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 StepRite Evaluation (NCT02270684), a randomized na study. The primary outcome is Knee Osteoarthritis Outcome Score (KOOS).
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT02270684 |
| Phase | NA |
| Condition | Osteoarthritis |
| Allocation | Randomized |
| Design model | Parallel |
| Masking | Single |
| Enrollment | 4 |
| Arms in the primary outcome | n/a |
| Lead sponsor | University of Southern California |
| Results posted | Yes |
2. Clinical Question
Population
Adults after total knee arthroplasty with osteoarthritis. The study enrolled 4 participants.
Intervention
StepRite device use, with a remote physical-therapist visit replacing one in-person visit per week during outpatient treatment.
Comparator
Usual and customary care without being issued the StepRite device.
Primary question
Whether short-term changes in gait parameters and functional outcomes differ between the two care approaches after total knee arthroplasty.
The registry describes a randomized, parallel-group trial comparing an activity-specific monitoring device with usual care. Its stated purpose was to compare short-term changes after total knee arthroplasty. The primary outcome measure was the Knee Osteoarthritis Outcome Score (KOOS), described as a validated tool for measuring pain and quality of life in patients after total knee arthroplasty.
The KOOS was scheduled for assessment at baseline and at 4, 10, and 24 weeks. The registry's primary-outcome entry states that, because the study terminated early, no evaluable data were collected. Consequently, the record cannot answer whether KOOS outcomes differed between groups. It also does not report an analyzed comparison of gait parameters or functional outcomes.
The clinical question is therefore identifiable from the trial description, but the posted results do not provide an estimate of the difference between StepRite and usual care. Details such as eligibility criteria beyond the stated population, the exact gait parameters, and the intended definition of short-term change are not reported in the registry record.
3. Trial Design
This was a randomized, single-masked, parallel-group study listed with phase not applicable. The registry identifies the sponsor as the University of Southern California and lists osteoarthritis as the condition. Enrollment was 4. The study started in 2015-05, had a primary completion date of 2016-01, and is marked terminated.
Participants were assigned to a StepRite device arm or a usual and customary care arm. The StepRite arm description says that participants would receive the device and have a remote visit with their physical therapist in place of one in-person visit per week during the outpatient phase of treatment. The comparator arm description says participants would receive usual care and would not be issued the device.
Although the record identifies the study as randomized and single-masked, it does not explain how the random sequence was generated, how assignment was concealed, or who was masked. The allocation ratio and any procedures for maintaining masking are not reported in the registry record. The parallel model indicates that the arms were separate groups rather than a crossover arrangement, but the record does not provide further design detail.
The trial's primary outcome was KOOS, with assessments listed at baseline, 4, 10, and 24 weeks. The primary-outcome entry states that early termination meant no evaluable data were collected. The reason for termination, the intended recruitment target, and the protocol's analysis plan are not reported in the registry record. Thus the listed design describes the comparison that was planned, while the posted results do not supply an evaluable clinical 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.
Overall Study
| Stage | Device | Usual and Customary Care |
|---|---|---|
| STARTED | 1 | 3 |
| COMPLETED | 0 | 0 |
| NOT COMPLETED | 1 | 3 |
Reasons for not completing this period:
| Reason | Device | Usual and Customary Care |
|---|---|---|
| Lost to Follow-up | 0 | 3 |
| Study terminated | 1 | 0 |
Analysis population for the primary outcome, as defined in the registry: Due to early termination, no evaluable data was collected
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 | Device | Usual and Customary Care | Total |
|---|---|---|---|---|
| Participants analysed | 1 | 3 | 4 | |
| Age, Categorical: <=18 years | Participants | 0 | 0 | 0 |
| Age, Categorical: Between 18 and 65 years | Participants | 0 | 0 | 0 |
| Age, Categorical: >=65 years | Participants | 1 | 3 | 4 |
| Sex: Female, Male: Female | Participants | 1 | 2 | 3 |
| Sex: Female, Male: Male | Participants | 0 | 1 | 1 |
| Region of Enrollment: United States | participants | 1 | 3 | 4 |
6. Primary Endpoint
The registry lists the primary outcome as Knee Osteoarthritis Outcome Score (KOOS), measured over Baseline, 4, 10, 24 weeks.
| Element | Registry entry |
|---|---|
| Result type | N/A |
| Measure of spread | not applicable |
| Unit | not stated |
| Endpoint classification | not reduced to a single comparison |
The primary endpoint was the Knee Osteoarthritis Outcome Score (KOOS). The registry describes KOOS as a validated tool for measuring pain and quality of life in patients after total knee arthroplasty. A patient-reported measure can capture aspects of symptoms and everyday impact that may not be represented by a clinical or device measurement alone. This is a general reason such measures are used; it does not establish what effect StepRite had in this study.
The listed assessment schedule was baseline and 4, 10, and 24 weeks. The record does not identify a single one of these time points as the sole endpoint, nor does it state which KOOS score or subscale was intended for the primary comparison. The unit, parameter, and dispersion are not reported in the registry record. The outcome entry says no evaluable data were collected because of early termination.
As a result, the record supplies the measure's purpose and its planned timing, but not observed KOOS values, a change estimate, or a between-group contrast. A validated instrument can help make a measurement meaningful and consistent, but validation does not compensate for the absence of trial outcome data. The registry record therefore does not establish whether pain or quality-of-life scores changed, or whether any changes differed by assigned arm.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry record documents a randomized comparison of StepRite with usual and customary care after total knee arthroplasty, with 4 participants enrolled. It also documents that the trial was terminated and that no evaluable primary-outcome data were collected. Those details are central to interpreting the record: the planned clinical question is described, but there is no posted KOOS result with which to estimate a treatment-group difference.
No effect estimate, confidence interval, or statistical test for the primary outcome is reported. The registry lists 0 analyses. This means the posted results do not quantify the direction, magnitude, or precision of a KOOS contrast. It would be inappropriate to infer that the approaches had similar results, that one was better, or that an effect was absent. An unreported or unestimated difference is not evidence that the true difference is zero.
The listed assessment times—baseline, 4, 10, and 24 weeks—describe the planned outcome schedule, not completed observations. Without evaluable outcome data, there is no observed trajectory to compare over time. The registry's stated purpose also mentions gait parameters and functional outcomes, but it does not report an analyzed result for those measures.
The adverse-event entries report 0 serious adverse events among 1 participant at risk in the Device group and 0 among 3 at risk in the Usual and Customary Care group. They also report 0 other adverse events among 1 and 3 participants at risk, respectively. These small counts describe the posted record only. They do not establish a comparative safety profile or show that events could not occur. Death counts are not reported in the registry record.
In general, a confidence interval communicates the range of effect estimates compatible with the data and the statistical procedure used. No primary-outcome confidence interval is reported, so the precision of a clinical effect cannot be assessed. The sample-size assumptions describe planning illustrations based on an observed effect, but do not supply an observed primary result or a justification for the trial's enrollment. These illustrations are not observed power.
Overall, the posted information supports a description of the intended trial and its limited recorded safety counts. It does not support an efficacy conclusion, a precise effect estimate, or a finding of equivalence between the groups. The reason for early termination and any sponsor analysis beyond the registry entries are not reported in the registry record.
9. Statistical Methods Explained
The trial is identified as randomized, single-masked, and parallel. In general, random assignment is intended to make the groups comparable with respect to both measured and unmeasured characteristics, on average. That design property does not guarantee balance in any particular small study, and it does not itself show that an intervention has an effect. The registry record does not report the randomization sequence method, assignment concealment, or the identity of the masked party.
A parallel-group design assigns participants to one of the study arms and compares outcomes between those groups. Here the listed arms are StepRite and usual and customary care. The device-arm description includes a remote physical-therapist visit in place of one in-person visit per week during outpatient treatment, while the usual-care arm is described as not receiving the device. The registry does not detail whether other aspects of care were standardized or how treatment receipt and adherence were measured.
What would a between-group estimate represent?
In general, a treatment-effect estimate compares outcomes under the assigned strategies. For a continuous score such as a patient-reported measure, an analysis might compare group means, changes from baseline, or another prespecified summary. Which summary is appropriate depends on the protocol and the data structure. The registry record does not report the intended KOOS estimand, model, or contrast. It reports no analyses, and its primary-outcome entry states that no evaluable data were collected after early termination. Therefore, no numerical treatment-effect estimate can be interpreted from the posted results.
The KOOS assessment schedule includes baseline, 4, 10, and 24 weeks. Repeated measurements can be analyzed in several ways in general, including by comparing change from baseline or modeling outcome values across time. Such methods need a defined outcome, assumptions about the correlation among repeated measurements, and a plan for incomplete follow-up. None of the specific model choices or assumptions are reported in the registry record. The listed time points alone do not establish which comparison was planned.
How should uncertainty be understood?
In general, a confidence interval expresses uncertainty around an estimated effect under a specified statistical model. A narrow interval indicates greater precision than a wide interval, while an interval that includes values on both sides of no difference can be compatible with several interpretations. This is a general explanation, not a description of an interval in this trial: no primary-outcome estimate or confidence interval is reported. Without an estimate and its uncertainty, the magnitude and precision of any possible group difference cannot be evaluated.
Statistical significance is also distinct from clinical importance. In general, a p-value addresses how surprising data would be under a specified null model and analysis assumptions; it does not give the probability that a treatment works, and it does not measure the size or importance of an effect. No p-value for the primary outcome is reported in the registry record. Accordingly, there is no reported test on which to base a significance claim.
Planning illustrations are not trial results
General sample-size calculations depend on choices such as the significance level, power target, allocation, variability, and effect size to be detected. The registry's planning-assumption description specifies a two-sided significance level of 0.05, equal allocation, and a normal approximation, with the target effect expressed as a fraction of an observed effect. It also distinguishes participant counts per arm from total event counts for time-to-event calculations. These are calculation assumptions, not a reported account of the trial's original design justification.
The record does not report a sample-size justification or say that those planning assumptions were used to set enrollment. Planning illustrations based on an observed effect should not be mistaken for evidence that the trial had adequate power or for observed power. In particular, the record reports no evaluable primary outcome from which to interpret an observed clinical effect. Any sample-size illustration is hypothetical planning information rather than a result from participants.
Why can over-dispersion matter?
In general, over-dispersion occurs when observed variability in data exceeds what a statistical model assumes. If ignored, standard errors and confidence intervals can be misleading, especially for count outcomes. A model may need to account for extra variability, but the appropriate approach depends on the outcome and design. The registry record does not report an over-dispersion assessment or model, and there is no reported primary-outcome analysis to evaluate. This general concept should not be read as evidence that over-dispersion occurred in this study.
The registry's main statistical limitation is not a reported modeling choice but the absence of evaluable primary-outcome data and analyses. Without those, no method can produce a defensible outcome comparison from the posted record. The intended analysis details, including handling of repeated measures and any covariate adjustment, are not reported in the registry record.
10. Multiplicity, Missing Data and Analysis Populations
The primary outcome lists KOOS assessments at baseline, 4, 10, and 24 weeks. When multiple time points or outcome measures are considered, multiplicity can arise if several comparisons are tested and the chance of a false-positive finding is not addressed. In general, a prespecified primary comparison and a stated adjustment strategy help readers understand which result carries the principal inference. The registry record does not report a multiplicity strategy or identify one assessment time as the sole primary comparison.
The registry says the primary outcome has several categories or time points and was not reduced to one comparison. It reports 0 analyses, and the outcome entry states that early termination meant no evaluable data were collected. Thus there is no posted result from which to determine how multiplicity was handled in practice. Whether additional outcomes were planned, and whether any hierarchy or adjustment was specified, are not reported in the registry record.
Missing-data methods are also not reported. The statement that no evaluable data were collected because of early termination indicates that the primary outcome does not have an analyzable result in the posted record. It does not describe why each participant lacked evaluable data, how much information was available at individual time points, or whether any imputation or other missing-data approach was considered. These details are not reported in the registry record.
The record also does not define an analysis population, such as an intention-to-treat or per-protocol population, or explain how participants would be included in the planned analysis. These are general design and analysis distinctions, not evidence of a particular approach in this trial. With no evaluable primary data and no reported analysis, readers cannot assess the consequences of missing outcomes, deviations from assignment, or selective choice among comparisons.
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 |
|---|---|---|---|
| Device | 0 | 1 | 0.0% |
| Usual and Customary Care | 0 | 3 | 0.0% |
Other (non-serious) adverse events
Participants with at least one non-serious event at or above the registry's 0% reporting threshold.
| Arm | Participants affected of at risk |
|---|---|
| Device | 0 of 1 |
| Usual and Customary Care | 0 of 3 |
The registry records 0 serious adverse events among 1 participant at risk in the Device group and 0 among 3 participants at risk in the Usual and Customary Care group. For other adverse events, it records 0 among 1 at risk in the Device group and 0 among 3 at risk in the Usual and Customary Care group. These are the counts and denominators posted for the two groups.
In general, a count of zero means that no event of that category was recorded among the listed participants at risk. It does not establish that the underlying risk is zero, particularly when the number of participants is small. It also does not establish that risks are the same between groups. A comparative safety estimate would require an appropriate analysis and uncertainty assessment; neither is reported in the registry record.
The deaths entry is null for both groups, so death counts are not reported in the registry record. The record does not provide event definitions, observation duration for safety, or further detail about the adverse-event collection process. The posted counts should therefore be read as limited descriptive information, not as a complete assessment of comparative safety.
12. What the Result Does, and Does Not, Mean
The record establishes that a randomized, parallel-group study was intended to compare StepRite with usual and customary care after total knee arthroplasty. It identifies KOOS as the primary outcome measure, lists its planned assessment times, and describes the device and comparator approaches. It also records enrollment of 4 participants and states that the trial terminated early.
The most important result for interpreting the clinical question is that no evaluable primary-outcome data were collected. There is consequently no posted estimate of KOOS change, no between-group difference, and no confidence interval or p-value for that comparison. The record cannot show whether scores changed over time or whether the groups differed. Nor can it establish that the approaches were equivalent or that any difference was absent.
The adverse-event counts show no serious or other adverse events recorded in the small listed groups. These counts do not prove that there was no risk or that the groups had the same risk. Death counts are not reported in the registry record. More generally, the absence of analyzable efficacy outcomes and the limited safety counts place substantial limits on what can be concluded from these results.
The registry record is informative about the intended question and the study's status, but it does not provide the evidence needed to estimate an effect. The reason for termination, the intended statistical analysis, the planned enrollment target, and the handling of missing data are not reported in the registry record. These omissions prevent assessment of why the planned comparison could not be completed and how a full analysis would have been conducted.
Thus, the appropriate interpretation is descriptive: a small randomized study was listed, it was terminated, and its primary outcome was not evaluable. This record alone neither supports a claim of benefit nor supports a claim of no effect.
13. Why This Trial Matters Statistically
Statistically, this study illustrates the difference between a clearly stated clinical question and an answerable outcome comparison. The registry describes a randomized comparison, identifies a patient-reported primary measure, and specifies assessment times. But a design description does not substitute for observed outcome data. Because the primary-outcome entry states that no evaluable data were collected, the planned comparison cannot be estimated from the posted results.
The enrollment of 4 is important context for reading the record, but the central limitation is not merely the size of the enrollment: no evaluable primary outcome and no analyses are reported. In general, a small sample can yield imprecise estimates, but precision cannot be assessed in the absence of an estimate and its uncertainty. It would therefore be misleading to turn the record into a conclusion about the size or direction of a treatment effect.
The case also shows why reporting the status of a trial matters. The record marks the study terminated and explains that early termination left no evaluable data for the primary outcome. This makes clear that the missing result is not a neutral or null estimate. The reason for termination and the original analysis plan are not reported in the registry record, so the circumstances behind the incomplete outcome evidence remain unclear.
Finally, the listed adverse-event counts illustrate the limits of interpreting zeros in small groups. They communicate what was recorded, but do not establish absence of risk or comparative safety. Taken together, these features make the record useful for understanding the intended design and the limits of the evidence, while leaving the clinical effect question unanswered.
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 principal trial-specific limitation is early termination with no evaluable data for the primary KOOS outcome. The record reports enrollment of 4, but offers no primary-outcome observations, effect estimate, confidence interval, or analysis. The reason for termination is not reported in the registry record, so the cause and timing of the interruption cannot be assessed from the posted information.
The trial's stated purpose includes short-term changes in gait parameters and functional outcomes, but the record does not report analyzed results for these measures. It identifies KOOS as the primary measure and lists baseline, 4, 10, and 24 weeks as assessment times, but does not identify a single primary time-point contrast. The KOOS unit, parameter, and dispersion are not reported in the registry record.
Important design and analysis details are not reported in the registry record, including the method of randomization, allocation concealment, identity of the masked party, allocation ratio, sample-size justification, and statistical analysis plan. The record also does not state the intended analysis population or missing-data methods. These absences limit assessment of how the planned comparison would have been carried out.
Safety information is limited to the posted event counts and participants at risk. The entries show 0 serious adverse events and 0 other adverse events in both groups, with 1 participant at risk in the Device group and 3 in the Usual and Customary Care group. Death counts are not reported in the registry record. Event definitions, collection procedures, and duration of safety follow-up are also not reported.
These limitations mean that the registry record supports a description of the planned comparison and its incomplete outcome reporting, but not an estimate of clinical effectiveness or comparative safety.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: StepRite Evaluation — NCT02270684.
- Registry record last updated 2017-05-11; status last verified 2017-04.
- Results first posted 2017-05-11.
- 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
The registry record describes a randomized, single-masked, parallel-group study of StepRite versus usual and customary care after total knee arthroplasty. It lists osteoarthritis as the condition, identifies the University of Southern California as sponsor, and reports enrollment of 4. The study started in 2015-05, had a primary completion date of 2016-01, and is marked terminated.
The primary outcome was KOOS, scheduled at baseline and at 4, 10, and 24 weeks. The outcome entry states that early termination meant no evaluable data were collected. The record lists 0 analyses. It reports 0 serious and 0 other adverse events among 1 participant at risk in the Device group and among 3 participants at risk in the Usual and Customary Care group. Death counts are not reported in the registry record.
The posted information describes the planned comparison but does not provide an evaluable primary-outcome result or a treatment-effect estimate.