Virtual Reality Distraction During Outpatient Pediatric Orthopedic Procedures: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Virtual Reality Distraction During Outpatient Pediatric Orthopedic Procedures (NCT05510232), a randomized na study. The primary outcome is Absolute Difference in HR as Measured 3 Minutes Prior to Procedure and Maximum as Measured During Through 1 Minute After Procedure..

2. Clinical Question

3. Trial Design

The registry describes a completed, randomized, parallel-group study with no masking. It lists Hospital for Special Surgery, New York, as the sponsor. The recorded start date is 2018-07-25, and the primary completion date is 2022-05-19. The study status is completed, and its recorded phase is NA. These details establish the broad design and timeline; they do not describe the conduct of randomization or whether allocation was concealed.

Three groups are described. One watched a non-VR video on an iPad, one watched a non-VR video through a headset, and one was immersed in the Bear Blast VR game through a headset. The posted primary-outcome results list 74 participants for the iPad group, 73 for the headset video group, and 64 for the VR game group. The record does not explain how these outcome counts relate to the total enrollment of 226, or whether participants were excluded from the primary analysis.

The study description identifies cast removal and surgical suture or pin removal as outpatient procedures of interest. It describes heart-rate measurement using pulse oximetry, alongside patient-reported pain and anxiety and parent or guardian satisfaction as outcomes. The record names randomized allocation and a parallel model, but does not report further procedural details such as the randomization sequence, allocation concealment, or masking of those collecting or analyzing outcomes.

The intervention descriptions and arm labels are not entirely consistent in their wording. In particular, one adverse-event group is described as watching a VR video through a headset, while the intervention and arm descriptions characterize that group as watching a non-VR video. The registry does not clarify this wording difference. Results for the primary heart-rate outcome are reported for the three groups, but posted numerical results for the secondary outcomes are not reported in the registry record.

4. Participant Flow and Accounting

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

Before assignment: Some participants did not tolerate the distraction method (e.g. removed virtual reality headset) or removed the heart rate monitor.

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 Absolute Difference in HR as Measured 3 Minutes Prior to Procedure and Maximum as Measured During Through 1 Minute After Procedure., measured over 3 minutes pre-procedure until 1 minute post-procedure, up to 20 minutes.

The primary endpoint is titled as the absolute difference in heart rate measured three minutes before the procedure and the maximum heart rate measured during the procedure through one minute after it. The stated timeframe also says the measurement period may extend up to 20 minutes. Heart rate was measured by pulse oximetry. The registry expresses the outcome in beats per minute and reports the mean and standard deviation for each group.

The study description gives a rationale for recording heart rate: it identifies heart rate as an age-validated surrogate for pain and anxiety and as a way to quantify physiologic response. In general, a physiologic measure can complement a participant’s own report, but it does not directly record a person’s experience. It should therefore be interpreted as the specified heart-rate outcome, not as a direct measurement of pain or anxiety.

The word absolute in the endpoint title does not establish the direction of subtraction in the posted record. The results should consequently be read as group means for the titled difference measure, rather than assigning a positive value a more specific clinical meaning. The registry lists changes in Visual Analogue Scale pain and anxiety scores and a parent or guardian satisfaction questionnaire as secondary outcomes. Their numerical findings are not reported in the registry record.

7. Results Posted in the Registry

• A Treatment Group That Will Have Headset on and Will Watch a Non-VR Video: mean 20.00 versus 20.00 on control; difference 0.00 (95% CI -5.17 to 5.17), standardized effect d = 0.00; z-test p = 1.000.
• A Treatment Group That Will be Immersed in the VR Game (Bear Blast) Via the Headset.: mean 21.00 versus 20.00 on control; difference 1.00 (95% CI -4.35 to 6.35), standardized effect d = 0.06; z-test p = 0.714.

8. Statistical Interpretation

9. Statistical Methods Explained

The registry reports the primary outcome as a continuous measure summarized by means and standard deviations. A mean describes the arithmetic average in a group, while a standard deviation describes the spread of individual measurements around that average. These summaries make it possible to compare average outcomes, but they do not show the shape of the data, whether there were unusual observations, or how each participant changed.

What does the mean difference compare?

The posted mean differences compare each listed intervention group with the iPad video group. The headset video comparison is 0.0, and the VR game comparison is 1.0. The sign and magnitude summarize the contrast in group means using the record’s reported outcome scale. The record does not explain the subtraction convention for the endpoint’s absolute difference title, so interpretation should stay with the reported mean-difference estimates rather than attach an unreported direction to the within-person change.

In general, an unadjusted comparison uses the observed group summaries without adjustment for other covariates. The registry labels the p-values as unadjusted, but does not report whether any adjusted or model-based analyses were also conducted. It also records zero analyses. The exact analytic procedure used by the study team, including any assumptions or covariate handling, is not reported in the registry record. The comparison figures should therefore be read as the posted estimates and not as a complete account of the trial’s statistical analysis.

How should the p-values be read?

In general, a p-value measures how incompatible the observed data are with a specified statistical null model, assuming that model and its assumptions hold. It is not the probability that the null hypothesis is true, nor does it measure the size or practical importance of a difference. The unadjusted p-values of 1.0 and 0.714 accompany the two posted comparisons with the iPad group. Their meaning depends on the analysis and assumptions, which are not fully described in the registry. Neither value establishes equivalence or proves that the groups have identical outcomes.

Random allocation can support comparisons by reducing systematic differences between groups at assignment, on average. However, the registry record does not describe how randomization was generated, whether allocation was concealed, whether assignment was stratified, or how departures from the assigned intervention were handled. It also states that masking was none. The record does not say whether outcome measurement or analysis was performed by people unaware of group assignment.

What do the planning illustrations mean?

The record includes planning illustrations based on the observed VR-versus-iPad effect. They assume a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. The illustrations consider detecting 100%, 75%, or 50% of the observed effect. For planning at 100% of the observed effect, the estimates are 4,019 participants per arm for 80% power and 5,380 participants per arm for 90% power. At 75% of the observed effect, the corresponding figures are 7,145 and 9,565 participants per arm. At 50% of the observed effect, they are 16,075 and 21,520 participants per arm.

In general, power is the probability that a specified study design would reject a null hypothesis under a particular assumed effect and statistical model. These illustrations are not observed power for the completed trial, and they are not evidence that the original study was designed using those assumptions. They are planning scenarios calculated from the observed effect, as the registry explicitly notes. The record does not report the trial’s own sample-size justification or design assumptions. The planning estimates also pertain to a two-arm comparison, not to an analysis of all three groups together.

In general, smaller effects require more participants to distinguish them from random variation at a fixed significance level and power target. That relationship explains why the planning figures increase when the assumed fraction of the observed effect is smaller. It does not establish what effect size would be important to patients or clinicians. A target effect and the intended analysis would need to be justified independently; neither is reported in the registry record.

Over-dispersion is a general concern when data vary more than a statistical model expects. If that happens, standard errors and intervals based on a narrower variance assumption may be too small, producing overstated precision. Here, group standard deviations are reported, but the registry does not provide individual-level data, distributional diagnostics, or a description of a model that could be checked for over-dispersion. This is a general statistical consideration, not a claim that over-dispersion occurred in this trial.

The record does not report the handling of missing measurements, a primary analysis population, protocol deviations, or sensitivity analyses. These omissions limit the ability to assess how the reported summaries relate to all randomized participants and whether results were robust to alternative analysis decisions. No interim analyses or stopping rules are described; those details are not reported in the registry record.

10. Confidence Intervals and Precision

The posted interval for the headset video group versus the iPad group runs from -5.173 to 5.173 beats per minute around a mean difference of 0.0. For the VR game group versus the iPad group, the interval runs from -4.353 to 6.353 around a mean difference of 1.0. Each interval includes zero, so each is compatible with no difference in the group means as well as with differences in either direction within the stated bounds.

In general, a confidence interval conveys uncertainty around an estimated effect under the assumptions of the analysis. A wider interval indicates less precision than a narrower one, all else equal. The intervals show that the estimated contrasts are not pinned down to a single value. Their endpoints describe statistical uncertainty, not a range containing every participant’s outcome, and they do not by themselves identify which differences would matter clinically.

The record does not state the confidence level associated with these intervals or give the full procedure used to calculate them. The comparison summaries show standard errors for the group means, but no additional detail on interval construction. The interpretation should therefore remain tied to the reported limits rather than assume unreported methodological details.

The standard deviations of 16 in each group describe variability among measurements and are distinct from the uncertainty in a group mean or a between-group contrast. A group can have considerable individual variability while its estimated mean is more or less precise depending on the number of observations and analysis assumptions. The endpoint counts are 74, 73, and 64, respectively; the registry does not explain why these differ from the total enrollment of 226.

Precision is also outcome-specific. No intervals or estimates for the listed pain, anxiety, or satisfaction outcomes appear in the registry record. Thus, the heart-rate intervals cannot be used to infer the precision of those secondary outcomes.

11. Multiplicity, Missing Data and Analysis Populations

The registry lists one primary heart-rate outcome and three secondary outcomes: change in Visual Analogue Scale pain score, change in Visual Analogue Scale anxiety score, and parent or guardian post-procedure satisfaction. It also reports two primary-outcome comparisons against the iPad group. Because several outcomes and contrasts are listed, multiplicity is a relevant statistical consideration: in general, performing more tests can increase the chance of at least one apparently unusual result when all null hypotheses are true.

The record does not report a prespecified hierarchy, a family of tests, or any correction for multiple comparisons. The p-values attached to the primary comparisons are explicitly unadjusted. It is therefore unclear whether the investigators planned to interpret each contrast separately, whether one comparison had priority, or whether an adjustment was considered. No conclusion about the overall error rate of the study can be drawn from the reported p-values alone.

Missing-data handling and analysis populations are also not described. The registry reports total enrollment of 226 and primary-outcome group counts of 74, 73, and 64, but does not explain the relationship between those figures. It does not state whether the reported analyses included all randomized participants, only those with observed measurements, or another defined population. The reasons for any absent endpoint measurements are not reported in the registry record.

The registry lists the secondary outcomes but provides no numerical results for them, and it records zero analyses. Whether those outcomes were collected, whether data were missing, or whether analyses were performed but not posted is not reported in the registry record. The record also does not describe imputation, sensitivity analyses, or procedures for handling protocol deviations. These gaps matter because the interpretation of a randomized comparison depends not only on assignment but also on who contributes outcome data and how missing observations are treated.

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 adverse-event record gives separate group counts for serious events, other events, and deaths. It lists 76 participants at risk in the iPad video group, 80 in the headset video group, and 70 in the VR game group for both serious and other events. The number affected is recorded as 0 in each group for both categories, and deaths are recorded as 0 in each group. No serious-event terms are listed.

These figures describe what is posted in the registry; they do not establish that no event of any kind occurred outside the registry’s definitions, collection period, or reporting process. The record does not give event narratives, severity details beyond the serious-versus-other grouping, exposure duration, or a fuller account of how events were assessed. The adverse-event group sizes also differ from the primary-outcome counts, and the reason is not reported in the registry record.

There is a wording inconsistency in the adverse-event label for the headset video group, which calls it a VR video group, while the intervention and primary-outcome arm descriptions call it a non-VR video group. The record does not clarify whether this is only a labeling difference. The safety counts should be read as registry-reported group summaries, not as a complete characterization of the intervention experience.

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

The primary-outcome results show group mean heart-rate difference measures of 20 for the iPad video group, 20 for the headset video group, and 21 for the VR game group, with a standard deviation of 16 in each. The posted comparisons against the iPad group are small in relation to the uncertainty represented by their intervals, and both intervals include zero. These findings describe the reported heart-rate outcome in this record.

They do not establish that the groups are equivalent, because no equivalence margin or non-inferiority margin is reported. A result that does not distinguish an estimate from zero is not proof of no effect. The intervals allow a range of possible between-group differences, and the registry does not state which differences would be important for the intended clinical or research interpretation.

The endpoint is a physiologic surrogate identified by the study description as related to pain and anxiety. A heart-rate result is not interchangeable with a participant’s reported pain or anxiety, nor does it directly measure satisfaction. Although these outcomes are listed, their numerical results are not reported in the registry record. No conclusion about those patient-reported outcomes follows from the posted heart-rate comparisons.

The results also do not show a direct numerical contrast between the VR game and the headset video group. The posted estimates compare each of those groups with the iPad group. No inference about the relative difference between the two headset conditions should be substituted for an unreported comparison.

Finally, the registry does not report the detailed statistical analysis plan, handling of missing data, or the primary analysis population. Those limitations mean that the estimates can be interpreted as posted summaries, but not as a complete account of all analyses or all randomized participants. The findings are neither a general statement about virtual reality in other settings nor a basis for individual treatment decisions.

14. Why This Trial Matters Statistically

This trial is statistically informative because it sets up three distraction conditions in the same broad procedural setting: a non-VR video on an iPad, a non-VR video through a headset, and a VR game through a headset. Comparing these approaches raises a useful design question: whether observed differences might relate to immersion, the headset format, or the specific distraction content. The posted primary results, however, give contrasts against the iPad group and do not report a numerical comparison between the two headset groups.

The use of both a physiologic primary outcome and patient-reported secondary outcomes also highlights an important measurement distinction. In general, objective physiologic measures and participants’ own reports can capture different aspects of an experience. The registry identifies heart rate as a surrogate related to pain and anxiety, while separately naming pain and anxiety ratings and satisfaction. Because the secondary numerical results are absent, the posted record does not permit a joined interpretation of these distinct outcome types.

The results illustrate why an estimate should be read together with its uncertainty. The mean differences are accompanied by intervals that span zero and allow differences in either direction. The planning illustrations based on the observed effect also show, under their stated assumptions, how sample-size requirements depend on the effect one aims to detect. Those illustrations are not the trial’s design justification and are not observed power.

At the same time, missing reporting on the analysis plan, analysis populations, and secondary outcomes limits statistical appraisal. Randomized design is important, but understanding the result also requires knowing how assignment was implemented, how outcome data were handled, and which analyses were planned. Those details are not reported in the registry 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 registry provides limited detail on the trial’s statistical methods. It does not report the randomization sequence, allocation concealment, a protocol-level analysis plan, a sample-size justification, or interim analyses. It records no masking, but does not describe whether measurement or analysis personnel knew group assignment. These omissions prevent a full assessment of how the study was conducted and how the posted contrasts were selected.

The total enrollment is 226, while the primary-outcome counts are 74, 73, and 64 across the three groups. The record does not explain the difference or identify the analysis population. It also does not describe missing-data procedures, participant exclusions, protocol deviations, or sensitivity analyses. This leaves uncertainty about whether the reported group summaries represent all randomized participants or only those with available measurements.

Only the heart-rate outcome has numerical group results and comparison estimates in the record. The pain, anxiety, and satisfaction outcomes are named but their results are not reported in the registry record. The stated endpoint title uses absolute difference, but the subtraction convention is not specified. The stated timeframe also includes an upper limit of up to 20 minutes while describing heart-rate measurement through one minute after the procedure; the record does not further explain this phrasing.

The adverse-event group label for the headset video condition differs from the intervention and arm wording, and the registry does not clarify the discrepancy. Finally, the results are specific to the listed outpatient pediatric orthopedic procedures and the described distraction conditions. The record does not provide information to assess generalizability to other procedures, populations, or implementations.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Virtual Reality Distraction During Outpatient Pediatric Orthopedic Procedures — NCT05510232.
• Registry record last updated 2025-01-31; status last verified 2025-01.
• Results first posted 2025-01-31.
• 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

This completed randomized, parallel-group study compared three forms of visual distraction during outpatient pediatric orthopedic procedures. The primary endpoint was the absolute difference in heart rate from three minutes before the procedure to the maximum measured during the procedure through one minute afterward. The posted group means were 20 for iPad video, 20 for headset video, and 21 for the VR game, with a standard deviation of 16 in each group.

Against the iPad group, the headset video mean difference was 0.0, with an interval from -5.173 to 5.173 and an unadjusted p-value of 1.0. The VR game mean difference was 1.0, with an interval from -4.353 to 6.353 and an unadjusted p-value of 0.714. Both intervals include zero. Numerical results for the listed secondary outcomes, detailed analysis methods, and explanations of the outcome-count differences are not reported in the registry record.