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 Walking Aids in the Management of Knee Osteoarthritis (NCT00223795), a randomized na study. The primary outcome is Peak Vertical Force on Affected Limb.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT00223795 |
| Phase | NA |
| Condition | Obesity, Osteoarthritis |
| Allocation | Randomized |
| Design model | Crossover |
| Masking | None (open label) |
| Enrollment | 53 |
| Arms in the primary outcome | n/a |
| Lead sponsor | VA Office of Research and Development |
| Results posted | Yes |
2. Clinical Question
Population
The study concerned people with knee osteoarthritis and was framed around overweight or obese people with the condition. The registry record lists obesity and osteoarthritis as conditions and reports enrollment of 53 participants. It does not give further eligibility details or describe the characteristics of the enrolled participants in the endpoint record.
Intervention
The intervention was a single point cane. The study assessed gait with and without a cane, and its stated purpose included examining whether cane use could alter joint biomechanics and what factors influence acceptance of cane use. The registry record does not report a result on acceptance.
Comparator
The comparison involved gait without a cane and gait with a cane. The arm descriptions indicate that one group began without a cane and crossed over to cane use, while the other arm was assigned a single point cane. The endpoint description also says that participants in both arms were tested walking with and without a cane at baseline and at the end of the first intervention period.
Primary question
The primary endpoint was peak vertical force on the affected limb, measured during laboratory gait evaluations. The clinical question was whether walking with a single point cane was associated with a change in that force measure in this study population. Although the registry identifies the endpoint, it records zero analyses and gives no endpoint means, standard deviations, treatment contrast, confidence interval, or p-value. The size and precision of any difference therefore are not reported in the registry record.
3. Trial Design
This was a randomized, unmasked crossover study of a single point cane in people with knee osteoarthritis. The registry record reports enrollment of 53 participants and identifies the study as completed. The listed start was 2006-07, and primary completion was 2008-09. The sponsor was the VA Office of Research and Development. The phase is listed as not applicable.
The arm descriptions indicate two sequences: an intervention group without a cane for the first 8 weeks followed by crossover to cane use, and a group assigned to a single point cane. The primary endpoint description refers to baseline and the end of the first intervention period, specified as 2 months. At both assessments, laboratory gait evaluations included walking with and without a cane in both arms. The description also says the control arm was not given a cane to use at home during the 2-month intervention period.
A crossover design allows comparisons within a participant across conditions or periods, but the registry record does not describe the detailed schedule beyond the arm descriptions and first-period assessment. It does not report whether later-period endpoint results were analyzed, how sequence or period effects were handled, or whether a washout period was used. Masking is listed as none. The record does not report the randomization procedure, allocation concealment, adherence, or protocol deviations. These details should not be inferred from the general design label.
The registry lists one outcome measure and zero analyses. It gives no numerical endpoint results. Consequently, the design and measurement schedule can be described, but the outcome comparison cannot be reconstructed from the posted results.
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.
First Intervention - Eight Weeks
| Stage | Arm 1 - Control/Crossover | Arm 2 - Cane |
|---|---|---|
| STARTED | 26 | 27 |
| COMPLETED | 19 | 18 |
| NOT COMPLETED | 7 | 9 |
Reasons for not completing this period:
| Reason | Arm 1 - Control/Crossover | Arm 2 - Cane |
|---|---|---|
| Lost to Follow-up | 7 | 9 |
Second Intervention - All Use Canes 4 mo
| Stage | Arm 1 - Control/Crossover | Arm 2 - Cane |
|---|---|---|
| STARTED | 19 | 18 |
| COMPLETED | 18 | 17 |
| NOT COMPLETED | 1 | 1 |
Reasons for not completing this period:
| Reason | Arm 1 - Control/Crossover | Arm 2 - Cane |
|---|---|---|
| Lost to Follow-up | 1 | 1 |
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 | Baseline Characteristics All Subjects |
|---|---|---|
| Participants analysed | 53 | |
| Age, Categorical: <=18 years | Participants | 0 |
| Age, Categorical: Between 18 and 65 years | Participants | 45 |
| Age, Categorical: >=65 years | Participants | 8 |
| Age, Continuous | years | 59.6 (SD 7.6) |
| Sex: Female, Male: Female | Participants | 9 |
| Sex: Female, Male: Male | Participants | 44 |
| Region of Enrollment: United States | participants | 53 |
6. Primary Endpoint
The registry lists the primary outcome as Peak Vertical Force on Affected Limb, measured over Baseline and end of first intervention period (2 months).
| Element | Registry entry |
|---|---|
| Result type | Mean |
| Measure of spread | Standard Deviation |
| Unit | N/kg |
| Endpoint classification | Continuous Endpoint |
The primary endpoint, peak vertical force on the affected limb, is a continuous measure reported in N/kg. It represents the peak vertical ground reaction force recorded during walking. The registry describes measurement with an in-shoe dynamic pressure distribution system during laboratory gait evaluations. Measurements were taken at baseline and at the end of the first intervention period, described as 2 months, and the assessments included walking both with and without a cane.
As a biomechanical measure, peak vertical force can characterize how force is distributed through the affected limb during gait. It is relevant to the study’s stated question about whether cane use changes joint biomechanics. It is not itself a direct measure of pain, disability, or acceptance of cane use. The study summary names pain, disability, biomechanics, and acceptance as areas of interest, but the listed primary endpoint is the force measure.
The endpoint is identified as a mean with standard deviation, but no mean or standard deviation values are reported in the registry record. There is also no posted treatment contrast or uncertainty estimate. The endpoint’s definition and measurement method therefore describe what was assessed, not whether the measure changed or how large any change was.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry record identifies a randomized crossover study and a primary continuous endpoint, but it does not provide an analyzed result for that endpoint. It lists one outcome measure and zero analyses. No numerical means, standard deviations, within-participant changes, treatment contrasts, confidence intervals, or p-values are recorded. Thus, the direction, magnitude, and precision of an endpoint difference are not reported in the registry record.
The measurement schedule is described for baseline and the end of the first intervention period. Participants in both arms were assessed walking with and without a cane. That description establishes the measurement conditions, but it does not supply the values from those assessments or specify which contrast was used for a statistical conclusion. It would be inappropriate to treat the study’s design description as evidence of a particular change in peak vertical force.
The registry’s description of a crossover is relevant to interpretation because measurements from the same participant across conditions are generally related. A valid analysis may need to account for that dependence, as well as the timing and sequence of conditions. The record does not state how these features were handled. It also does not report whether the first-period endpoint alone or observations from multiple periods formed the analysis.
Planning illustrations based on an observed effect, when available, are not evidence that an effect was observed with a particular degree of certainty. Such planning quantities are not observed power. In this record, no endpoint effect estimate is reported, so the magnitude underlying any such illustration cannot be assessed from the registry results. The stated general assumptions for planning include a two-sided significance level of 0.05, equal allocation, and a normal approximation; these assumptions do not substitute for trial results or establish the study’s original design rationale.
The appropriate conclusion is limited: the trial was designed to assess gait biomechanics under cane and no-cane conditions, and its primary endpoint was peak vertical force on the affected limb. The posted results do not permit a conclusion about the size or statistical precision of any difference. The absence of a reported estimate is not evidence that the conditions were equivalent, nor does it establish that a difference was present.
9. Statistical Methods Explained
General: Statistical methods for a clinical trial link the study design, the outcome measurement, and the comparison of interest. The registry describes a randomized crossover design and a continuous primary endpoint summarized as a mean and standard deviation. It does not report the method used to analyze that endpoint. The explanations below describe general considerations, not methods confirmed to have been used in this study.
What does a continuous endpoint mean?
A continuous measure can take a range of numerical values rather than belonging to a small set of categories. Peak vertical force on the affected limb is recorded in N/kg. A mean describes the central level of such measurements, while a standard deviation describes how spread out participant measurements are around that mean. The registry identifies mean and standard deviation as the summary format, but gives neither value for the endpoint. Without those summaries, the observed level and variability cannot be reviewed.
How does crossover affect analysis?
General: In a crossover study, a participant can contribute measurements under more than one condition. Those observations are often correlated because they come from the same person. An analysis that accounts for within-participant pairing can use that structure; treating all observations as independent may fail to represent it. Period and sequence can also matter: outcomes may change over time, or the order of conditions may affect measurements. If effects from an earlier condition persist into a later period, carryover may complicate interpretation. The registry record does not report whether pairing, period, sequence, or carryover was addressed in the analysis, or whether a washout period was used.
The endpoint description specifies baseline and the end of the first intervention period and notes gait measurements with and without a cane in both arms. It does not provide the participant-level observations or say which comparison was used in an analysis. The general crossover considerations therefore explain what an analysis might need to address; they do not identify the actual analysis for this trial.
What does uncertainty communicate?
General: A confidence interval is a range of values compatible with the data under a specified statistical method and its assumptions. Its width communicates precision: a narrower interval indicates greater precision than a wider interval. A p-value summarizes how compatible the observed data are with a specified null hypothesis under the analysis assumptions. Neither quantity by itself describes clinical importance, and neither can be interpreted without an estimate and a clear comparison.
No confidence interval, p-value, or endpoint contrast is reported in the registry record. Statistical significance and precision therefore cannot be assessed from the posted results. A lack of a reported p-value is not a p-value above a threshold, and the absence of an estimate does not establish no difference.
Why do model assumptions matter?
General: Statistical models rely on assumptions about the outcome distribution, the relationship among observations, and the way variability is represented. A normal approximation may be reasonable in some settings but can be less reliable when its assumptions do not fit the data. Over-dispersion, in general, means that observed variability exceeds what a model expects; ignoring it can make uncertainty appear smaller than it is. This endpoint is continuous and is identified with a mean and standard deviation, but no distributional assessment or model details are reported. The registry’s stated normal approximation concerns planning illustrations, not a documented endpoint analysis.
How should planning illustrations be read?
General: Sample-size planning describes the number of participants that might be needed to detect a specified effect under chosen assumptions. The registry’s planning description refers to a two-sided significance level of 0.05, equal allocation, a normal approximation, and effects expressed as a stated fraction of an observed effect. It also distinguishes participants per arm for non-time-to-event outcomes. These are planning assumptions, not a record of the trial’s original sample-size justification. The original justification is not reported in the registry record.
Planning illustrations are not observed power and do not show whether the trial demonstrated an effect. Their interpretation depends on the effect value and other inputs, and the endpoint effect itself is not reported in the registry results. The registry record does not establish an interim analysis plan, a prespecified statistical model, or the analysis actually applied.
10. Multiplicity, Missing Data and Analysis Populations
The registry record lists one outcome measure and zero analyses. It does not report a multiplicity adjustment, a hierarchy of outcomes, or a plan for handling multiple comparisons. The endpoint description includes gait measurements in two walking conditions and at baseline and the end of the first intervention period, but the record does not specify which contrasts were prespecified or analyzed. The presence of several measurement conditions does not by itself establish how many statistical tests were performed.
Missing-data information is not reported in the registry record. There are no endpoint counts identifying how many participants contributed measurements at each assessment or condition, and no account of missing values, exclusions, or imputation is given. The registry record also does not describe whether the analysis followed an intention-to-treat, per-protocol, or other population definition. These omissions limit assessment of potential bias from incomplete follow-up or analysis exclusions.
The registry’s stated planning assumptions do not fill these gaps. They concern planning illustrations and do not specify a missing-data method, multiplicity strategy, or analysis population. With no posted endpoint analyses, the reader cannot determine whether the analysis accounted for repeated measurements, how many comparisons informed any reported conclusion, or how missing observations were treated. These methods are not reported in the registry record.
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 |
|---|---|---|---|
| Arm 1: Intervention - no Cane for First 8 Weeks | 0 | 26 | 0.0% |
| Arm 1 - Intervention - Crossover to Cane | 0 | 26 | 0.0% |
| Arm 2- Single Point Cane | 0 | 27 | 0.0% |
Other (non-serious) adverse events
Participants with at least one non-serious event at or above the registry's 2% reporting threshold.
| Arm | Participants affected of at risk |
|---|---|
| Arm 1: Intervention - no Cane for First 8 Weeks | 0 of 26 |
| Arm 1 - Intervention - Crossover to Cane | 0 of 26 |
| Arm 2- Single Point Cane | 0 of 27 |
The adverse-event record separates three groups: the first 8 weeks without a cane, the crossover to cane use, and the single point cane arm. For the first group, 0 serious adverse events and 0 other adverse events are listed among 26 participants at risk. For the crossover group, 0 serious adverse events and 0 other adverse events are listed among 26 participants at risk. For the single point cane group, 0 serious adverse events and 0 other adverse events are listed among 27 participants at risk.
These are the registry’s recorded event counts for the listed groups. They should not be combined into a new total, particularly because the record describes crossover periods and does not explain how the group records relate at the participant level. The death entries are null, so deaths are not reported in the registry record; null should not be read as a reported count of zero. No serious adverse event terms are listed.
Zero events recorded in these groups does not establish that no events occurred outside the reporting captured in the registry. The adverse-event figures also do not provide information about event surveillance, collection procedures, or completeness. They describe what the registry reports, not a general safety conclusion.
12. What the Result Does, and Does Not, Mean
The trial record addresses a focused biomechanical question: how peak vertical force on the affected limb was measured during gait with and without a single point cane in people with knee osteoarthritis. It identifies a randomized crossover design, the intervention, a comparison condition, and the timing and setting of the primary endpoint. This makes the study question and measurement approach understandable.
The posted results do not include an analyzed endpoint estimate. Without means, standard deviations, a treatment contrast, or an uncertainty interval, the observed direction and magnitude of any difference are not reported. The record therefore does not support a conclusion that cane use did or did not change peak vertical force. It also does not establish equivalence between conditions.
Even if a force difference were reported, that measurement would address a biomechanical outcome rather than directly answer every aspect of the study summary. Pain, disability, and acceptance of cane use are mentioned as interests in the study description, but the listed primary endpoint is peak vertical force. The registry record does not give a numerical result on those other interests.
The safety figures list zero serious and zero other adverse events in each recorded group, while death counts are not reported. Those counts should be interpreted as registry entries, not as proof that no event occurred in all circumstances. The record also lacks details about event ascertainment and completeness.
Overall, the study design and measurement are described, but the clinical and statistical meaning of the primary outcome cannot be determined without endpoint results and analysis details. The registry record’s missing result is not evidence of benefit, harm, or no effect.
13. Why This Trial Matters Statistically
This trial is statistically notable for combining randomization with a crossover structure. Such designs can compare conditions within the same participant, which can be informative when an outcome varies substantially between people. They also require attention to the dependence between repeated observations and to period and sequence. The registry identifies the design but does not report the analysis methods used to handle those features.
The endpoint is a laboratory measure of gait biomechanics, specified as peak vertical force on the affected limb. Its definition is distinct from the broader concerns named in the study summary, including pain, disability, and acceptance. Keeping the measured endpoint separate from those broader questions is important when interpreting what a trial can establish.
The record also illustrates the difference between a described design and an interpretable result. It names the outcome, timing, measurement approach, and arms, but lists zero analyses and no numerical endpoint results. Without an estimate and uncertainty, the reader cannot judge effect magnitude or precision. Design details alone cannot replace those results.
Finally, planning assumptions must be distinguished from observed findings and from the original study rationale. The registry describes assumptions for planning illustrations, but the original sample-size justification and endpoint analysis plan are not reported. These distinctions help prevent a planning quantity from being mistaken for evidence about what the study found.
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 main trial-specific limitation for interpreting the primary outcome is that the registry record lists the endpoint but reports no numerical results or analyses. It gives no means, standard deviations, treatment contrast, confidence interval, or p-value. The size and precision of a difference in peak vertical force therefore cannot be assessed.
The crossover description is not sufficient to reconstruct the full analysis. The record describes the first intervention period and a crossover from no cane to cane use, but does not explain the full timing of later assessments or whether later-period data were included. It does not report handling of within-participant correlation, period effects, sequence effects, or possible carryover. A washout period is not reported in the registry record.
Details needed to evaluate the analysis are also absent. The registry does not report participant-level endpoint counts, missing-data handling, analysis populations, adherence, protocol deviations, or the statistical model. It does not report the randomization procedure or allocation concealment. The absence of these details does not establish that a procedure was or was not used; it means the information is not reported in the registry record.
The record identifies one outcome measure, but it does not describe a multiplicity strategy or clarify which walking-condition contrasts were prespecified. The study summary refers to pain, disability, biomechanics, and acceptance, while the listed primary outcome is a biomechanical force measure. Numerical results for other outcomes are not reported in the registry record. These limits constrain any inference about the endpoint and the broader questions raised by the study.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Walking Aids in the Management of Knee Osteoarthritis — NCT00223795.
- Registry record last updated 2017-11-01; status last verified 2017-09.
- Results first posted 2014-04-22.
- 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.
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18. Record Summary
NCT00223795, titled Walking Aids in the Management of Knee Osteoarthritis, is a completed randomized, unmasked crossover study sponsored by the VA Office of Research and Development. Enrollment was 53. The study examined a single point cane in people with knee osteoarthritis, with a focus on overweight or obese people.
The primary endpoint was peak vertical force on the affected limb, measured in N/kg using an in-shoe dynamic pressure distribution system during laboratory gait evaluations. The described assessments were at baseline and at the end of the first intervention period, specified as 2 months, with walking both with and without a cane. The registry lists one outcome measure and zero analyses.
No numerical primary outcome results are reported in the registry record. Adverse-event entries list zero serious and zero other adverse events in each recorded group; death counts are not reported. The registry does not report the detailed statistical analysis, missing-data methods, or original sample-size justification.