Clinical Trial Comparing C-Brace to Knee Ankle Foot Orthosis (KAFO)/Stance Control Orthosis (SCO): Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Clinical Trial Comparing C-Brace to Knee Ankle Foot Orthosis (KAFO)/Stance Control Orthosis (SCO) (NCT03906656), a randomized na study. The primary outcome is Primary Efficacy: Berg Balance Scale (BBS).

2. Clinical Question

In practical statistical terms, the comparison asks whether BBS scores differed across the recorded assessment conditions and, especially, whether final scores differed between use of C-Brace and conventional KAFO/SCO. The BBS measures static and dynamic balance; higher scores indicate better balance. The registry describes a randomized, open-label crossover trial, but does not report the allocation sequence, period-specific analysis details, or how the crossover structure was incorporated into the sponsor’s model. Those details matter when interpreting a comparison of final values because observations from the same participant across periods are related. The posted summary statistics alone do not show that within-participant relationship.

3. Trial Design

The registry describes a prospective, international, multicenter, open-label, randomized controlled crossover trial. It lists enrollment of 149 and a completed status. The listed start date is 2019-03-11, and the primary completion date is 2022-08-23. The sponsor is Otto Bock Healthcare Products GmbH. The trial compared a newly fitted C-Brace microprocessor-controlled stance and swing orthosis with existing KAFO or SCO use.

Each described treatment period involved home use for 3 months. Participants were assigned to a crossover comparison, meaning they had periods using both the C-Brace and conventional orthosis approach. The registry identifies no masking. The primary outcome timeframe includes baseline and assessments 3 months after each home-use period. This allows outcome recording across the two treatment conditions, but the registry record does not report the sequence allocation details, any washout interval, or how period and sequence effects were handled in the analysis.

The primary efficacy outcome was the Berg Balance Scale, analyzed as a continuous score with means and standard deviations. The primary population is described as intention to treat. The registry also lists secondary outcomes including balance confidence, gait, walking distance, stair performance, falling, fear of falling, and reintegration to normal living. It records 15 outcome measures and 20 analyses. The number of participants in the posted outcome summaries is not constant: the primary summaries list 102 at baseline, 86 for KAFO, and 77 for C-Brace. The registry record does not explain the changing denominators or specify how missing outcome measurements were handled.

Because the trial is a crossover, the interpretation of comparative results depends in part on whether the analysis accounts for the pairing of measurements within participants and for possible period effects. The registry reports a two-sided t-test for the primary final-value comparison, but does not report further details of that model or its assumptions. The posted group summaries can be read descriptively, while the sponsor’s reported analysis is the record’s stated inferential comparison.

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: 149 subjects were enrolled, and 41 failed screening (27 due to BBS score above 44, 11 failed the C-Brace trial tool assessment, 1 had a contraindication for the C-Brace, 1 had a history of vertigo, and 1 was geographically inaccessible). In addition, another 6 subjects dropped out after screening, but prior to randomization. Reasons for these early dropouts were lack of time (2) and personal problems (1) resulting in 102 patients randomized.

Fitting/Assessment Prior to Home Use 1

Reasons for not completing this period:

Home Use 1 (3 Months)

Reasons for not completing this period:

Fitting/Assessment Prior to Home Use 2

Reasons for not completing this period:

Home Use 2 (3 Months)

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: Intention to Treat Analysis

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: Intention to Treat Group

6. Primary Endpoint

The registry lists the primary outcome as Primary Efficacy: Berg Balance Scale (BBS), measured over Baseline, 3 months after initial home use period, and 3 months after cross-over home use period.

The primary endpoint is the Berg Balance Scale (BBS), a 14-item measure designed to assess static and dynamic balance in adults in a clinical setting. The score ranges from 0 to 56, with higher scores indicating better balance. According to the registry description, points may be deducted when time or distance requirements are not met, when performance requires supervision, or when assistance from a support person or examiner is needed.

The BBS is used as a standardized continuous measure: each participant’s performance is represented by a score, and groups or conditions can be described by their mean and standard deviation. The registry records assessments at baseline, 3 months after the initial home-use period, and 3 months after the crossover home-use period. This makes the measure relevant to the stated question about balance during use of the two orthosis approaches.

A mean summarizes the central level of the scores, while the standard deviation describes how dispersed individual scores are around that mean. Neither summary by itself captures every feature of the score distribution or the pattern of change for each participant. In a crossover trial, within-participant changes can be particularly informative, but the registry record does not report participant-level changes or full details of the sponsor’s statistical model. The group summaries therefore describe the recorded scores, while the sponsor’s reported final-value comparison is the registry’s own inferential result.

7. Results Posted in the Registry

• KAFO: mean 37.30 versus 33.60 on control; difference 3.70 (95% CI 0.62 to 6.78), standardized effect d = 0.34; z-test p = 0.019.
• C-Brace: mean 42.00 versus 33.60 on control; difference 8.40 (95% CI 5.45 to 11.35), standardized effect d = 0.82; z-test p = <0.001.

8. Secondary Efficacy Endpoints

The registry also posts results for secondary outcomes. For each outcome below, the endpoint type, the test applied to the posted summary statistics, the result and its interpretation are given in turn. Secondary endpoints are usually not adjusted for multiple testing, so they support rather than confirm the primary finding.

Activity-specific Balance Confidence (ABC) Scale

• Endpoint type: Continuous: a mean value per participant, compared as a difference in means.
• Test: Unadjusted two-sample z-test for the difference in means, using the posted standard deviations.
• Result:
  • KAFO: mean 51.00 versus 53.10 on control; difference -2.10 (95% CI -7.63 to 3.43), standardized effect d = -0.11; z-test p = 0.457.
  • C-Brace: mean 62.30 versus 53.10 on control; difference 9.20 (95% CI 3.39 to 15.01), standardized effect d = 0.48; z-test p = 0.002.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between KAFO and the control. The interval gives the range of effects that remain compatible with the data.
  • The 95% confidence interval excludes no difference, so the mean is statistically higher for C-Brace than for the control. This is an unadjusted, secondary comparison, so it is suggestive rather than confirmatory.

Dynamic Gait Index (DGI)

• Endpoint type: Continuous: a mean value per participant, compared as a difference in means.
• Test: Unadjusted two-sample z-test for the difference in means, using the posted standard deviations.
• Result:
  • KAFO: mean 13.40 versus 12.30 on control; difference 1.10 (95% CI 0.16 to 2.04), standardized effect d = 0.34; z-test p = 0.022.
  • C-Brace: mean 15.70 versus 12.30 on control; difference 3.40 (95% CI 2.42 to 4.38), standardized effect d = 1.03; z-test p = <0.001.
• Interpretation:
  • The 95% confidence interval excludes no difference, so the mean is statistically higher for KAFO than for the control. This is an unadjusted, secondary comparison, so it is suggestive rather than confirmatory.
  • The 95% confidence interval excludes no difference, so the mean is statistically higher for C-Brace than for the control. This is an unadjusted, secondary comparison, so it is suggestive rather than confirmatory.

6-minute Walk Test

• Endpoint type: Continuous: a mean value per participant, compared as a difference in means.
• Test: Unadjusted two-sample z-test for the difference in means, using the posted standard deviations.
• Result:
  • KAFO: mean 213.70 versus 204.90 on control; difference 8.80 (95% CI -13.56 to 31.16), standardized effect d = 0.11; z-test p = 0.441.
  • C-Brace: mean 226.00 versus 204.90 on control; difference 21.10 (95% CI -2.61 to 44.81), standardized effect d = 0.27; z-test p = 0.081.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between KAFO and the control. The interval gives the range of effects that remain compatible with the data.
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between C-Brace and the control. The interval gives the range of effects that remain compatible with the data.

The detailed secondary results cover measures of balance confidence, gait, and walking distance. Taken together, they do not show one uniform pattern across all functional outcomes. Some sponsor-reported comparisons are labelled as superiority, while the sponsor’s reported comparison for the 6-minute Walk Test is not. This broad pattern complements the primary BBS result by showing that secondary measures do not all provide the same statistical signal.

Secondary endpoints assess related but distinct constructs. Confidence in balance, performance on a gait index, and distance walked during a timed test are not interchangeable measures. Differences in outcome content, measurement variability, and the number of participants contributing data can produce differing estimates. The secondary outcomes can therefore add context to the balance finding, but they do not independently confirm the same effect simply because they concern mobility or function.

The registry lists additional outcomes, including stair performance, frequency and fear of falling, and reintegration to normal living. The record describes 14 posted secondary outcomes, but the detailed results available for interpretation do not establish a complete inferential picture for every listed measure. Missing or unreported outcome detail should not be taken as evidence of either a positive or a null result.

Unadjusted secondary p-values carry less weight when many outcomes and analyses are considered. If no multiplicity adjustment is used, testing many hypotheses can increase the chance that at least one result appears statistically notable by chance. The registry record does not report whether a multiplicity strategy was prespecified or applied. Secondary findings are therefore best treated as supportive or exploratory context, with emphasis on the size and precision of estimates where reported rather than on isolated significance labels.

The BBS remains the designated primary efficacy measure in the registry. Secondary results can broaden understanding of the outcome pattern but cannot replace the primary analysis or resolve limitations in the primary analysis details, including the absence of a reported confidence interval for the sponsor’s direct comparison and the limited description of crossover modeling.

Secondary outcomes registered for this trial, for reference (only those above were recalculated):

• Activity-specific Balance Confidence (ABC) Scale
• Dynamic Gait Index (DGI)
• 6-minute Walk Test
• Stair Assessment Index (SAI) - Down
• Frequency of Falling
• Fear of Falling
• Probability of Falling More Than Once When Using C-Brace Compared to KAFO/SCO
• Reintegration to Normal Living (RNL) Index Questionnaire

9. Statistical Interpretation

10. Statistical Methods Explained

Continuous outcomes such as the BBS are commonly summarized by a mean and standard deviation. The mean gives the arithmetic average score among participants contributing data to that summary. The standard deviation describes variability among individual scores: a larger standard deviation indicates more spread around the mean. These summaries are useful for describing groups, but they do not show the full score distribution, each participant’s change, or the relationship between repeated measurements from the same person.

What does a mean difference describe?

A mean difference expresses the separation between two group or condition means, in the outcome’s original units. For the BBS, that unit is score points. A positive difference in the posted recalculations means the named condition’s mean is higher than the baseline mean. A mean difference is an estimate, not a guarantee that every participant experienced a change of that size. It also does not, on its own, show whether a difference is important to patients; the registry record does not report a threshold for clinical importance.

How should a confidence interval be read?

A confidence interval gives a range of values compatible with the estimate under the statistical method and assumptions used. It conveys uncertainty as well as direction and scale. A narrower interval indicates greater precision than a wider interval, all else being equal. The recalculated BBS intervals are simple, unadjusted intervals based on posted summary statistics. They do not represent an interval from the sponsor’s reported crossover analysis, for which the registry does not provide confidence limits.

What does a p-value tell the reader?

A p-value describes how incompatible the observed data are with a specified null hypothesis under the statistical test’s assumptions. A smaller p-value indicates greater incompatibility with that null model; it does not measure the probability that the null hypothesis is true, the size of an effect, or the probability of benefit for an individual. The registry reports two-sided t-tests for the primary final-value analyses. The simple recalculations also report unadjusted p-values. The registry record does not report a complete statistical analysis plan or details of all model assumptions.

The distinction between the sponsor’s analysis and the simple recalculations is important. The recalculations use posted group-level means, standard deviations, and sample sizes to form unadjusted comparisons. They do not use participant-level paired changes and cannot recover the covariance between measurements on the same participant. In a crossover design, that covariance can influence the uncertainty of a within-person treatment comparison. A crossover analysis may also need to address treatment period or sequence effects. The registry does not report whether or how those considerations were incorporated into the sponsor’s analysis. Since a discrepancy is recorded, the sponsor’s own analysis takes precedence as the trial’s reported inferential analysis.

The primary population is identified as intention to treat. In general, an intention-to-treat analysis seeks to retain participants in the groups to which they were randomized, regardless of later treatment use. The registry record does not provide the detailed rules used to implement this population, explain the reduced numbers in outcome summaries, or describe imputation or other missing-data procedures. Therefore, the label alone does not settle how missing measurements or incomplete crossover periods were handled.

The trial is described as open-label and unmasked. General statistical reasoning recognizes that awareness of treatment assignment can affect subjective reporting, participant behavior, or assessment, especially for outcomes involving confidence or perceived fear. The BBS is a structured assessment, but the registry does not report assessor masking or other safeguards. This is a potential interpretive consideration, not evidence that measurement was biased.

Several outcomes and analyses are registered. When many outcomes or contrasts are tested, the chance of obtaining one or more small p-values by chance can increase if all tests are treated as equally confirmatory. Multiplicity methods can control that risk, but the registry record does not report a prespecified adjustment strategy. Accordingly, the results across secondary measures should be considered in the context of the number of analyses and their exploratory status rather than interpreted one at a time as definitive evidence.

Finally, the planning illustrations use a normal approximation and assumed equal allocation between two arms, with a two-sided significance level of 0.05. They use an effect equal to a stated fraction of the observed effect. Those are planning assumptions for the illustrations, not documented assumptions from the trial’s original design. The original sample-size justification and its assumptions are not reported in the registry record.

11. Confidence Intervals and Precision

The recalculated BBS comparison of KAFO with baseline has a mean difference of 3.7, with a 95% confidence interval from 0.621 to 6.779. The corresponding C-Brace comparison with baseline has a mean difference of 8.4, with a 95% confidence interval from 5.452 to 11.35. These intervals give a sense of precision for the simple unadjusted comparisons based on the posted summary statistics. They are not confidence intervals for the sponsor’s direct final-value comparison between C-Brace and KAFO.

The sponsor reports a direct final-value mean difference of 3.5 between C-Brace and KAFO, with p < 0.001, but does not report a confidence interval for that contrast. A p-value alone does not show the range of effect sizes compatible with the data, so precision for the sponsor’s direct comparison cannot be assessed from a reported interval. The discrepancy between the direct sponsor analysis and the simple recalculations also means the recalculated intervals should not be used to fill that gap.

In general, a confidence interval’s width reflects both the amount of information and the variability in the data, together with the method used to calculate the interval. Greater precision does not establish clinical importance, and an interval’s relationship to a null value is not the only consideration in interpreting a result. The registry does not report a BBS threshold for clinical importance, and the summary statistics do not convey participant-level response patterns.

Precision is also affected by the number of participants contributing measurements. The primary outcome summaries have different sample sizes across baseline, KAFO, and C-Brace. The registry record does not explain the changing numbers or report missing-data handling. For a crossover comparison, the uncertainty depends in part on within-participant information that cannot be reconstructed from separate means and standard deviations. The posted intervals should therefore be understood as limited, unadjusted summaries rather than as a complete account of uncertainty in the trial’s crossover estimate.

12. Planning a Similar Trial: Sample Size

This is a planning illustration, not a re-evaluation of the original trial. It asks: if a new study wanted to detect a difference like the one observed, or a smaller one, how large would it need to be? It is deliberately not “observed power” of the finished trial, which is not a meaningful quantity.

The planning figures are expressed as participants per arm for the continuous-outcome comparisons. They are not total event counts. The registry’s planning assumptions are a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. The effect to be detected is set to the stated fraction of the observed effect. The trial’s original sample-size justification and original design assumptions are not reported in the registry record.

The 80% power column gives the illustrative number of participants per arm that would yield an 80% chance of detecting the specified effect under those assumptions, if that effect and the assumptions were correct. The 90% power column uses a higher target chance of detecting that same specified effect, so it generally calls for more participants per arm. These figures describe hypothetical planning scenarios; they are not estimates of the probability that this completed trial detected an effect.

Each planning row uses a different fraction of the observed effect. Planning for 75% of the observed effect or 50% of the observed effect assumes a smaller target effect than planning for 100% of the observed effect. Smaller effects are harder to distinguish from random variation and therefore require more participants under the same design assumptions. The figures are illustrations based on the observed estimate, not a claim that the observed effect is the true effect or that the trial was designed around it.

This is not observed power. Observed power is not a useful substitute for interpreting the estimate, its uncertainty, and the design; the planning calculations instead show hypothetical sample-size requirements under explicit assumptions. They also do not account for crossover features unless those are part of the stated calculation assumptions, which they are not.

13. How the Sample Size Is Derived

Power is the probability that a study of a given size rejects the null hypothesis when a specific true effect exists. It depends on four things: the effect to detect, the variability of the outcome, the significance level (here a two-sided α of 0.05, so z_1−α/2 = 1.960) and the desired power (z_1−β = 0.842 for 80% and 1.282 for 90%).

Formula

n is the number of participants in each arm, Δ is the difference in means to detect and σ is the common standard deviation.

Worked calculation for this trial

1. Observed difference Δ = 3.700; pooled standard deviation σ = 10.774.
2. n = 2 × (1.96 + 0.842)² × 10.774² / 3.700² = 133.1, rounded up to 134 participants per arm for 80% power.

The smaller-effect rows in the table above repeat the same calculation with the effect multiplied by 0.75 and 0.5 (for ratios, applied to the logarithm of the ratio).

R code

alpha <- 0.05
z_a   <- qnorm(1 - alpha / 2)          # two-sided
delta <- 3.7                      # observed difference in means
sigma <- 10.7743846966496                     # pooled standard deviation
n_per_arm <- function(power, frac = 1) {
  ceiling(round(2 * (z_a + qnorm(power))^2 * sigma^2 / (delta * frac)^2, 6))
}
for (f in c(1, 0.75, 0.5))
  cat(sprintf("%3.0f%% of observed effect: n per arm = %s (80%% power), %s (90%% power)\n", 100 * f,
              format(n_per_arm(0.80, f), big.mark = ","), format(n_per_arm(0.90, f), big.mark = ",")))

# Check against R's built-in function (t-based, so very slightly larger)
cat("power.t.test:", round(power.t.test(delta = delta, sd = sigma, power = 0.80)$n, 1), "\n")

# Simulation: exact two-sample t-test using simulated means and variances
set.seed(3906656)
n    <- n_per_arm(0.80)
reps <- 20000
m_diff <- rnorm(reps, delta, sigma * sqrt(2 / n))             # difference in sample means
s2     <- sigma^2 * rchisq(reps, 2 * (n - 1)) / (2 * (n - 1))   # pooled sample variance
tstat  <- m_diff / sqrt(s2 * 2 / n)
cat(sprintf("Simulated power at n = %s per arm: %.3f (%d replicates)\n", format(n, big.mark = ","), mean(abs(tstat) > qt(0.975, 2 * (n - 1))), reps))

Output from running the code

100% of observed effect: n per arm = 134 (80% power), 179 (90% power)
 75% of observed effect: n per arm = 237 (80% power), 317 (90% power)
 50% of observed effect: n per arm = 533 (80% power), 713 (90% power)
power.t.test: 134.1 
Simulated power at n = 134 per arm: 0.804 (20000 replicates)

The simulation draws many sets of group means and variances at the planned sample size and counts how often the two-sample t-test rejects the null. It should land close to the target power; at very small required sample sizes it can fall below it, because the normal approximation is rough there.

14. Analyses Reported by the Sponsor

The registry reports sponsor analyses using two-sided t-tests and describes the primary result as a mean difference in final values. For the C-Brace versus KAFO comparison, the reported mean difference is 3.5 with p < 0.001. It also reports final-value comparisons against baseline: 6.8 for C-Brace and 3.3 for KAFO, each with p < 0.001. Confidence intervals are not reported for these sponsor comparisons.

The simple recalculations use the posted means, standard deviations, and sample sizes to compare each condition with baseline. They do not reproduce the sponsor’s direct C-Brace-versus-KAFO final-value contrast. The registry marks a discrepancy between the recalculations and reported analyses. This can arise because the calculations answer different questions or use different information and methods; the registry does not provide enough detail to identify the exact reason.

Accordingly, the sponsor’s own analysis takes precedence when describing the trial’s reported inferential result. The recalculated estimates and intervals can be read as unadjusted descriptions derived from the group summaries, not as corrections to or replacements for the sponsor’s analysis. The registry does not report sufficient model detail to independently assess how the sponsor accounted for the crossover structure.

15. Multiplicity, Missing Data and Analysis Populations

The registry lists multiple outcomes and analyses. When many statistical tests are conducted, the chance of finding one or more apparently notable results by chance can rise if each is interpreted as a separate confirmatory test. A multiplicity plan may specify which endpoint is primary, how secondary endpoints are ordered, or how significance thresholds are adjusted. The registry identifies the BBS as the primary efficacy outcome, but a detailed multiplicity procedure is not reported in the registry record.

The registry reports unadjusted p-values for simple recalculations and sponsor p-values for selected analyses. It does not state whether those values were adjusted for testing multiple outcomes, contrasts, or time points. This limits how strongly the secondary findings can be treated as confirmatory. The primary outcome designation helps distinguish the principal question, but it does not by itself describe the complete testing hierarchy or control of error across all analyses.

The primary population is described as intention to treat. However, the registry record does not report the detailed analysis population rules, the number randomized to each sequence, or how participants with incomplete follow-up or incomplete crossover periods were included. Outcome-specific sample sizes vary, and the record does not explain those differences. Missing-data methods, including whether any imputation was used, are not reported in the registry record.

These omissions matter because missing measurements can affect both the estimate and its precision, particularly if the availability of data is related to participant characteristics or outcomes. In a crossover trial, incomplete periods can also affect which within-person comparisons are available. The posted summaries do not allow those issues to be evaluated fully.

The registry reports a two-sided t-test for the sponsor’s final-value analyses, but does not provide the complete statistical analysis plan, detailed model specification, or treatment of period and sequence effects. It also does not report a detailed justification for the primary sample size. These are limits on independent appraisal, not evidence that a particular method was or was not used.

16. 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.

Most frequent serious adverse event terms

Most frequent non-serious adverse event terms

Serious events with the highest arm-level rate: prostate cancer (2.2%), intestinal haemorrhage (1.1%), chest pain (1.1%), foot fracture (1.1%), syncope (1.1%).

The registry reports serious adverse events affecting 10 of 102 participants at risk in the KAFO/SCO group and 6 of 88 participants at risk in the C-Brace group. It reports other, non-serious adverse events affecting 66 of 102 participants at risk in the KAFO/SCO group and 57 of 88 participants at risk in the C-Brace group. Deaths are reported as 0 for KAFO/SCO and 2 for C-Brace.

These are counts of affected participants and participants at risk as recorded by the registry; they are not rates calculated for a common follow-up duration. The registry record does not explain the differing numbers at risk, provide detailed exposure time, or state whether each event was considered related to an orthosis. It therefore does not support a causal interpretation of differences in these counts.

The listed serious-event terms include Prostate cancer at 2.2%, and Intestinal haemorrhage, Chest Pain, Foot fracture, Syncope, and Deep Vein Thrombosis at 1.1% each. Those event terms provide a description of reported serious events, not a complete account of their clinical context or attribution. The figures should be interpreted as registry safety reporting rather than as proof that an intervention caused or prevented an event.

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

The results describe recorded balance scores and other functional measures in a randomized, open-label crossover trial comparing home use of C-Brace with existing KAFO or SCO use. The BBS means are higher in the C-Brace condition than at baseline and higher than the KAFO mean in the posted summaries. The sponsor reports a statistically significant direct final-value comparison between C-Brace and KAFO. These statements describe the posted measurements and analysis; they are not medical advice or a guarantee of an individual response.

Statistical evidence and clinical importance are different questions. The registry reports the BBS scale range and direction, but does not report a threshold for a clinically important difference. A p-value does not indicate how meaningful a difference is to participants, and a mean difference does not show how many people improved, stayed unchanged, or worsened. Individual-level data and a clinical-importance threshold are not reported in the registry record.

The sponsor’s direct comparison is the trial’s reported inferential result, while the recalculated comparisons are unadjusted analyses of group summary statistics. The recorded discrepancy means those recalculations should not be substituted for the sponsor analysis. In addition, the registry does not provide the full crossover model, confidence interval for the sponsor’s direct comparison, or complete missing-data methods. These gaps restrict what can be concluded about precision and robustness.

The secondary outcomes offer a mixed pattern and should be considered exploratory in the absence of a reported multiplicity strategy. Safety counts likewise describe events recorded in the registry and do not establish cause. Generalization beyond the trial population is also limited by the registry information: the results concern the participants and treatment periods studied, and the record does not provide enough detail to assess how closely those participants represent other settings or populations.

Overall, the registry records a favorable direction in the BBS group means for C-Brace and a sponsor-reported difference in final values versus KAFO. It does not, on its own, establish the magnitude of clinical benefit, the reasons for the observed differences, or effects in other populations.

18. Why This Trial Matters Statistically

This trial is statistically interesting because its randomized crossover design can compare two orthosis approaches within participants, while also creating analysis requirements that are not visible in group means alone. Measurements from the same person are related. Appropriate estimation of a within-person contrast can use that relationship, whereas a simple comparison of separate group summaries cannot recover it. The registry reports a sponsor analysis but does not describe enough of its model to evaluate how crossover features were handled.

The record also illustrates why the exact contrast matters. A comparison of each treatment condition with baseline answers a different question from a direct C-Brace-versus-KAFO comparison. The simple recalculations use baseline as the reference, while the sponsor reports a direct final-value contrast as well as comparisons against baseline. Keeping those contrasts separate prevents an unadjusted descriptive calculation from being mistaken for the trial’s principal comparative analysis.

Precision and transparency are also central. The sponsor’s direct comparison has a p-value but no reported confidence interval, while the simple recalculations have intervals based on more limited summary information. The difference between those analyses underscores the value of reporting estimates with confidence intervals and describing the model, missing-data handling, and crossover assumptions in sufficient detail.

Finally, the registry lists multiple secondary measures with different patterns and varying numbers of participants. Their interpretation depends on attention to multiplicity and completeness of reporting. The study therefore provides a useful example of how design, analysis, endpoint choice, precision, and reporting detail jointly shape statistical interpretation.

19. 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.

Several limitations are specific to the information reported for this trial. The record describes a crossover design and 3-month home-use periods, but does not report the randomized sequence details, any washout interval, or how period and sequence effects were addressed. These details are important for understanding a direct within-participant treatment comparison.

The registry reports the sponsor’s primary analysis as a two-sided t-test of final values but does not give a full model specification. It does not report a confidence interval for the sponsor’s direct C-Brace-versus-KAFO estimate. The unadjusted recalculations have confidence intervals, but they use group summaries and do not reproduce a detailed crossover analysis. The discrepancy between the sponsor results and the recalculations further cautions against treating the latter as the trial’s definitive estimate.

Outcome sample sizes vary across baseline and treatment summaries. The record does not explain the changing denominators or report how missing data, incomplete treatment periods, or analysis population rules were handled beyond identifying the primary population as intention to treat. It also does not report an original sample-size justification or detailed multiplicity plan.

The trial was open-label, and masking is listed as none. The record does not state whether outcome assessors were masked. Several secondary outcomes involve confidence, fear, or reported events, and many analyses are listed; without a reported multiplicity strategy, secondary p-values need cautious interpretation. The registry also does not state a clinically important difference threshold for the BBS. These limitations concern the available reporting and the scope of interpretation; they do not establish that the methods were inadequate or that the findings are biased.

20. Related Tutorials

21. Related Statistical Calculators

22. Sources

• ClinicalTrials.gov: Clinical Trial Comparing C-Brace to Knee Ankle Foot Orthosis (KAFO)/Stance Control Orthosis (SCO) — NCT03906656.
• Registry record last updated 2024-09-19; status last verified 2024-04.
• Results first posted 2024-09-19.
• 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.

23. Record Summary

The registry describes a completed, randomized, open-label multinational crossover trial comparing 3 months of home use with a newly fitted C-Brace and 3 months of home use with an existing KAFO or SCO. Enrollment is listed as 149. The primary efficacy outcome is the Berg Balance Scale, assessed at baseline and after each home-use period.

The posted primary summaries show mean BBS scores of 33.6 at baseline, 37.3 for KAFO, and 42.0 for C-Brace. The sponsor reports a final-value mean difference of 3.5 for C-Brace versus KAFO, with p < 0.001. Simple unadjusted recalculations are distinct from that sponsor comparison, and the registry records a discrepancy; the sponsor’s analysis takes precedence for the reported inferential result.

Secondary results and safety counts provide additional context but have limitations, including unreported multiplicity and missing-data methods and limited detail about the crossover analysis. The registry record does not report a confidence interval for the sponsor’s direct primary comparison or a threshold for clinical importance.