Music Therapy Versus Control for Total Knee Arthroplasty: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Music Therapy Versus Control for Total Knee Arthroplasty (NCT03569397), a randomized na study. The primary outcome is Patient Satisfaction.

2. Clinical Question

The study’s background gives a rationale for examining music during surgery: it describes prior work involving different kinds of surgery and identifies total knee arthroplasty as a setting for further study. Those background statements are not trial results. The record describes a randomized, parallel-group comparison, but it does not report outcome values, an estimated treatment contrast, or an inferential analysis. Consequently, the registered question about satisfaction cannot be answered comparatively from the posted results.

3. Trial Design

The record describes a randomized, single-masked, parallel-group trial of music therapy versus no music therapy during total knee replacement under spinal anesthesia. The intervention group received music therapy during the operation. The comparator group had no headphones or music therapy. The study is listed as completed, with enrollment of 57 participants. The record lists University of Alabama at Birmingham as the sponsor.

The listed start date is 2018-10-08, and the primary completion date is 2019-12-18. These dates describe the record’s study timeline; they do not indicate when results were analyzed or posted. The phase is listed as NA. The registry record does not identify who was masked, explain how masking was maintained, or describe whether masking was assessed. “Single” masking alone does not establish which people involved in the trial were unaware of assignment.

The record lists one primary outcome measure: patient satisfaction, assessed on postoperative day 1. Participants in the music therapy group were asked to rank their satisfaction with perioperative care on a Likert scale from 1 to 5, where 1 indicates poor satisfaction and 5 indicates excellent satisfaction. Only participants assigned to music therapy were asked for this rating. The record lists no analyses and gives no primary outcome results. It therefore documents the intended randomized comparison, but not an analyzed comparison of satisfaction between arms.

Allocation details beyond the randomized designation are not reported in the registry record. In particular, the randomization sequence method, concealment procedures, eligibility criteria, and planned allocation ratio are not reported. The group counts in the safety listing are 29 and 28, but these counts do not establish the intended allocation procedure.

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 Patient Satisfaction, measured over Postoperative day 1.

The primary endpoint is patient satisfaction with perioperative care, recorded on postoperative day 1. The record describes a Likert scale from 1 to 5: 1 indicates poor satisfaction and 5 indicates excellent satisfaction. It identifies the outcome as a continuous measure summarized by a mean and standard deviation. A mean describes the average score in a group, while a standard deviation describes how dispersed individual scores are around that average. These summaries can help characterize both the typical reported satisfaction and the variation among respondents.

Satisfaction is a patient-reported experience measure. It can represent how participants appraise their care, which is a different kind of outcome from a physiological measure or a clinical event. That makes the measure relevant to the study’s stated interest in patient experience. But an endpoint’s relevance does not establish that the intervention changes it.

A central limitation is built into the registry description: only participants in the music therapy group were asked to rate satisfaction. Without satisfaction ratings in the non-music therapy group, the outcome cannot provide a direct randomized comparison of mean satisfaction. The registry record reports no satisfaction values, standard deviations, or analysis. Thus, neither the level of reported satisfaction in the intervention group nor a difference between groups is available in the posted results. The record also does not report details such as the exact question wording beyond the stated scale description, how nonresponse was handled, or whether the outcome was collected for all assigned participants.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

Randomization assigns participants to study groups by a chance-based procedure. In general, this is intended to make groups comparable with respect to both measured and unmeasured characteristics, on average, so that outcomes can be compared with less risk of systematic assignment bias. The record labels this study randomized, but does not report the sequence-generation method, allocation concealment, or other implementation details. Those details matter for assessing how randomization was carried out and cannot be inferred from the designation alone.

What does a parallel-group design mean?

In a parallel-group trial, participants are assigned to one group and receive that group’s assigned approach. The record describes a music therapy group and a non-music therapy group. It does not describe participants crossing between approaches. The reported group counts in the adverse-event listing are 29 for music therapy and 28 for non-music therapy. These are the safety listing counts; the registry record does not describe whether all enrolled participants were included in every outcome analysis.

How should the primary outcome be summarized?

The endpoint is a score on a 1-to-5 satisfaction scale, and the record specifies a mean and standard deviation. In general, the mean is the arithmetic average of observed scores. The standard deviation describes how much scores vary around that average. Reporting both can characterize the center and spread of a continuous outcome, but neither statistic alone estimates a treatment effect. A comparison ordinarily requires a contrast between groups, with an uncertainty measure such as a confidence interval. The registry record reports no group means, standard deviations, contrast, or confidence interval for satisfaction.

A confidence interval is, in general, a range of values compatible with the data and the statistical model under the method used. Its width reflects precision: a narrower interval indicates greater precision than a wider one, under the same approach. A confidence interval does not guarantee that the true effect lies inside it, and it does not replace attention to the endpoint, design, missingness, or analysis assumptions. No confidence interval for the primary outcome is reported in this registry record.

Can the satisfaction endpoint support a randomized comparison?

A between-group effect requires outcome information from both randomized groups. Here, the endpoint description says that only participants in the music therapy group were asked for satisfaction ratings. Without comparable ratings in the non-music therapy group, a group contrast cannot be estimated from the described endpoint. This is not merely a question of choosing a statistical test: the comparator outcome itself is not described as collected. The record provides no separate analysis that resolves this limitation.

What does the stated planning approach describe?

The record’s sample-size assumptions describe a planning illustration based on a stated fraction of an observed effect, a two-sided significance level of 0.05, equal allocation, and a normal approximation. In general, a planning calculation asks how many participants per arm might be needed to detect an assumed effect under specified statistical assumptions. Such a calculation is conditional on its assumptions and does not show the probability that this completed trial detected an effect. It is not observed power. The registry record does not report a trial-specific sample-size justification, the assumed effect used in the original design, or whether the stated illustrative assumptions were part of the protocol.

A normal approximation uses a reference distribution based on the normal distribution to estimate uncertainty or plan a test. Whether such an approximation is suitable depends on the outcome, its distribution, sample size, and analysis. The record does not report the details needed to assess its use for the trial’s actual data. Also, because no primary outcome results are posted, the observed effect referenced by the planning illustration cannot be evaluated from this record.

What can a p-value tell a reader?

In general, a p-value measures how incompatible the observed data are with a specified null hypothesis, under the assumptions of the statistical model. It is not the probability that the null hypothesis is true, nor does it measure the size or importance of an effect. Interpretation should be paired with the estimated effect and its precision. No primary outcome p-value or test is reported in the registry record, so there is no inferential result to interpret.

Statistical methods for the primary endpoint—including the exact comparison, model, handling of the bounded scale, covariate adjustment, and confidence-interval method—are not reported in the registry record. The record also does not report an analysis population or a missing-data method. Without those details and without outcome results, statistical conclusions about comparative satisfaction are unavailable.

10. Confidence Intervals for Each Arm

No two-arm comparison is shown for this trial, but each arm's mean can be given with a t-based 95% confidence interval computed from the posted mean, spread and number of participants.

R code and output

arm <- c("Music Therapy")
n   <- c(29)
m   <- c(4.48)
sp  <- c(0.16)
sd  <- sp      # posted standard deviations
for (i in seq_along(n)) {
  se <- sd[i] / sqrt(n[i]); h <- qt(0.975, n[i] - 1) * se
  cat(sprintf("CARM|%s|%d|%.3f|%.3f|%.3f|%.3f\n", arm[i], n[i], m[i], sd[i], m[i] - h, m[i] + h))
}

CARM  Music Therapy  29  4.480  0.160  4.419  4.541

11. Multiplicity, Missing Data and Analysis Populations

The registry record lists one primary outcome measure, patient satisfaction, and lists no analyses. A single listed endpoint does not by itself reveal whether additional outcomes or comparisons were planned, whether any interim analyses were conducted, or how the analysis plan handled multiple testing. A multiplicity strategy is not reported in the registry record. No interim analysis information is reported either.

The primary endpoint description states that only participants in the music therapy group were asked for satisfaction ratings. Thus, the issue is not only whether any ratings are missing: a satisfaction measure for the comparator group is not described as collected. The record does not report the number of participants who completed the satisfaction measure, the number of missing responses, reasons for missingness, or methods for handling missing data.

The analysis population is also not reported. The registry record does not say whether the planned analysis would include all randomized participants, only those who received the assigned intervention, or another defined group. It does not describe adherence, exclusions after randomization, or how participants with unavailable outcome data would be treated analytically. These omissions prevent assessment of whether an analysis would preserve the benefits of randomization or how sensitive the result might be to missing observations.

Because no primary outcome results or analyses are posted, there is no basis for evaluating the impact of multiplicity or missing data on an estimated treatment effect. The absence of these details should be distinguished from evidence that a particular method was or was not used.

12. 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 0% reporting threshold.

The registry lists 29 participants at risk in the music therapy group and 28 in the non-music therapy group. For each group, the posted serious-event count is 0, the other-event count is 0, and the death count is 0. These are the adverse-event figures recorded for the listed groups.

Such counts describe what the registry reports, not the full context of safety monitoring. The record does not provide definitions for serious or other events, a list of event types, event collection methods, or details about duration of follow-up. It also does not state whether the at-risk counts correspond to every participant enrolled or to a particular safety population. The posted zeros should therefore be interpreted as zero reported events in these registry fields, rather than as proof that events were impossible or that all possible events were captured.

The safety listing is distinct from the primary satisfaction endpoint. The registry record does not report a statistical comparison of adverse events between groups. With no event counts beyond zeros in the listed fields and no further detail, the record supports only a descriptive reading of the reported figures, not a broader comparative safety conclusion.

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

The record documents a randomized trial of music therapy during total knee replacement under spinal anesthesia, with a no-music comparator and a stated primary outcome of patient satisfaction on postoperative day 1. It reports enrollment of 57 and describes the satisfaction scale. These details establish the trial’s question and the way the primary endpoint was defined.

They do not establish the answer to that question. The registry record does not report satisfaction scores, variability, a between-group estimate, a confidence interval, or a p-value. Moreover, only the music therapy group was asked to provide satisfaction ratings. Without a corresponding comparator outcome, the registered endpoint cannot yield the direct randomized comparison implied by the study question. No conclusion about whether satisfaction differed between groups is supported by the posted results.

The record’s completed status does not fill this gap. Trial completion and the availability of analyzable, reported outcomes are separate matters. The listed adverse-event fields show zero serious events, zero other events, and zero deaths in each group’s safety listing, but the record does not describe event definitions or ascertainment in enough detail to broaden that observation.

General statistical principles can clarify what would be needed for a comparative result: outcome measurements in both groups, an analysis plan, an effect estimate, and an account of uncertainty and missing data. Those elements are not reported for the primary endpoint in this record. The right interpretation is therefore not that music therapy did or did not change satisfaction, but that the registry information does not permit that effect to be estimated.

14. Why This Trial Matters Statistically

This trial is statistically notable because the randomized design and the primary outcome description do not align to produce a reported between-group endpoint comparison. Randomization creates a framework for comparing assigned groups, but a comparative endpoint requires that the outcome be measured in both groups. The registry record says satisfaction was asked only of participants assigned to music therapy. That limits what can be learned from the stated primary outcome independently of which statistical test might otherwise have been selected.

The distinction between a study question and an estimable quantity is important. A trial may ask whether an intervention changes an experience, while its outcome collection may describe only one arm. In that circumstance, a mean in the intervention group—if reported—would describe that group’s ratings but would not show how those ratings compare with the control group. A treatment effect requires a contrast, and the registry record does not report the outcome data needed for one.

The record also illustrates why a completed trial label should not be confused with a complete statistical account. Results, analysis populations, missing-data procedures, and inferential methods are not reported. The stated planning illustration is not an observed-power result and cannot replace an outcome analysis. For readers assessing evidence, these distinctions help prevent design labels, sample counts, or planning assumptions from being mistaken for findings.

The trial addresses a specific surgical setting identified in its title and background. Its registry record can inform readers about the intended comparison and endpoint, while leaving the comparative satisfaction result unknown. That boundary is itself a meaningful statistical conclusion about the available record.

15. 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 principal limitation for interpreting this specific trial record is that the primary endpoint is not reported as measured in both arms. The registry description says only the music therapy group was asked to rate satisfaction. As a result, the stated endpoint does not support a direct comparison with the non-music therapy group, even if intervention-group scores had been reported. No scores are reported in any case.

The registry record lists no analyses and does not provide an effect estimate, uncertainty interval, or test result. Statistical methods for the satisfaction endpoint, including any adjustment or model, are not reported. Details of randomization implementation and the identity of the masked party are also not reported. The designation of a randomized, single-masked trial does not supply those missing procedural details.

Information about missing outcomes, analysis populations, adherence, exclusions, and the handling of participants without outcome data is not reported in the registry record. The scale is described as a 1-to-5 satisfaction rating, but the record does not give further information about response collection or the number of ratings obtained. The safety listing gives event counts but does not explain event definitions or ascertainment.

Finally, the stated planning illustration should not be read as the original design justification or as evidence of achieved power. The registry record does not report the trial’s own sample-size justification or an observed primary-outcome effect. These gaps constrain interpretation of the trial record; they do not establish that a particular unreported procedure or result occurred.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Music Therapy Versus Control for Total Knee Arthroplasty — NCT03569397.
• Registry record last updated 2021-05-05; status last verified 2020-11.
• Results first posted 2021-05-05.
• 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.

19. Record Summary

The registry record describes a completed, randomized, single-masked, parallel-group trial sponsored by University of Alabama at Birmingham. It enrolled 57 participants and compared music therapy during total knee replacement under spinal anesthesia with no headphones or music therapy. The listed start date is 2018-10-08, and the primary completion date is 2019-12-18.

The primary outcome was patient satisfaction on postoperative day 1, rated on a scale from 1 to 5. Only participants in the music therapy group were asked to provide this rating. The registry record lists no analyses and reports no satisfaction results or between-group estimate. The adverse-event listing reports zero serious events, zero other events, and zero deaths in each group. The record does not report the analysis plan, missing-data approach, or analysis populations.