Iterative Design of Custom Dynamic Orthoses: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Iterative Design of Custom Dynamic Orthoses (NCT04800510), a randomized na study. The primary outcome is Joint Contact Stress-Time Exposure.

2. Clinical Question

3. Trial Design

This is a randomized, single-masked crossover study. The registry record lists the phase as NA and the status as completed. Enrollment was 9. The recorded start date is 2021-04-21, and the primary completion date is 2022-06-25.

In a crossover design, participants are assessed under more than one condition, so each participant can contribute measurements under the comparator and intervention conditions. The primary outcome description states that each participant completed testing in NoCDO, CDOA, CDOB, and CDOC. This repeated-measures structure is important when interpreting the posted condition means: the conditions are not described as independent groups of different participants.

The registry describes sequences beginning with NoCDO and then varying the order of CDOA, CDOB, and CDOC. Allocation is listed as randomized. The record does not explain the randomization procedure or how sequence assignments were implemented. It identifies masking as single but does not report who was masked or how masking was maintained.

The intervention is a device: a carbon fiber custom dynamic orthosis. The study rationale describes varying brace geometry to examine ankle forces and to refine a pre-existing musculoskeletal model and procedures for combining data sources. Washout periods, the timing of assessments, adherence procedures, and whether period or carryover effects were considered are not reported in the registry record.

The registry describes the primary outcome timeframe as Baseline, while also stating that participants completed testing in all conditions. The meaning of that timeframe in relation to the condition-specific summaries is not further explained in the registry record. The record does not report a sample-size justification or a statistical analysis plan.

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

Analysis population for the primary outcome, as defined in the registry: Each of the study participants completed testing in all conditions: NoCDO, CDOA, CDOB, CDOC

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.

Population: No study participants were randomized to testing order NoCDO, CDOA, CDOB, CDOC

Only the first 6 of 7 groups are shown.

6. Primary Endpoint

The registry lists the primary outcome as Joint Contact Stress-Time Exposure, measured over Baseline.

The primary endpoint is joint contact stress-time exposure, reported in MPa-s/gait cycle. It is a continuous measure estimated with a participant-specific musculoskeletal model that includes surface geometry of each participant’s tibia and talus. The registry description says contact stress-time exposure was calculated at 13 points across the gait cycle and that higher values indicate greater exposure.

This endpoint is used to represent ankle articular contact loading over the gait cycle, rather than relying only on a single peak value. The study’s stated rationale is to assess how changes in brace geometry relate to forces across the ankle joint and to refine the model and procedures used to estimate ankle articular contact stresses. It is a model-based estimate, not a direct clinical outcome such as pain, function, or injury.

The registry reports a mean and standard deviation for each condition. The NoCDO mean is 3.9 with a standard deviation of 2.9; the CDOA mean is 3.5 with a standard deviation of 2.7; the CDOB mean is 4.1 with a standard deviation of 2.9; and the CDOC mean is 2.7 with a standard deviation of 0.6. Confidence intervals and inferential comparisons are not reported in the registry record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

What does the mean describe?

The primary measure is continuous, and the registry specifies the mean as its summary parameter. A mean gives the average recorded value for a condition. Here, the reported condition means are 3.9 for NoCDO, 3.5 for CDOA, 4.1 for CDOB, and 2.7 for CDOC. The unit is MPa-s/gait cycle. A mean is useful for describing the central level of a measurement, but it does not show how much individual values vary or how certain a comparison between conditions is.

What does the standard deviation describe?

The registry reports standard deviations of 2.9 for NoCDO, 2.7 for CDOA, 2.9 for CDOB, and 0.6 for CDOC. General statistical explanation: a standard deviation describes the spread of observations around their mean. A larger standard deviation indicates more dispersion in the measured values within that condition; it is not a measure of uncertainty in a comparison between condition means. The standard deviation is also not a confidence interval.

Why does the crossover design matter?

General statistical explanation: in a crossover study, the same participant receives or is assessed under multiple conditions. Analyses can use within-participant contrasts, which account for each participant serving as their own comparison. Such analyses need the participant-level links between condition measurements. The registry reports the condition means and standard deviations, but does not report paired differences or an inferential model. The marginal summaries alone cannot reconstruct the variability of the within-participant contrasts.

Order can also matter in crossover studies. General statistical explanation: measurements may be affected by the period in which a condition is assessed, by learning or fatigue, or by effects that persist from a previous condition. The registry lists randomized sequences, but does not report whether period or carryover effects were assessed, or whether a washout period was used. The available record therefore does not establish how these potential design considerations were handled.

What would inferential analysis add?

General statistical explanation: an inferential comparison would estimate a condition contrast and quantify uncertainty, commonly with a confidence interval and a test statistic or p-value. A confidence interval indicates a range of values compatible with the data under the analysis assumptions; it helps show the precision of an estimate. None is reported for the condition comparisons in this record, and the analysis count is 0. The posted summaries should not be read as though they were adjusted comparisons or hypothesis tests.

General statistical explanation: a crossover analysis would ordinarily account for the repeated measurements within participants rather than treating the condition summaries as unrelated groups. The exact analysis depends on the design and data structure. The statistical model, assumptions, handling of sequence and period, and analysis population are not reported in the registry record, so no particular method can be attributed to this study.

How should variability be considered?

General statistical explanation: variability affects precision. When measurements are highly dispersed, a mean can be an incomplete description of the observed values, and an estimated contrast may be less precise. In repeated-measures data, the association between measurements from the same participant also matters. The reported standard deviations describe dispersion within each condition, but do not provide the correlations between conditions or the standard deviation of paired differences.

General statistical explanation: over-dispersion means that observed variability is greater than a model expects. It matters because a model that understates variability can produce overly narrow confidence intervals and misleading tests. The registry does not report a model or an over-dispersion assessment for this continuous outcome. There is no basis to say that over-dispersion was present or that any adjustment was used.

What can be concluded from the posted summaries?

The summaries support a descriptive statement about the observed means and standard deviations for each condition. They do not provide precision estimates for condition contrasts, establish statistical significance, or account visibly for the crossover pairing. No recalculated comparison is reported, and the record does not include an inferential analysis that could take precedence over a simple descriptive reading.

General statistical explanation: planning calculations based on observed effects, when available, are illustrations of sample sizes under specified assumptions. They are not observed power and do not substitute for an analysis of the trial results. A sample-size justification for this study is not reported in the registry record.

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("NoCDO", "CDOA", "CDOB", "CDOC")
n   <- c(9, 9, 9, 9)
m   <- c(3.9, 3.5, 4.1, 2.7)
sp  <- c(2.9, 2.7, 2.9, 0.6)
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  NoCDO  9  3.900  2.900  1.671  6.129
CARM  CDOA  9  3.500  2.700  1.425  5.575
CARM  CDOB  9  4.100  2.900  1.871  6.329
CARM  CDOC  9  2.700  0.600  2.239  3.161

11. Multiplicity, Missing Data and Analysis Populations

The registry lists 25 outcome measures and 15 posted secondary outcomes. The primary outcome is joint contact stress-time exposure. Listed secondary outcomes include ankle range of motion, peak ankle moment, peak ankle power, plantar force for the total foot and foot regions, and the Four Square Step Test. The registry reports 0 analyses. Numerical results for the secondary outcomes and inferential results for the primary outcome are not reported in the registry record.

When a study assesses multiple outcomes or makes multiple comparisons, the chance of at least one false-positive finding can increase if each test is interpreted independently. General statistical explanation: multiplicity procedures can address this issue by controlling an error rate or by organizing analyses into prespecified primary and secondary questions. The registry record does not report a multiplicity strategy, a hierarchy among secondary outcomes, or which comparisons were prespecified.

The outcome descriptions identify the condition assessments, and the primary outcome summary reports n = 9 for each condition. The registry does not explain how missing measurements, if any, were handled, whether all recorded observations were included in each summary, or whether any imputation was performed. It also does not report an analysis population definition beyond the statement that each participant completed testing in all conditions. The handling of missing data and the analysis population are therefore not reported in the registry record.

These omissions limit interpretation of the posted statistics. Without analysis details, it is not possible to determine how multiple outcomes were addressed or whether missingness affected the summaries.

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.

For each condition, the registry lists 9 participants at risk for serious adverse events and 0 serious adverse events. It also lists 9 at risk for other adverse events and 0 other adverse events. Deaths are recorded as 0 for each condition.

These are the registry’s recorded safety figures for NoCDO, CDOA, CDOB, and CDOC. A count of 0 means that no events are reported in that category in the posted record; it does not show that the study could rule out uncommon harms. The registry does not report further detail about adverse-event collection, the observation period, event definitions, or how events were attributed to a condition. The figures should therefore be read as the recorded counts, not as proof that no adverse events could occur.

Because the study uses repeated conditions in the same participants, the condition-specific at-risk entries describe assessments across the crossover conditions, not separate independent groups. No serious adverse-event terms are listed.

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

The results establish that the registry reports different condition-specific means for the model-estimated joint contact stress-time exposure. The posted means are 3.9 for NoCDO, 3.5 for CDOA, 4.1 for CDOB, and 2.7 for CDOC. The reported standard deviations show that the observed spread also differs across conditions, with the CDOC standard deviation reported as 0.6 and the other condition standard deviations as 2.9, 2.7, and 2.9 respectively.

Those figures are descriptive summaries, not proof that one orthosis geometry changes ankle loading. The registry does not report a statistical test, confidence interval, or paired condition contrast. Without those analyses, the precision of the observed differences cannot be judged. The record also does not report a threshold for interpreting the size of a difference as important, so the clinical meaning of the mean contrasts is not established.

The primary endpoint is a model-based measure of contact stress-time exposure across the gait cycle. It is not a direct report of symptoms, daily function, injury, or long-term outcomes. The study rationale describes refinement of a musculoskeletal model and procedures for combining data sources. Consequently, these results should be understood in that measurement and modeling context rather than as evidence about broader clinical outcomes.

The record does not establish that any brace condition is superior, nor does it establish that the conditions are equivalent. It also does not permit conclusions about durability, safety beyond the recorded adverse-event counts, or effects in populations beyond those enrolled. The most defensible reading is that the registry posts condition-level summaries from a small crossover study but does not report inferential analyses to quantify uncertainty in comparisons.

14. Why This Trial Matters Statistically

This study is statistically notable for its crossover structure and model-based primary endpoint. Each participant is described as completing testing without a custom dynamic orthosis and with each of the brace variants. That repeated-measures structure makes within-participant comparisons central to the design and highlights why condition means alone are not enough to evaluate uncertainty.

The endpoint is also a constructed estimate based on a participant-specific musculoskeletal model, including tibia and talus surface geometry and measurements across the gait cycle. Model-based outcomes can provide a way to examine biomechanical quantities that are not captured by a single conventional clinical measure. At the same time, interpretation depends on how the model and inputs are specified and validated. Such validation details are not reported in the registry record.

The registry provides means and standard deviations but no inferential analyses. This makes a useful distinction between descriptive results and statistical evidence: observed variation across conditions is visible in the summaries, while uncertainty in the paired contrasts remains unquantified. The record therefore illustrates why a clear analysis plan and reporting of paired estimates, confidence intervals, and handling of repeated measurements matter in crossover studies.

The study’s stated aim includes refining the model and procedures, so the work has a methodological dimension as well as a comparison of orthosis conditions. The posted record does not establish whether the design or analysis was intended primarily as feasibility, model development, or hypothesis testing. That purpose and a sample-size justification 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.

Enrollment was 9, and the registry reports no inferential analyses for the primary outcome. The condition summaries do not include confidence intervals, p-values, or paired contrasts, which limits assessment of precision and uncertainty. The standard deviations describe condition-level spread but do not show how measurements from the same participant relate across conditions.

The record identifies the endpoint as an estimate from a participant-specific musculoskeletal model. It does not report model validation, sensitivity analyses, or details sufficient to evaluate how the model’s assumptions influence the estimates. The endpoint description also uses the timeframe Baseline, while the primary population description says participants completed testing in all conditions; the relation between this timeframe label and the condition summaries is not clarified.

Details of the single masking, randomization procedure, assessment timing, washout, period effects, and carryover are not reported in the registry record. The population is labeled Adult ALL and Healthy, but participant characteristics and the composition of the enrolled sample are not reported in the record. Generalizability beyond this enrolled sample cannot be established from the posted summaries.

The record lists multiple outcomes but does not report a statistical analysis plan, multiplicity handling, missing-data methods, or an analysis population definition. Numerical results for the listed secondary outcomes are not reported in the registry record. Safety reporting includes zero recorded events in the listed categories, but the observation period and event-collection procedures are not described. These limitations constrain interpretation of both the outcome summaries and the safety counts.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Iterative Design of Custom Dynamic Orthoses — NCT04800510.
• Registry record last updated 2026-01-30; status last verified 2023-12.
• Results first posted 2023-12-05.
• 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 crossover study of carbon fiber custom dynamic orthoses. Enrollment was 9, and the primary endpoint was model-estimated joint contact stress-time exposure, reported as a mean and standard deviation in MPa-s/gait cycle for NoCDO, CDOA, CDOB, and CDOC.

The posted means are 3.9, 3.5, 4.1, and 2.7, respectively. The registry reports 0 analyses, and no inferential comparisons or confidence intervals are reported. The condition summaries are descriptive and do not establish the precision or statistical significance of differences. Recorded adverse-event counts are 0 for serious events, other events, and deaths in each condition. Further analysis, missing-data, and model-validation details are not reported in the registry record.