This page provides an independent statistical analysis and educational interpretation of publicly reported results. ClinicalTrials.gov provides the official trial registry record. Numerical trial results on this page are restricted to the results posted in the ClinicalTrials.gov record; calculations added by Clinical Biostats are labelled as such.
1. Trial at a Glance
This page covers the registry results for Effects of Two Different Types of Ankle Foot Orthoses on Gait Outcomes in Patients With Subacute Stroke. (NCT02693834), a randomized na study. The primary outcome is Gait Endurance.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT02693834 |
| Phase | NA |
| Condition | Stroke, CVA, Hemiplegia |
| Allocation | Randomized |
| Design model | Crossover |
| Masking | None (open label) |
| Enrollment | 23 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Texas Woman's University |
| Results posted | Yes |
2. Clinical Question
Population
The intended population was adults with a first-time unilateral stroke, 4 - 20 weeks after stroke onset, with hemiparesis and foot drop. The registry summary also describes eligibility requirements related to following commands and walking with or without an assistive device. Enrollment was 23.
Intervention
One device was a Double Adjustable AFO. Participants were assigned to practice with one type of AFO for a week, followed by practice with the other type for another week. The registry describes both possible practice sequences.
Comparator
The comparison was with a Posterior Leaf Spring AFO. Both devices were assessed during gait testing, and the order of the devices at the first visit was described as random. The record also describes random assignment of the initial practice device.
Primary question
The stated primary measure was gait endurance, assessed with the Six Minute Walk test in meters. The primary outcome description specifies measurement at baseline using the Double Adjustable AFO. The study purpose also describes comparing gait outcomes with the two devices and examining whether a week of practice changes those outcomes. The registry record does not report outcome values or an estimate of the difference between devices.
The main statistical question is therefore whether the recorded gait-endurance measurements distinguish performance with the two AFO types, and how precisely any difference is estimated. The registry record identifies a crossover design, in which participants are assigned sequences and can be measured under both device conditions. That design can support within-participant comparisons, but interpretation depends on the actual analysis and reported results. Neither the primary outcome results nor the statistical analysis used for that comparison is reported in the registry record.
3. Trial Design
This was a completed, randomized crossover study sponsored by Texas Woman's University. The registry lists an enrollment of 23, allocation as randomized, and masking as none. The study is listed as starting in 2016-01, with primary completion in 2018-04. The phase is listed as NA.
The two devices were the Posterior Leaf Spring AFO and the Double Adjustable AFO. The registry describes two practice sequences: Posterior Leaf Spring AFO followed by Double Adjustable AFO, or the reverse. Each practice period is described as one week. The brief summary says data were to be collected three times over a two-week period. It also describes a first visit with assessments and gait testing using both AFO types in a random order, followed by assignment of one type of AFO for practice. The complete schedule and the relationship between all measurement visits and practice periods are not reported in the registry record.
The stated inclusion description calls for twenty participants over the age of 18, of any gender and ethnicity, with first-time unilateral stroke 4 - 20 weeks after onset, hemiparesis, and foot drop. The registry also lists exclusions, including inability to walk the specified distance with the required assistance level, inability to follow two-step commands, cerebellar stroke, inability to ambulate before stroke, and receiving chemotherapy. These are descriptions of the study eligibility criteria, not evidence that every enrolled participant completed every assessment.
Random allocation and a crossover structure describe how conditions were assigned, not how the outcomes were statistically analyzed. The statistical model, handling of order or period effects, and analysis population are not reported in the registry record. No masking was used according to the registry.
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: Of the 23 consented participants 2 dropped out at baseline due to fatigue. 21 people completed the baseline measurements. 11 were randomized to DA AFO first week group, PLS AFO second week(1 lost to follow up) and 10 were randomized to PLS AFO first week, and DA AFO second week. 20 participants completed both arms.
Baseline Measurement
| Stage | PLS AFO First Then DA AFO | DA AFO First Then PLS AFO |
|---|---|---|
| STARTED | 12 | 11 |
| COMPLETED | 10 | 11 |
| NOT COMPLETED | 2 | 0 |
Reasons for not completing this period:
| Reason | PLS AFO First Then DA AFO | DA AFO First Then PLS AFO |
|---|---|---|
| Withdrawal by Subject | 1 | 0 |
| Adverse Event | 1 | 0 |
Week 1 Practice
| Stage | PLS AFO First Then DA AFO | DA AFO First Then PLS AFO |
|---|---|---|
| STARTED | 10 | 11 |
| COMPLETED | 10 | 11 |
| NOT COMPLETED | 0 | 0 |
Week 2 Practice
| Stage | PLS AFO First Then DA AFO | DA AFO First Then PLS AFO |
|---|---|---|
| STARTED | 10 | 11 |
| COMPLETED | 10 | 10 |
| NOT COMPLETED | 0 | 1 |
Reasons for not completing this period:
| Reason | PLS AFO First Then DA AFO | DA AFO First Then PLS AFO |
|---|---|---|
| Adverse Event | 0 | 1 |
Analysis population for the primary outcome, as defined in the registry: 6MWT using DA AFO
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.
| Characteristic | Unit | Ankle Foot Orthosis |
|---|---|---|
| Participants analysed | 20 | |
| Age, Categorical: <=18 years | Participants | 0 |
| Age, Categorical: Between 18 and 65 years | Participants | 16 |
| Age, Categorical: >=65 years | Participants | 4 |
| Sex: Female, Male: Female | Participants | 9 |
| Sex: Female, Male: Male | Participants | 11 |
| Race and Ethnicity Not Collected | Participants | — |
| Mini Mental State exam | units on a scale | 29.2 (SD 1.0) |
6. Primary Endpoint
The registry lists the primary outcome as Gait Endurance, measured over at baseline.
| Element | Registry entry |
|---|---|
| Result type | Mean |
| Measure of spread | Standard Deviation |
| Unit | Meter |
| Endpoint classification | Continuous Endpoint |
The primary outcome is titled Gait Endurance. It is a continuous measure reported in meters, with the registry identifying the mean and standard deviation as its summary form. The measure is the Six Minute Walk test, described as assessing gait endurance. The primary outcome entry specifies the baseline timeframe and identifies use of the Double Adjustable AFO.
As a general explanation, a walking-distance measure over a fixed test duration provides a quantitative way to describe how far a participant walks during that assessment. A continuous outcome can be summarized by its mean to describe the group’s average and by its standard deviation to describe variation among participants. These summaries do not, by themselves, show whether a difference between conditions is statistically distinguishable from sampling variation.
The study purpose also refers to comparing gait outcomes with both AFO types and to whether one week of practice changes outcomes. Gait symmetry and gait velocity are listed as secondary outcomes, including self-paced and fast-paced velocity. However, the primary outcome entry names baseline measurement using the Double Adjustable AFO, and the registry record does not report its observed mean, standard deviation, or a comparison estimate. The endpoint’s definition is therefore available, but its numerical results and precision are not reported in the registry record.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry record establishes the trial question and design, but it does not report the numerical primary outcome results. In particular, it gives no observed mean or standard deviation for the Six Minute Walk test, no estimated difference between device conditions, and no confidence interval or p-value for the primary comparison. The size, direction, and statistical precision of any primary outcome difference therefore cannot be assessed from the registry record.
The study enrolled 23 participants and is marked completed. Those details do not reveal how many participants contributed measurements to each outcome or whether every participant completed both device conditions. The registry record does not report participant flow, outcome-specific denominators, or the analysis population. It would be inappropriate to treat the enrollment figure as the number analyzed for every endpoint.
The design is randomized and crossover, with two possible sequences of practice. In general, a crossover design can compare measurements from the same participant under different conditions. Such comparisons must account for the paired structure of the observations. Period, order, or lingering effects can also matter in crossover studies; the registry record does not report whether these were evaluated or how they were handled in analysis. The design description alone does not establish that any particular model or adjustment was used.
The registry lists four outcome measures and 18 analyses. That does not identify which analysis was designated as primary, how the other analyses were organized, or whether any adjustment for multiple testing was applied. The statistical analysis plan and multiplicity approach are not reported in the registry record. As a general statistical point, considering multiple outcomes or analyses can increase the chance of at least one apparently notable result unless the analysis plan accounts for that structure. This general concern is not evidence that a specific error occurred in this study.
Without a reported effect estimate and its uncertainty, a reader cannot judge whether the data are compatible with a small or large difference, or with little discernible difference. Absence of reported results is not evidence that the devices performed equally, and it is not evidence that one performed better. No conclusion about the comparative gait outcomes can be drawn from the available registry results.
9. Statistical Methods Explained
What does a randomized crossover design mean?
In general, a crossover trial assigns participants to sequences of conditions, so that a participant may receive or use more than one condition during the study. Here, the registry describes two sequence orders for practicing with the AFOs, with one week assigned to each device. Random allocation concerns assignment to those sequences; it does not mean that participants or assessors were masked. The registry explicitly lists masking as none.
A crossover design can make within-participant comparisons possible. In general, each participant can serve as their own reference, which can reduce the influence of stable differences between participants. That advantage depends on appropriate analysis of the repeated measurements. The registry record does not report the statistical model, whether participant-level pairing was used, or whether the analysis accounted for sequence or period. It also does not report whether potential carryover effects were assessed. These are methodological questions raised by the design, not claims about what the investigators did.
How should a mean and standard deviation be read?
The primary outcome is a continuous measure in meters, and the registry describes its summary as a mean with standard deviation. In general, the mean gives the arithmetic average of observed values, while the standard deviation describes how spread out those values are around the mean. The standard deviation is not the uncertainty interval for the mean, and it does not directly measure the precision of a comparison between devices. To interpret a difference, readers would generally need an estimated contrast and an uncertainty measure such as a confidence interval. None is reported for the primary outcome in the registry record.
The primary outcome entry names baseline measurement using the Double Adjustable AFO. The study purpose also describes measurements with both devices and assessment of practice effects. These descriptions do not supply an analysis specification or numerical results. The distinction matters: a descriptive summary under one condition is not the same as an estimated randomized comparison between conditions, and the registry record does not state how the primary question was tested.
What would a confidence interval contribute?
In general, a confidence interval expresses the precision of an estimated quantity under the assumptions of the analysis. A narrower interval indicates greater precision than a wider interval, while the values included indicate which effect sizes remain compatible with the data and method. A confidence interval is not a guarantee that the true effect lies within its limits. Because no primary effect estimate or confidence interval is reported in the registry record, the precision of the device comparison cannot be evaluated.
What do significance tests and multiplicity mean?
In general, a p-value describes how incompatible the observed data are with a specified null model, assuming that model and the analysis assumptions are appropriate. It does not measure the probability that a treatment is effective, nor does it quantify the size or practical importance of an effect. The registry record does not report a primary-outcome p-value or the statistical test used.
The record lists four outcome measures and 18 analyses. When several outcomes, time points, or analyses are considered, the interpretation of individual p-values depends on which comparisons were planned and whether multiplicity was addressed. The analysis plan, prespecification details, and any multiplicity adjustment are not reported in the registry record. The count of analyses alone does not indicate which results, if any, were considered confirmatory.
How should planning illustrations be understood?
In general, sample-size calculations describe how many participants might be needed under specified assumptions; they do not describe the effect actually observed or establish the precision of a completed trial. The registry's planning description specifies a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation, with the effect to detect expressed as a fraction of the observed effect. It identifies the calculations as planning illustrations rather than the trial's own design justification. Any such sample-size figure is a planning illustration, not observed power. The registry record does not report a sample-size justification for the original study, and no numerical planning result is stated in the record.
The outcome type is continuous, and the record identifies mean and standard deviation summaries. It does not report whether the analysis used a paired model, an adjusted model, or another method. Those details cannot be inferred from the outcome format or crossover design.
10. Multiplicity, Missing Data and Analysis Populations
The registry record lists four outcome measures and 18 analyses, but does not report a statistical analysis plan specifying which analyses were primary, secondary, or exploratory. It does not state whether the multiplicity of outcomes and analyses was addressed, nor does it describe a correction or other strategy for interpreting multiple tests. The number of listed analyses alone does not show how many comparisons were planned or how their results were interpreted.
Missing-data handling is also not reported in the registry record. There is no stated method for incomplete assessments, missed visits, withdrawal, or unavailable outcome measurements. The record does not report the number of participants contributing data to each outcome or whether analyses included all randomized participants, only those completing both periods, or another group. Enrollment of 23 should therefore not be treated as an outcome-specific analysis denominator.
Analysis populations are not defined in the registry record. In general, this information helps readers understand which participants contributed to an estimate and whether exclusions after randomization may affect interpretation. For a crossover design, completion of both device conditions and treatment of incomplete sequences can also matter. The record does not describe these details.
These omissions limit assessment of the reported analysis because no primary outcome results are reported either. It is not possible to determine how missing observations, multiple comparisons, or analysis-set choices affected the estimates. The absence of those details is a reporting limitation; it does not establish that any particular method was or was not used.
11. Safety Results
The registry reports serious adverse events as affected participants divided by participants at risk.
| Arm | Participants with serious adverse events | Participants at risk | Percentage |
|---|---|---|---|
| PLS AFO | 1 | 23 | 4.3% |
| DA AFO | 0 | 23 | 0.0% |
Deaths
| Arm | Deaths (participants affected of at risk) |
|---|---|
| PLS AFO | 0 of 23 |
| DA AFO | 0 of 23 |
Other (non-serious) adverse events
Participants with at least one non-serious event at or above the registry's 1% reporting threshold.
| Arm | Participants affected of at risk |
|---|---|
| PLS AFO | 1 of 23 |
| DA AFO | 0 of 23 |
Most frequent serious adverse event terms
| Event term | Organ system | PLS AFO | DA AFO |
|---|---|---|---|
| Stroke | Nervous system disorders | 1 of 23 | 0 of 23 |
Most frequent non-serious adverse event terms
| Event term | Organ system | PLS AFO | DA AFO |
|---|---|---|---|
| Fatigue | Musculoskeletal and connective tissue disorders | 1 of 23 | 0 of 23 |
Serious events with the highest arm-level rate: stroke (4.3%).
The registry lists serious adverse event figures separately for the two AFO groups. For the Posterior Leaf Spring AFO, 23 participants are listed as at risk and 1 as affected by a serious adverse event. For the Double Adjustable AFO, 23 are listed as at risk and 0 as affected. The registry lists 0 deaths in each group.
The record also lists 1 other adverse event among 23 at risk for the Posterior Leaf Spring AFO, and 0 among 23 at risk for the Double Adjustable AFO. Among the serious adverse event terms, Stroke is listed with 4.3%. These are the registry's posted safety figures; the record does not provide additional event descriptions or analysis details that would establish why events occurred or whether they were related to an AFO.
In general, adverse event counts describe events reported during the study and do not, by themselves, establish causation. The crossover design means participants could use both devices in sequence, but the registry record does not explain how the safety denominators were assigned across exposure periods or how repeated exposure was handled. The figures should therefore be read as reported, without inferring a comparative safety effect from them.
12. What the Result Does, and Does Not, Mean
The record describes a randomized crossover study of two AFO types for people with subacute stroke and foot drop. It identifies gait endurance measured by the Six Minute Walk test as the primary outcome, with the primary outcome entry specifying baseline measurement using the Double Adjustable AFO. It also describes gait symmetry and gait velocity as secondary outcomes and sets out two possible practice sequences.
What the record does not provide is the numerical result needed to answer the comparative question. There is no reported primary-outcome mean, standard deviation, effect estimate, confidence interval, or p-value. The direction and size of any difference between devices, and the precision with which it was estimated, are therefore unknown from the registry record.
This absence must not be interpreted as evidence that the devices had equal outcomes, nor as evidence that one device performed better. It also does not establish that an effect was absent or clinically unimportant. Those judgments require results and an analysis that can be evaluated, neither of which is reported for the primary outcome in the registry record.
The design may support within-participant comparisons in principle, but a design description is not a substitute for knowing the analysis model, handling of sequence or period, outcome completeness, and analysis population. These details are not reported. Likewise, the adverse event counts are descriptive registry figures and do not establish causality or a comparative safety conclusion.
The sound interpretation is limited: the study was completed with 23 enrolled participants and compared two AFO conditions using a randomized crossover arrangement, but the registry record does not report enough outcome or analysis information to quantify the gait-endurance findings.
13. Why This Trial Matters Statistically
This trial raises a useful statistical example because the design and clinical question are described, while the primary outcome results and analysis details are not reported in the registry record. That distinction is central to evidence interpretation: knowing how a study was organized does not reveal what the measured outcomes were or how precisely a comparison was estimated.
The crossover structure also makes the example relevant to repeated-measures reasoning. In general, observations from the same participant under different conditions are related, so analyses should reflect that dependence. Sequence and period can matter when conditions are used over time. The registry describes randomized practice order and two one-week practice periods, but it does not report how such features were treated analytically. The design invites these questions without answering them.
The listed continuous primary outcome provides another basic teaching point. A mean and standard deviation describe a distribution of measurements, but they are not a complete account of a treatment comparison. An effect estimate and its uncertainty are needed to assess magnitude and precision. The registry record does not report those primary outcome statistics.
Finally, the registry lists multiple outcomes and analyses, but does not describe a multiplicity strategy or analysis plan. This illustrates why a count of analyses cannot replace prespecification and clear reporting. Taken together, the record permits an outline of the study question, design, endpoint, and safety counts, but not a numerical conclusion about comparative gait outcomes. That boundary is itself statistically important: conclusions should follow the reported evidence rather than fill gaps with assumptions.
14. 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 primary limitation for interpreting results is that no numerical primary outcome results are reported in the registry record. The record defines gait endurance as a mean in meters measured with the Six Minute Walk test, but gives no observed values or comparison estimate. Thus the magnitude, direction, and precision of the primary result cannot be assessed.
Further limitations arise from missing reporting on the analysis. The statistical model, handling of the crossover sequence and periods, analysis populations, and treatment of missing outcome data are not reported in the registry record. The number of participants contributing to each measure is also not reported. Enrollment of 23 does not establish the denominator for any particular analysis.
The registry describes four outcome measures and 18 analyses, but does not report which comparisons were prespecified or whether multiplicity was addressed. It also does not report a sample-size justification for the original trial. A planning description refers to illustrations based on an observed effect, but those illustrations do not provide an observed primary outcome result or a substitute for the trial's own design rationale.
The study is listed as unmasked, and its crossover design involves two device conditions and two possible practice sequences. The registry record does not report whether outcome assessors were masked, whether order effects were examined, or how incomplete participation in either period was handled. These are limits on what can be evaluated from the registry record, not evidence that the study necessarily handled them improperly.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Effects of Two Different Types of Ankle Foot Orthoses on Gait Outcomes in Patients With Subacute Stroke. — NCT02693834.
- Registry record last updated 2020-02-28; status last verified 2019-11.
- Results first posted 2020-02-28.
- 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.
Continue through the Clinical Biostats statistical pathway
Use this trial's endpoint as a starting point for deeper study of effect measures, confidence intervals, and sample-size planning.
18. Record Summary
NCT02693834 is a completed randomized crossover study sponsored by Texas Woman's University. The registry lists 23 enrolled participants, no masking, a start date of 2016-01, and primary completion in 2018-04. The phase is listed as NA.
The study compared a Posterior Leaf Spring AFO with a Double Adjustable AFO in people with subacute stroke and foot drop. Its primary outcome was gait endurance, measured with the Six Minute Walk test in meters; gait symmetry and gait velocity were listed as secondary outcomes. The registry describes one-week practice periods in randomized sequence.
The registry record does not report numerical primary outcome findings, a primary comparison estimate, or the statistical analysis plan. It lists serious and other adverse event counts by AFO group, including 0 deaths in each group. The available record supports description of the study design and endpoints but not a conclusion about comparative gait outcomes.