Validation of a Knee Brace for Gonarthrosis: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Validation of a Knee Brace for Gonarthrosis (NCT05814471), a randomized na study. The primary outcome is Ease of Use Measurement Scale.

2. Clinical Question

3. Trial Design

The registry identifies this as a randomized, unmasked crossover study, with a total enrollment of 5 and a completed status. The record gives the start date as 2023-03-30 and the primary completion date as 2023-09-27. The sponsor is TOPMED, and the listed phase is NA. The study concerns gonarthrosis and the clinical validation of a valgus knee brace.

In a crossover design, participants receive more than one condition in sequence, so each participant may contribute observations under multiple conditions. The registry describes an initial adjustment period with a new brace using Velcro straps, followed by intervention periods with the cable system and Velcro system. It lists both possible orders: adjustment period followed by cable and then Velcro, or adjustment period followed by Velcro and then cable. The description says each intervention period lasts 14 days. The method used to generate or conceal the randomized sequence is not reported in the registry record.

The posted outcome values are reported separately for Cable Fastening System, Velcro Straps, and Adjustment Period (Velcro-14 Days), with n=5 for each. These labels identify conditions and should not be read as three independent parallel groups: the design is explicitly crossover. The registry does not provide participant-level paired data or explain how the reported summaries account for within-participant measurements. It also does not describe whether order or period effects were incorporated into an analysis.

The registry lists 8 outcome measures and reports no posted analyses. A phase designation of NA is not an indication of study quality or a statistical result; it is the phase value recorded for this device study.

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: Total enrollment was 5 participants, since participants did all interventions in a sequence, the total amount of participants for each intervention was 5 since there were no exclusions nor drop-outs.

Adjustment Period(14 Days)

First Intervention(14 Days)

Second Intervention(14 Days)

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 Ease of Use Measurement Scale, measured over Before the 2 weeks of intervention with each brace, assessed after a brace fitting protocol and a few minutes of wearing the intervention brace..

The primary endpoint is the Ease of Use Measurement Scale, a study-developed continuous score intended to capture perceived ease of using the brace. The record says the score averages five items, each rated on a 5-point scale, with 1 meaning harder to use and 5 meaning easier to use. A higher score therefore represents easier use according to the scale’s stated direction. The record does not report validation characteristics for the scale.

The stated timeframe is before the two weeks of intervention with each brace, after a brace-fitting protocol and a few minutes of wearing the intervention brace. That timing matters for interpretation: these values describe the assessment after fitting and brief wear, not an outcome explicitly measured after completing each 14-day intervention period. The registry does not report a separate primary measure of longer-term comfort, installation effort, physical treatment efficacy, or psychological treatment efficacy.

The results are means with standard deviations. The cable-fastening condition has a reported mean of 4.05 and standard deviation of 0.26; the Velcro condition has a mean of 3.0 and standard deviation of 1.21; and the adjustment-period condition has a mean of 4.05 and standard deviation of 0.78. These are descriptive summaries. No confidence intervals, hypothesis tests, or adjusted comparisons are reported for this endpoint.

Using a continuous score preserves gradations in participants’ ratings rather than reducing them to a binary category. However, a mean alone does not show each participant’s rating pattern, and a standard deviation does not describe the pairing or sequence of observations in this crossover study.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

For the primary outcome, the registry reports a mean and standard deviation for each listed condition. A mean describes the arithmetic center of the recorded scores. The standard deviation describes how dispersed scores are around that mean. These summaries are useful for understanding the observed score distributions at a broad level, but they do not show the individual observations or the relationship between repeated observations from the same participant.

Why does the crossover design matter?

General statistical explanation: In a crossover study, conditions are experienced in sequence rather than assigned only once to separate groups. When the same participant contributes data under multiple conditions, measurements from that person are generally related. A comparison can use this pairing, which may account for stable differences between participants. An analysis that ignores pairing may misrepresent uncertainty. The registry record identifies a crossover design but does not report the statistical model or whether the analysis used paired observations.

Sequence and period can also matter. A period effect is a systematic change associated with when a condition is received, while a sequence effect can arise when the order of conditions is relevant. Carryover refers to effects of an earlier condition that persist into a later period. These are general issues for crossover analyses; their presence or handling in this study is not reported in the registry record. The described adjustment period and alternate orders provide context, but do not establish that carryover was prevented or that period effects were assessed.

What does a standard deviation tell the reader?

General statistical explanation: A standard deviation summarizes variation among observed values around their mean, in the same measurement units as the outcome. A relatively concentrated set of scores can have a smaller standard deviation, while more variable scores can have a larger one. It is not a confidence interval and does not directly express how precisely a treatment contrast has been estimated. For a crossover comparison, the variation in within-person differences can be particularly relevant; the registry does not report that quantity.

The score is continuous and bounded by the scale description, with 1 indicating harder use and 5 indicating easier use. The record reports means, but does not state whether the analysis treated the score as continuous in a particular model, checked its distribution, or used any alternative method. No such choices should be inferred from the descriptive statistics alone.

How should uncertainty be evaluated?

General statistical explanation: A confidence interval gives a range of estimates compatible with the data and the method’s assumptions. Its width reflects uncertainty, including the amount of information and variability in the data. It is not a guarantee that the true value lies within a particular calculated interval. No confidence intervals for the primary outcome or condition contrasts are reported in the registry record. No p-values or test results are reported either. Consequently, statistical significance and the precision of any contrast cannot be read from the posted means and standard deviations alone.

The study’s small reported enrollment means that estimates may be sensitive to individual observations, but the registry does not provide individual-level data with which to assess that sensitivity. This is a general caution about interpreting descriptive summaries from a small study, not a calculation of the study’s power or a statement about its actual effect. No observed-power calculation is reported.

What are planning sample sizes intended to show?

General statistical explanation: A sample-size illustration asks how many participants might be needed under stated assumptions to detect an effect at a specified significance level and power. The registry’s planning assumptions describe two-sided significance level 0.05, equal allocation, a normal approximation, and effects expressed as stated fractions of the observed effect. Such calculations are planning illustrations, not observed power and not evidence that a future study will achieve a particular result. The record does not report the trial’s own design justification or a prospective sample-size target beyond the enrollment listed. For a crossover study, planning also depends on the within-participant variability and correlation; the registry record does not report those quantities.

The registry identifies no posted analyses, so a reader cannot determine whether the primary summaries result from a prespecified statistical procedure or whether any adjustments were made. A sound interpretation keeps the descriptive summaries separate from inference: means and standard deviations describe the recorded outcome values, while claims about comparative uncertainty would require a reported analysis appropriate to the repeated-measures design.

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("Cable Fastening System", "Velcro Straps", "Adjustment Period(Velcro-14 Days)")
n   <- c(5, 5, 5)
m   <- c(4.05, 3, 4.05)
sp  <- c(0.26, 1.21, 0.78)
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  Cable Fastening System  5  4.050  0.260  3.727  4.373
CARM  Velcro Straps  5  3.000  1.210  1.498  4.502
CARM  Adjustment Period(Velcro-14 Days)  5  4.050  0.780  3.082  5.018

11. Multiplicity, Missing Data and Analysis Populations

The registry lists 8 outcome measures, while the primary outcome identified in the record is the Ease of Use Measurement Scale. It reports 0 posted analyses and 0 posted secondary outcomes. The registry does not describe a multiplicity strategy, such as a hierarchy of outcomes or an adjustment for multiple testing. Without posted inferential analyses, there are no reported p-values to evaluate for multiplicity. It is also not reported in the registry record whether any outcomes or analyses were selected after data collection.

Missing-data handling is not reported in the registry record. The posted condition summaries each give n=5, but that alone does not establish how missing observations were handled, whether all enrolled participants contributed to every measure, or whether any imputation or other procedure was used. The record does not describe an analysis population, exclusions, protocol deviations, or a rule for including observations in the endpoint summaries.

For a crossover design, missing observations can affect paired comparisons differently from summaries that treat each condition separately. If a participant has an observation in one period but not another, the availability of complete within-person comparisons may differ from the condition-specific counts. The registry does not give participant-level completeness or explain how incomplete sequences would be handled. These are general considerations, not evidence that missing data occurred in this study.

The record also does not report a statistical analysis plan, methods for sensitivity analyses, or a prespecified approach to the repeated observations. In their absence, the posted means and standard deviations should be interpreted as descriptive rather than as a complete account of the intended analysis.

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 safety record lists serious adverse events, other adverse events, and deaths separately for the cable-fastening condition, Velcro condition, and adjustment period. For each listed condition, 5 participants are reported at risk for serious adverse events and 0 are reported as affected. For other adverse events, 5 are listed at risk and 0 as affected. Deaths are reported as 0 for each condition.

These are registry counts, not estimates of comparative safety. The record does not provide event descriptions because no serious-event terms are listed, and it does not give an analysis comparing conditions. In a crossover study, participants may be represented under more than one condition; the condition-specific entries should not be added together or treated as independent participant groups. The registry does not explain how events were attributed across periods or how the at-risk counts were defined.

Zero reported events in this record means that no affected participants are listed for these categories in the posted results. It does not establish that the risk of an event is absent, nor does it provide precise estimates of uncommon harms. The small enrollment and the lack of event-level detail limit what can be concluded from these counts. No additional safety conclusions are supported by the registry record.

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

The posted results give a descriptive snapshot of ease-of-use scores under the recorded brace conditions. The cable-fastening system has a mean score of 4.05, the Velcro straps system has a mean of 3.0, and the adjustment period has a mean of 4.05. Because higher scores on the scale mean easier use, these values show the direction of the observed ratings. Their standard deviations indicate the recorded spread, with 0.26 for cable fastening, 1.21 for Velcro straps, and 0.78 for the adjustment period.

These summaries do not show whether differences are statistically distinguishable from sampling variation. No confidence intervals, p-values, or model-based contrasts are reported. Nor do the summaries reveal how each participant’s scores changed across conditions, which is important in a crossover design. The registry does not report a threshold defining a meaningful difference on this study-developed scale, so the practical importance of any score contrast cannot be determined from the means alone.

The timing means the endpoint is an assessment after fitting and a few minutes of wearing the intervention brace, before the two weeks of intervention. It does not establish how ease of use changed over the full intervention period. The record’s broader description mentions comfort, installation, and physical and psychological treatment efficacy, but the posted primary outcome addressed in these results is ease of use. The registry record does not report results for those broader concepts in the primary endpoint.

The findings also do not establish effectiveness of a brace for gonarthrosis, superiority of one fastening system, or effects in populations beyond the participants represented in the record. The design and descriptive results can inform questions for further study, but the absence of reported inferential methods and the limited enrollment constrain generalization. The safety counts likewise describe what is listed in the registry; they cannot rule out unobserved or uncommon events.

14. Why This Trial Matters Statistically

This study is statistically notable because it uses a crossover design to compare fastening conditions for the same brace. Such designs can be informative when each participant experiences multiple conditions, since within-person comparisons may separate condition differences from stable differences between people. That advantage depends on suitable measurement and analysis. The registry confirms randomization and crossover structure, but does not report a paired analysis, a model for period or sequence, or participant-level results.

The study also illustrates why endpoint timing and endpoint meaning must be read carefully. The scale is intended to capture ease of use, and its direction is clear: higher values indicate easier use. But the recorded assessment takes place after fitting and brief wear, before the two-week intervention periods. A score at this point answers a narrower question than sustained use over the intervention period. Clear measurement timing prevents the score from being interpreted as a longer-term outcome that it does not represent.

The reported means and standard deviations are useful descriptive information, but a small enrolled sample and absent uncertainty estimates leave comparative precision unresolved. Repeated measurements make participant-level pairing and the variability of within-person differences especially relevant. Without those details, a simple comparison of the reported means cannot capture the full statistical structure.

Finally, the registry lists 8 outcome measures but posts no analyses or secondary results. This makes the distinction between registered outcomes and reported inferential evidence important. The record supports a limited description of the observed primary scores and safety counts; it does not provide a statistical basis for a definitive comparative conclusion. These design and reporting features make the study a useful example of why descriptive results, crossover methods, endpoint timing, and uncertainty should be considered together.

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 record leaves several trial-specific details unclear. It does not report participant eligibility criteria, baseline characteristics, or the method used to generate and conceal randomized sequences. Although two condition orders are described, the record does not say how participants were assigned to them or whether the sequence groups were balanced.

The primary scale was developed for this study, but psychometric properties, validation evidence, and a threshold for meaningful change are not reported in the registry record. The scale averages five items rated on a 5-point system, yet item-level results and individual participant scores are not posted. The stated assessment occurs after fitting and a few minutes of wear, before the two-week intervention periods, limiting interpretation as a measure of experience over the full period.

The registry provides condition-specific means and standard deviations but no paired contrasts, confidence intervals, p-values, or statistical model. It does not describe handling of period, sequence, carryover, or within-participant correlation. Missing-data procedures and analysis populations are also not reported. Although n=5 is listed for each condition, the record does not show the completeness of repeated measurements or how those observations were analyzed.

The record lists 8 outcome measures, but no posted analyses or secondary results. It does not report a multiplicity approach or explain whether outcomes and analyses were prespecified. The enrollment is 5; no trial-specific sample-size justification is reported. Taken together, these limitations mean that the posted data support descriptive interpretation, while the uncertainty and broader applicability of condition comparisons remain unresolved.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Validation of a Knee Brace for Gonarthrosis — NCT05814471.
• Registry record last updated 2025-07-29; status last verified 2025-07.
• Results first posted 2025-07-29.
• 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 completed study is a randomized, unmasked crossover evaluation of a valgus knee brace for gonarthrosis, sponsored by TOPMED. Enrollment was 5. The registry describes an adjustment period using Velcro straps followed by 14-day intervention periods using cable fastening with 3D-printed straps and Velcro straps, with the order of the intervention conditions varying between the described sequences.

The primary outcome is a study-developed Ease of Use Measurement Scale, assessed after fitting and brief wear before the intervention periods. Reported means are 4.05 for cable fastening, 3.0 for Velcro straps, and 4.05 for the adjustment period; the corresponding standard deviations are 0.26, 1.21, and 0.78. The registry reports no posted analyses, confidence intervals, or p-values. Safety entries list 0 serious adverse events, 0 other adverse events, and 0 deaths for each condition. The record supports descriptive reporting, but does not provide inferential comparisons or detail the analysis of repeated measurements.