Liposomal Bupivacaine Versus Standard of Care in Total Knee Surgery: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Liposomal Bupivacaine Versus Standard of Care in Total Knee Surgery (NCT02219087), a randomized na study. The primary outcome is Number Physical Therapy Sessions Necessary for Discharge.

2. Clinical Question

3. Trial Design

The registry describes a completed, randomized, single-masked, parallel-group trial sponsored by OhioHealth. It lists an enrollment of 60 and a phase of NA. The study concerned analgesia following total knee arthroplasty in people with knee osteoarthritis. The registry records the study start as 2014-08 and primary completion as 2016-03.

The treatment contrast was between a local liposomal bupivacaine approach and standard-of-care analgesia. The arm descriptions indicate that both groups received a pre-operative adductor canal nerve block with ropivacaine. The liposomal bupivacaine group received the study drug distributed into specified tissue areas. The comparator group instead had a surgeon-administered intra-operative popliteal nerve block and a peri-articular injection of morphine, ketorolac, and methylprednisolone. Thus, the comparison is between the described analgesic approaches, not between liposomal bupivacaine and no analgesia.

The primary outcome was the number of physical therapy sessions needed for discharge during the hospital stay. The posted outcome summaries list 30 participants in the liposomal bupivacaine group and 29 in the standard-of-care group. Why these outcome counts differ from the enrollment figure is not reported in the registry record. Details about eligibility criteria, the identity of the masked party, allocation concealment, and the trial's original statistical design assumptions are not reported in the registry record. The registry includes a sponsor-reported two-sided t-test for the primary outcome and selected secondary outcomes; other analysis details are limited.

4. Participant Flow and Accounting

The registry reports how participants moved through each stage of the study. All counts below are exactly as posted; missing counts are not inferred from other stages.

Overall Study

Reasons for not completing this period:

5. Baseline Characteristics

The table reproduces the baseline characteristics posted in the registry, which describe the participants analysed at baseline and help show whether the randomized groups were comparable.

6. Primary Endpoint

The registry lists the primary outcome as Number Physical Therapy Sessions Necessary for Discharge, measured over Participants will be followed for the duration of their hospital stay, an expected average of 2.5 days..

The primary endpoint counts the physical therapy sessions a participant needed before discharge. It is therefore a measure of rehabilitation activity during the surgical admission, rather than a direct measure of pain intensity or a longer-term recovery outcome. The registry says participants were followed for the duration of their hospital stay, with an expected average of 2.5 days.

The record describes a decrease of at least 2 sessions as significant and notes that there are typically 2 sessions per day, with each patient completing an average of 4-5 sessions during admission. These details give context for the endpoint's intended scale and clinical interpretation. They do not establish that a difference smaller than 2 sessions is unimportant, nor do they explain whether the threshold was prespecified in the trial's analysis plan; that plan is not reported in the registry record.

A count of sessions is summarized in the posted results using a mean and standard deviation. The mean describes the average number of sessions in each group, while the standard deviation describes how dispersed individual values were around that average. The reported group means were 3.0 sessions for liposomal bupivacaine and 3.6 for standard of care. The registry does not report individual participant values or the distribution of session counts, so the group summaries do not show how much the participants' experiences varied beyond the stated standard deviations.

7. Results Posted in the Registry

• Liposomal Bupivacaine: mean 3.00 versus 3.60 on control; difference -0.60 (95% CI -1.24 to 0.04), standardized effect d = -0.48; z-test p = 0.066.

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 Visual Analog Scale (VAS) Pain Scores During Hospital Stay

• 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:
  • Liposomal Bupivacaine: mean 4.40 versus 4.70 on control; difference -0.30 (95% CI -1.02 to 0.42), standardized effect d = -0.21; z-test p = 0.412.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between Liposomal Bupivacaine and the control. The interval gives the range of effects that remain compatible with the data.

Length of Stay (LOS, in Days)

• 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:
  • Liposomal Bupivacaine: mean 2.50 versus 2.30 on control; difference 0.20 (95% CI -0.14 to 0.54), standardized effect d = 0.30; z-test p = 0.248.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between Liposomal Bupivacaine and the control. The interval gives the range of effects that remain compatible with the data.

Opioid Consumption in Oral Morphine Equivalents (OMEs, in Milligrams)

• 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:
  • Liposomal Bupivacaine: mean 274.60 versus 304.80 on control; difference -30.20 (95% CI -98.01 to 37.61), standardized effect d = -0.23; z-test p = 0.383.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between Liposomal Bupivacaine and the control. The interval gives the range of effects that remain compatible with the data.

The secondary outcomes with numerical results cover pain during the hospital stay, length of stay, and opioid consumption. Their recalculated mean differences are modest in relation to the uncertainty represented by their intervals, and each interval includes zero. The registry also lists opioid-related adverse events, total cost of care, and hospital readmission as secondary outcomes, but numerical results for these outcomes are not reported in the registry record. The posted results therefore do not support a full assessment across all listed secondary measures.

This overall pattern is consistent with the primary result in one important statistical respect: the available estimates do not sharply resolve whether the groups differed. It does not establish that all outcomes were equal, and secondary measures do not independently settle the primary question about physical therapy sessions. Pain, length of stay, opioid consumption, and discharge-related therapy counts also represent different aspects of care, so one outcome cannot stand in for another.

In general, interpreting several outcomes raises a multiplicity concern. When many comparisons are made, the chance of at least one apparently unusual result can increase, even if there are no true differences. The registry does not report a multiplicity adjustment, a hierarchy that identifies confirmatory outcomes, or a complete analysis plan for secondary outcomes. The individual unadjusted secondary results consequently carry less confirmatory weight than a prespecified primary analysis would, and any isolated finding would need cautious interpretation. No such finding should be selected as decisive without accounting for the set of outcomes and the missing results.

The secondary outcomes can still add context by showing what was measured and by indicating whether the posted directions are broadly consistent or varied. They are most useful as descriptive evidence alongside the primary comparison, rather than as multiple independent tests that can establish efficacy. The registry record does not report enough detail to determine how these outcomes were prioritized or whether they informed a prespecified broader conclusion.

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

• Mean Visual Analog Scale (VAS) Pain Scores During Hospital Stay
• Length of Stay (LOS, in Days)
• Opioid Consumption in Oral Morphine Equivalents (OMEs, in Milligrams)
• Number of Participants With Opioid-related Adverse Events (ORAEs) During Hospital Stay
• Total Cost of Care (Dollars)
• Hospital Readmission Not Including Admissions Planned Procedures

9. Statistical Interpretation

10. Statistical Methods Explained

The primary outcome is continuous in the registry's statistical classification and is reported as a mean with a standard deviation. A mean is the arithmetic average of the observed values in a group. A standard deviation describes how spread out those values are around the mean; it is not the uncertainty in the estimated mean itself. The posted primary summaries are 3.0 sessions with a standard deviation of 1.2 for liposomal bupivacaine, and 3.6 sessions with a standard deviation of 1.3 for standard of care.

The recalculated comparison is an unadjusted mean difference. It subtracts the standard-of-care mean from the liposomal bupivacaine mean, giving -0.6 sessions. The sign depends on that ordering: a negative result means the posted mean was lower in the liposomal bupivacaine group. The standardized effect size is -0.48. In general, a standardized effect expresses a mean difference relative to the variability of the outcome, which can help describe magnitude on a scale that is not tied to the original measurement units. It does not replace the result in sessions or establish clinical importance.

The recalculated test uses posted group summaries and is an unadjusted comparison. In general, a two-sided test evaluates departures in either direction rather than testing only whether one named group has a lower result. The registry reports the sponsor's primary analysis as a two-sided t-test with p = 0.137. The recalculated unadjusted p-value is 0.066. A p-value describes how unusual data at least as incompatible with a specified no-difference model would be under that model and the test assumptions. It is not the probability that the null hypothesis is true, nor does it measure the size or importance of a difference. The registry does not report the sponsor's full analysis details, so the difference between the two p-values cannot be explained from the record.

The recalculated primary interval is -1.239 to 0.039 sessions. In general, a confidence interval is a range produced by a method intended to express uncertainty around an estimate. Its interpretation depends on the confidence level and analysis procedure. The confidence level for the posted recalculated intervals is not reported in the registry record, so it should not be assigned a conventional percentage. Because this interval includes zero, the summaries are compatible with no mean difference under the interval procedure, as well as with differences in either direction.

The secondary continuous outcomes use the same general approach: group means and standard deviations, followed by unadjusted mean-difference recalculations. The pain-score means were 4.4 and 4.7 units, with a recalculated difference of -0.3 and p = 0.412. For length of stay, the means were 2.5 and 2.3 days, with a recalculated difference of 0.2 and p = 0.248. For opioid consumption, the means were 274.6 and 304.8 milligrams, with a recalculated difference of -30.2 and p = 0.383. In each comparison, the direction is liposomal bupivacaine relative to standard of care. The corresponding sponsor-reported p-values are 0.343, 0.208, and 0.385, respectively.

In general, variability matters because estimates based on more dispersed values tend to be less precise when other features are similar. Over-dispersion is a particular concern for count outcomes when observed variation exceeds what a simple count model expects; it can make standard errors too small if the analysis does not account for that extra variation. The registry reports the primary outcome as a mean and standard deviation and a sponsor t-test, but does not report distributional checks, a count model, or any assessment of over-dispersion. The available information therefore does not establish which alternative modeling choices were considered.

The planning illustrations use the observed effect as a starting point, then consider detecting a stated fraction of that effect. Their assumptions are a two-sided significance level of 0.05, equal allocation between the two arms, and a normal approximation. For continuous outcomes, the figures are participants per arm. Such calculations describe hypothetical future study sizes under those assumptions; they are not estimates of the trial's achieved statistical power. Smaller target effects generally require more participants to distinguish them from random variation with the same planned power.

The registry does not report whether the trial's original analysis adjusted for baseline characteristics, how missing outcome values were handled, which analysis population was used, or whether any interim analyses were conducted. Those details affect how an analysis should be interpreted and cannot be reconstructed from group means and standard deviations alone.

11. Confidence Intervals and Precision

The primary recalculated mean difference is -0.6 sessions, and its interval extends from -1.239 to 0.039. The negative point estimate favors a lower mean number of sessions in the liposomal bupivacaine group, but the interval reaches slightly above zero. It therefore does not exclude no difference or a small difference in the opposite direction. The interval also does not establish that the true difference is within the registry's stated threshold of at least 2 sessions.

The interval's width reflects uncertainty in the estimated group difference. In general, a narrower interval indicates greater precision, while a wider interval leaves a broader range of values compatible with the data and method. The registry does not report the confidence level for the recalculated interval. It would therefore be inappropriate to label it with a confidence percentage not present in the record. The standard deviations of 1.2 and 1.3 sessions describe observed group variation, while the interval describes uncertainty in the estimated difference; these are related but distinct quantities.

For the secondary outcomes, the recalculated intervals are -1.017 to 0.417 units for pain scores, -0.139 to 0.539 days for length of stay, and -98.01 to 37.61 milligrams for opioid consumption. Each includes zero. Their widths and units differ, so the numerical widths cannot be compared directly as measures of importance. The reported group summaries and intervals do not provide the individual-level distributions or establish how robust the results are to alternative assumptions.

Precision is not the same as clinical importance. The primary estimate is expressed in sessions and can be considered alongside the registry's stated decrease threshold, but the interval remains too broad to settle the size or direction of the underlying difference. A result with uncertainty spanning no difference should not be read as proof that the groups are equivalent; equivalence would require an appropriate design and prespecified margin, neither of which is reported in the registry record.

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 figures are hypothetical sample-size illustrations based on the observed effect, not the trial's original design calculations. For continuous outcomes, they are participants per arm, not a total across both arms and not total events. The stated assumptions are a two-sided significance level of 0.05, equal allocation between the two arms, a normal approximation, and a target effect equal to the listed fraction of the observed effect. The original trial's own sample-size justification is not reported in the registry record.

For the primary outcome, planning for 100% of the observed effect gives 69 participants per arm for 80% power and 92 participants per arm for 90% power. Planning for 75% of the observed effect gives 122 participants per arm for 80% power and 163 participants per arm for 90% power. Planning for 50% of the observed effect gives 273 participants per arm for 80% power and 365 participants per arm for 90% power.

In general, power is the chance that a planned study will meet its specified statistical decision rule if the target effect is truly present and the planning assumptions hold. The 80% and 90% columns describe different planned chances of detecting the target effect under those assumptions; higher planned power generally requires a larger sample. A smaller effect is harder to distinguish from random variation, so the illustrations require more participants as the target fraction of the observed effect becomes smaller. These planning figures are not observed power: they do not tell whether the completed trial had a particular probability of detecting its actual effect.

The illustrations depend on assumptions that may not match a future study or the trial's actual design. In particular, they use a normal approximation and equal allocation. They should be read as planning scenarios, not as evidence that the original enrollment was adequate or inadequate. The registry record does not report the original sample-size rationale.

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 = -0.600; pooled standard deviation σ = 1.250.
2. n = 2 × (1.96 + 0.842)² × 1.250² / -0.600² = 68.1, rounded up to 69 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 <- -0.6                      # observed difference in means
sigma <- 1.25012280098551                     # 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(2219087)
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 = 69 (80% power), 92 (90% power)
 75% of observed effect: n per arm = 122 (80% power), 163 (90% power)
 50% of observed effect: n per arm = 273 (80% power), 365 (90% power)
power.t.test: 69.1 
Simulated power at n = 69 per arm: 0.799 (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

For the primary outcome, the registry reports a sponsor analysis using a two-sided t-test, with p = 0.137. The simple unadjusted recalculation from the posted group summaries gives a mean difference of -0.6 sessions and p = 0.066. These values should be kept distinct: one is the reported sponsor test, and the other is a recalculation from the group means, standard deviations, and group sizes.

The registry does not report an estimate or interval alongside the sponsor's primary p-value, and it does not provide enough analysis detail to explain why the p-values differ. The record does not flag a discrepancy, so the recalculation is not identified as conflicting with a posted result. The sponsor's test is the trial's reported analysis; the recalculated estimate and interval provide a separate, transparent summary based on the posted statistics.

The same distinction applies to the secondary outcomes with numerical summaries. Sponsor-reported p-values are 0.343 for pain scores, 0.208 for length of stay, and 0.385 for opioid consumption. Their corresponding simple recalculated p-values are 0.412, 0.248, and 0.383. The registry does not report the full sponsor analysis outputs or methods needed to reconcile these differences. Neither set of p-values should be interpreted without considering the estimates, uncertainty, outcome context, and limitations in the registry record.

15. Multiplicity, Missing Data and Analysis Populations

The registry identifies a primary outcome and several secondary outcomes, but the analysis plan is not reported in sufficient detail to determine how the full set of comparisons was handled. The sponsor analyses listed for the primary and three secondary continuous outcomes use two-sided t-tests. Whether those tests were prespecified, whether other models were considered, and whether any multiplicity adjustment was applied are not reported in the registry record.

Multiplicity matters because evaluating many outcomes can make a chance finding more likely. A prespecified primary outcome can help focus interpretation, but it does not by itself resolve the interpretation of multiple secondary tests. The registry does not describe a testing hierarchy, family-wise error control, or another method for accounting for multiple comparisons. The secondary p-values should therefore be regarded as unadjusted evidence unless the record reports otherwise; no adjustment should be assumed.

Missing-data handling is also not reported in the registry record. There is no description of how participants without an endpoint measurement were treated, whether imputation was used, or whether completeness differed by group. The primary summaries list 30 participants in one arm and 29 in the other, while enrollment is recorded as 60; the reason for the difference is not reported. The data do not establish whether it reflects missing outcomes, exclusions, or another cause.

The analysis population is not reported in the registry record. It is therefore unclear whether the posted analyses included all randomized participants, only participants with observed outcomes, or another defined group. The registry also does not report details of randomization implementation, allocation concealment, baseline adjustment, protocol deviations, or interim analyses. These omissions limit assessment of potential bias and reproducibility. They do not show that any particular problem occurred; they mean that the record does not permit that question to be answered.

16. Safety Results

The registry reports serious adverse events as affected participants divided by participants at risk.

Other (non-serious) adverse events

Participants with at least one non-serious event at or above the registry's 0% reporting threshold.

Most frequent non-serious adverse event terms

The registry lists zero serious adverse events among 30 participants at risk in the liposomal bupivacaine group and zero among 29 participants at risk in the standard-of-care group. No serious adverse event terms are listed. These figures describe the serious-event counts recorded for the groups; they do not establish that the risk of serious events is absent or that the groups have identical safety profiles.

Other adverse events are listed for 13 participants in the liposomal bupivacaine group and 11 in the standard-of-care group. The record does not provide event descriptions or severity details for these other events in the information available for this analysis. It also does not report deaths in the adverse-event fields, so death counts should not be inferred from the serious-event figures. Definitions, collection procedures, and follow-up beyond the hospital stay are not reported in the registry record.

With limited group sizes and a hospital-stay observation period, counts alone give a narrow description of what was recorded in this trial. Zero observed serious events is not evidence that an event could never occur, while the other-event counts do not by themselves identify a causal relationship with either analgesic approach.

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

The primary posted group means were 3.0 physical therapy sessions with liposomal bupivacaine and 3.6 with standard of care. The recalculated mean difference of -0.6 sessions points toward fewer sessions in the liposomal bupivacaine group, but the interval from -1.239 to 0.039 includes zero. The sponsor-reported two-sided test has p = 0.137. Taken together, the record does not precisely establish the size or direction of a difference in this outcome.

This does not prove that the approaches are equivalent, nor does it prove that there is no effect. Equivalence or noninferiority requires a defined framework and an appropriate margin; neither is reported in the registry record. Likewise, the numerical direction of an estimate should not be turned into a claim that one approach works better. The posted results describe a comparison with uncertainty, not a definitive treatment conclusion.

The primary endpoint is a count of therapy sessions required for discharge during the hospital stay. It is not a direct measure of long-term function, persistent pain, or recovery after discharge. The secondary numerical outcomes likewise concern the hospital stay. Their estimates do not answer questions about outcomes beyond the recorded follow-up period, and the registry lists other secondary measures without numerical results in the record summarized.

Random allocation can support a fair comparison when implemented and analyzed appropriately, but the registry does not report enough detail to assess all aspects of conduct, missing data, or analysis. The posted summaries should therefore be interpreted within the limits of the recorded design and reporting. They can inform statistical understanding of the observed comparison, but should not be used alone to make individual treatment decisions.

18. Why This Trial Matters Statistically

This trial illustrates why a group difference should be read together with its uncertainty. The primary means differ numerically, but the recalculated interval includes zero and covers a range extending in both directions. A point estimate alone can give an overly definite impression; an interval shows that the data are compatible with more than one underlying comparison.

It also illustrates the distinction between a reported analysis and a simple recalculation. The registry's sponsor-reported primary p-value is 0.137, while the unadjusted recalculation from posted summaries gives 0.066. Without the complete analysis plan and sponsor estimates, these values cannot be reconciled. Reporting both transparently avoids treating the recalculation as a replacement for the trial's own test or mistaking a p-value for an effect size.

Planning illustrations provide a further statistical lesson. Required sample size depends on the effect a future study aims to detect, as well as its design assumptions and desired power. The illustrations increase as the target effect is made smaller. They do not establish whether the completed trial was adequately powered, because the original design rationale is not reported and the illustrations are not observed power.

Finally, the record highlights the importance of complete outcome and methods reporting. Multiple secondary outcomes are listed, but numerical results are not available for all of them, and multiplicity, missing-data handling, and analysis populations are not described. These details affect how confidently researchers can interpret the overall evidence and reproduce the analysis.

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 registry record gives limited information about eligibility, participant characteristics, and the implementation of masking and randomization. It does not identify who was masked, explain allocation concealment, or describe baseline balance. These omissions limit assessment of how the randomized comparison was conducted, without showing that a specific problem occurred.

The posted primary summaries list 30 participants in the liposomal bupivacaine group and 29 in the standard-of-care group, while the enrollment figure is 60. The reason for this difference is not reported in the registry record. Missing-data handling, exclusions, and the analysis population are also not reported, so the effect of any missing or excluded observations cannot be assessed.

The primary outcome is measured over the hospital stay, and the registry gives an expected average stay of 2.5 days. The record does not provide longer-term outcomes for pain, function, or recovery. The numerical secondary results available for analysis are limited to pain scores, length of stay, and opioid consumption; results for other listed secondary outcomes are not reported in the registry record.

The sponsor's reported primary test is accompanied by a p-value but not an estimate or interval in the registry record. The unadjusted recalculation gives a different p-value, and the record does not provide the analytic details needed to explain the difference. The confidence level for the recalculated intervals is not reported. Finally, the registry does not report the original sample-size rationale, multiplicity strategy, interim analyses, or distributional checks for the session count. These reporting limits make it difficult to assess robustness beyond the posted summaries.

20. Related Tutorials

21. Related Statistical Calculators

22. Sources

• ClinicalTrials.gov: Liposomal Bupivacaine Versus Standard of Care in Total Knee Surgery — NCT02219087.
• Registry record last updated 2018-01-02; status last verified 2017-12.
• Results first posted 2018-01-02.
• 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 describes a completed, randomized, single-masked, parallel-group trial sponsored by OhioHealth, comparing liposomal bupivacaine with standard-of-care analgesia in total knee arthroplasty. The primary outcome was the number of physical therapy sessions necessary for discharge during the hospital stay.

The posted primary means were 3.0 sessions for liposomal bupivacaine and 3.6 for standard of care. The unadjusted recalculation gives a mean difference of -0.6 sessions, an interval from -1.239 to 0.039, and p = 0.066. The sponsor-reported two-sided test has p = 0.137. The interval includes zero, and the registry record does not provide enough analysis detail to reconcile the two p-values.

Numerical results are also available for selected secondary outcomes, while results for other listed outcomes and several analysis details are not reported in the registry record. The findings are best read as estimates with uncertainty rather than as proof of benefit, no effect, or equivalence.