outcome, the significance level (here a two-sided α of 0.05, so z_1−α/2 = 1.960) and the desired power (z_1−β = 0.842 for 80% and 1.282 for 90%).

Formula

n is the number of participants in each arm, Δ is the difference in means to detect and σ is the common standard deviation.

Worked calculation for this trial

1. Observed difference Δ = -0.400; pooled standard deviation σ = 2.915.
2. n = 2 × (1.96 + 0.842)² × 2.915² / -0.400² = 833.9, rounded up to 834 participants per arm for 80% power.

The smaller-effect rows in the table above repeat the same calculation with the effect multiplied by 0.75 and 0.5 (for ratios, applied to the logarithm of the ratio).

R code

alpha <- 0.05
z_a   <- qnorm(1 - alpha / 2)          # two-sided
delta <- -0.399999999999999                      # observed difference in means
sigma <- 2.91547594742265                     # pooled standard deviation
n_per_arm <- function(power, frac = 1) {
  ceiling(round(2 * (z_a + qnorm(power))^2 * sigma^2 / (delta * frac)^2, 6))
}
for (f in c(1, 0.75, 0.5))
  cat(sprintf("%3.0f%% of observed effect: n per arm = %s (80%% power), %s (90%% power)\n", 100 * f,
              format(n_per_arm(0.80, f), big.mark = ","), format(n_per_arm(0.90, f), big.mark = ",")))

# Check against R's built-in function (t-based, so very slightly larger)
cat("power.t.test:", round(power.t.test(delta = delta, sd = sigma, power = 0.80)$n, 1), "\n")

# Simulation: exact two-sample t-test using simulated means and variances
set.seed(3149887)
n    <- n_per_arm(0.80)
reps <- 20000
m_diff <- rnorm(reps, delta, sigma * sqrt(2 / n))             # difference in sample means
s2     <- sigma^2 * rchisq(reps, 2 * (n - 1)) / (2 * (n - 1))   # pooled sample variance
tstat  <- m_diff / sqrt(s2 * 2 / n)
cat(sprintf("Simulated power at n = %s per arm: %.3f (%d replicates)\n", format(n, big.mark = ","), mean(abs(tstat) > qt(0.975, 2 * (n - 1))), reps))

Output from running the code

100% of observed effect: n per arm = 834 (80% power), 1,117 (90% power)
 75% of observed effect: n per arm = 1,483 (80% power), 1,985 (90% power)
 50% of observed effect: n per arm = 3,336 (80% power), 4,466 (90% power)
power.t.test: 834.9 
Simulated power at n = 834 per arm: 0.804 (20000 replicates)

The simulation draws many sets of group means and variances at the planned sample size and counts how often the two-sample t-test rejects the null. It should land close to the target power; at very small required sample sizes it can fall below it, because the normal approximation is rough there.

14. Analyses Reported by the Sponsor

The registry reports the sponsor’s primary analysis as a two-sided t-test with p = 0.66. The simple unadjusted recalculation from the posted group summaries gives p = 0.614, alongside a recalculated mean difference of -0.4 and an interval from -1.955 to 1.155. The registry does not flag a discrepancy between the sponsor analysis and the recalculation.

The sponsor’s reported p-value is the trial’s own inferential result. The recalculated result is a companion analysis based on the posted means, standard deviations, and group sizes; it does not replace or correct the sponsor’s analysis. The record does not provide the sponsor’s estimated difference or interval, and it does not report whether the sponsor’s test used additional adjustments or other analytic choices.

The two p-values are close in interpretation: neither gives strong evidence against a no-difference model. They should not be read as proof of equivalence or as a measure of the size or importance of any difference. The group means and the recalculated interval help describe direction and precision, while the sponsor’s reported test documents the trial’s own analysis.

15. Multiplicity, Missing Data and Analysis Populations

The registry record lists eight outcome measures and eight analyses. It reports one primary endpoint and seven secondary outcomes, but does not provide an analysis plan describing outcome hierarchy, testing order, or control of the overall chance of false-positive findings. A multiplicity adjustment is not reported in the registry record.

General statistical context: testing multiple outcomes creates a collection of opportunities to observe an apparently unusual result by chance. If each result is interpreted separately without accounting for the full set, the overall false-positive risk can be greater than the risk associated with an individual test. This does not mean that any particular secondary finding is false; it means that unadjusted secondary results should be interpreted cautiously, especially when they are not supported by a prespecified testing strategy.

The posted primary outcome has 27 participants in each arm. The three posted secondary pain-at-rest outcomes have 26 participants in the experimental arm and 25 in control. The registry does not report the reasons for these differences, the amount or pattern of missing data, whether any imputation was used, or whether analyses followed an intention-to-treat or other population definition. The analysis population is not reported in the registry record.

The record also does not report a formal statistical analysis plan, original sample-size justification, interim analyses, or prespecified handling of multiple comparisons. These absences do not demonstrate that such procedures were not used; they mean that they cannot be evaluated from this registry entry. The planning illustrations based on observed effects do not fill that gap because they are not the trial’s own design assumptions.

16. 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 5% reporting threshold.

Most frequent non-serious adverse event terms

For serious adverse events, the registry lists zero affected participants in each arm. The experimental group had 26 participants at risk for serious events, and the control group had 25 at risk. The record also lists zero deaths in both groups. These are the counts posted in the registry; they do not establish that no unrecorded or unreported events occurred.

The registry lists other, non-serious adverse events for 18 participants in the experimental arm and 17 in the control arm, with 27 participants at risk in each group. No serious adverse event terms are listed. The record does not provide further detail about the nature, timing, severity, or relatedness of the other events, so those counts should not be interpreted as a complete description of event profiles.

General statistical context: when event counts are small or absent, the observed counts alone give limited information about the range of event rates that might occur in a larger group. The listed denominators also differ for serious-event reporting between arms. The registry record does not explain that difference or provide additional safety analyses. These figures describe the posted safety data and do not establish comparative safety.

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

The primary result is an estimated mean pain score of 5.4 in the liposomal bupivacaine arm and 5.8 in the placebo arm at nerve block resolution. The recalculated difference is -0.4, with an interval from -1.955 to 1.155. The estimate points toward a lower observed mean in the experimental arm, but the interval includes zero and values on either side. The registry’s own two-sided test reports p = 0.66. Taken together, the primary data do not provide a precise estimate of the direction or size of the difference.

This does not establish that the groups are equivalent. Equivalence requires a prespecified margin defining differences small enough to count as practically similar, and no such margin is reported. Nor does a non-significant test show that the treatment has no effect. It indicates that the posted primary data do not strongly distinguish the observed comparison from the no-difference model under the reported test.

The findings also do not establish the importance of a difference to patients. The registry defines the scale endpoints but does not state a threshold for a meaningful change. The primary outcome is one assessment at block resolution, not a summary of all pain experiences during recovery. The secondary findings offer additional observations at rest on postoperative days, but the record does not report results for pain with motion or oral analgesic requirements.

General statistical context: a trial result is an estimate from a particular sample and setting. Its uncertainty and the completeness of reporting affect how broadly it can be interpreted. The registry record does not provide enough information to assess the original sample-size rationale, missing-data handling, analysis population, or multiplicity procedures. The results should therefore be understood as the posted comparisons from this trial, rather than as definitive evidence for a broader population or as a statement about individual outcomes.

18. Why This Trial Matters Statistically

This trial illustrates why a point estimate and a test result are not enough to describe a continuous outcome comparison. The estimated primary difference is -0.4, but its interval extends from -1.955 to 1.155. The estimate alone points in one direction; the interval makes clear that substantial uncertainty remains about direction and size. Reporting both group summaries and an interval supports a more informative reading than relying on a p-value alone.

It also illustrates the distinction between failure to find strong evidence of a difference and evidence of equivalence. The primary p-value is not a measure of treatment effect, and the record reports no equivalence margin. Without a defined margin, the result cannot be converted into an equivalence conclusion. This distinction is important whenever a study’s interpretation might otherwise rest on a non-significant test.

The posted secondary outcomes highlight another statistical issue: multiple comparisons. Several outcomes and time points are listed, but a multiplicity strategy is not reported. Secondary results can be useful for describing patterns and generating questions, yet their evidential weight depends on how they were selected and analyzed. The record does not provide enough detail to assess that process.

Finally, the planning illustrations show how sample-size requirements depend on the effect a future study aims to detect. Smaller effects require larger planned samples under the stated assumptions. Because these illustrations use observed effects rather than the trial’s own documented design assumptions, they are useful as planning scenarios, not as evidence about the completed trial’s design or achieved power.

19. 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 comparison is based on 27 participants per arm, and its interval spans zero. This limits precision about the size and direction of the difference. The registry does not report a clinically important difference threshold, so the statistical interval cannot be judged against a stated patient-relevance criterion.

The registry lists seven secondary outcomes but posts results for only three pain-at-rest outcomes. Results for pain with motion and oral analgesic requirements are not reported in the registry record. This incomplete outcome set limits assessment of the broader postoperative pain and analgesic picture. The record also does not explain why the secondary outcome counts are 26 in the experimental arm and 25 in control, compared with 27 per arm for the primary endpoint.

Information needed to assess analysis choices is limited. The registry does not report the original sample-size justification, full statistical analysis plan, analysis population, missing-data methods, interim analyses, or multiplicity procedures. It identifies a two-sided t-test for the primary and posted secondary analyses but does not give further detail about model checks, covariate adjustment, or sensitivity analyses.

The outcome is a patient-reported score at nerve block resolution, reported during a follow-up phone call described as occurring at 24 hours. The record does not provide further detail about the timing variation in block resolution, the handling of any unavailable reports, or a threshold for a meaningful score difference. These limitations are specific to what is documented in this registry entry and do not establish what procedures may have been used outside the reported record.

20. Related Tutorials

21. Related Statistical Calculators

22. Sources

• ClinicalTrials.gov: Liposomal Bupivacaine After Arthroscopic Rotator Cuff Repair — NCT03149887.
• Registry record last updated 2020-01-23; status last verified 2020-01.
• Results first posted 2020-01-23.
• 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.

23. Record Summary

The registry record describes a completed Phase 4 randomized, quadruple-masked, parallel-group trial with 54 enrolled participants. It compares liposomal bupivacaine injected into the surgical field at the end of arthroscopic rotator cuff repair with placebo injection.

The primary endpoint is mean numeric rating pain score at nerve block resolution. The observed means were 5.4 in the experimental arm and 5.8 in control, with a recalculated unadjusted difference of -0.4 and interval from -1.955 to 1.155. The sponsor reports a two-sided p-value of 0.66.

Three secondary pain-at-rest outcomes have posted results; the other listed secondary outcomes do not. The record does not report the trial’s original sample-size justification, multiplicity approach, or missing-data methods.