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 Efficacy of Micro-fragmented Adipose Tissue Injection for Knee Osteoarthritis. (NCT03379168), a randomized na study. The primary outcome is Change in Visual Analog Pain Scale (VAS) Over Time.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT03379168 |
| Phase | NA |
| Condition | Knee Osteoarthritis |
| Allocation | Randomized |
| Design model | Parallel |
| Masking | Single |
| Enrollment | 75 |
| Arms in the primary outcome | 3 |
| Lead sponsor | Dustin L. Richter, MD |
| Results posted | Yes |
2. Clinical Question
Population
People with symptomatic knee osteoarthritis were eligible for a study of pain and function. The registry record lists knee osteoarthritis as the condition and reports enrollment of 75 participants. Further eligibility criteria and participant characteristics are not reported in the registry record.
Intervention
The intervention was Lipogems, described as lipoaspiration from the abdomen followed by autologous injection of harvested adipose tissue into the knee. The registry record describes the procedure as micro-fragmented adipose tissue injection. Details of the amount injected are not fully reported in the registry record.
Comparator
The comparison groups received an intra-articular corticosteroid injection or a saline placebo injection. The placebo description specifies sterile saline in the affected knee. The corticosteroid description names triamcinolone acetonide mixed with lidocaine.
Primary question
The primary outcome asks how the Visual Analog Scale pain score changed from before the procedure to 2 weeks after it. The posted results give a median improvement and 95% confidence interval for each group. A formal comparison of the groups is not reported in the registry record.
The clinical question is whether pain scores changed over the short interval after each injection procedure, and whether the randomized groups differed. These are distinct questions: the group-specific medians describe change within each group, while estimating a treatment contrast requires a direct between-group analysis. The posted primary results address the first question descriptively but do not report the second. Knee function was also of interest, with WOMAC and KOOS listed as secondary outcomes over time; their results are not reported in the registry record.
3. Trial Design
This completed study is registered as a randomized, single-masked, parallel-group trial of injections for knee osteoarthritis. The registry reports enrollment of 75 participants and lists three groups: placebo injection, corticosteroid injection, and Lipogems injection. The posted primary outcome summaries include 22 participants in the placebo group, 23 in the corticosteroid group, and 23 in the Lipogems group. The registry does not explain the difference between the enrollment figure and the numbers in the primary outcome summaries.
The placebo group received sterile saline in the affected knee. The corticosteroid group received triamcinolone acetonide mixed with lidocaine. The Lipogems group underwent abdominal lipoaspiration, followed by injection of harvested adipose tissue into the knee. Some details in the registry’s intervention description are incomplete, so further procedural specifics are not reported in the registry record.
The trial is listed as starting on 2018-04-01, with primary completion on 2023-04-01, and its status is completed. The registry identifies the primary outcome as change in Visual Analog Scale pain score over time, measured before the procedure and post-procedure at 2 weeks. WOMAC and KOOS changes over time are listed as secondary outcomes. The registry record does not report further details about the randomization sequence, allocation concealment, the identity of the masked parties, or the duration and timing of secondary outcome assessments. The protocol’s sample-size justification and full statistical analysis plan are not reported in the registry record.
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 | Placebo Injection | Corticosteroid Injection | Lipogems Injection |
|---|---|---|---|
| STARTED | 22 | 23 | 23 |
| COMPLETED | 18 | 16 | 18 |
| NOT COMPLETED | 4 | 7 | 5 |
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 | Placebo Injection | Corticosteroid Injection | Lipogems Injection | Total |
|---|---|---|---|---|---|
| Participants analysed | 22 | 23 | 23 | 68 | |
| Age, Continuous | years | 61.2 (SD 10.8) | 56.3 (SD 11.5) | 62.6 (SD 8.4) | 60.0 (SD 10.5) |
| Sex: Female, Male: Female | Participants | 15 | 14 | 8 | 37 |
| Sex: Female, Male: Male | Participants | 7 | 9 | 15 | 31 |
| Race and Ethnicity Not Collected | Participants | — | — | — | 0 |
6. Primary Endpoint
The registry lists the primary outcome as Change in Visual Analog Pain Scale (VAS) Over Time, measured over Prior to procedure then post-procedure at 2 weeks.
| Element | Registry entry |
|---|---|
| Result type | Median |
| Measure of spread | 95% Confidence Interval |
| Unit | Median improvement in VAS pain score |
| Endpoint classification | not reduced to a single comparison |
The primary endpoint is change in knee pain measured with a Visual Analog Scale, or VAS. Participants mark their pain on a 100 mm line anchored at “no pain” and at the most severe pain described in the registry. The distance from the no-pain anchor to the participant’s mark gives a score from 0 to 100. The registry also describes cut points for no, mild, moderate, and severe pain, but the posted primary outcome is the median improvement in score rather than the number of participants in each pain category.
A VAS is used to represent pain on a continuous scale, allowing a change in the marked position to reflect a change in reported pain intensity. The primary assessment compares the pre-procedure measurement with the measurement at 2 weeks after the procedure. A median is a measure of the middle of the observed changes, and the 95% confidence interval communicates uncertainty around that summary. These group-level summaries do not, by themselves, estimate how much one randomized treatment differs from another. The registry does not report a direct contrast between groups or details of how individual changes were analyzed.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The posted primary results are group-specific medians for improvement in VAS pain score from before the procedure to 2 weeks afterward. The placebo group has a median improvement of 1.5, with a 95% confidence interval from 0.0 to 2.5. The corticosteroid group has a median improvement of 2.0, with a 95% confidence interval from 0.0 to 5.0. The Lipogems group has a median improvement of 3.0, with a 95% confidence interval from 1.0 to 4.0. The registry labels the outcome as median improvement in VAS pain score; it does not give a more specific unit for these result values.
These summaries describe change within each randomized group. They do not show whether the changes differ statistically or clinically between groups. The registry record reports no outcome analyses, and no adjusted or unadjusted treatment contrasts, p-values, or confidence intervals for between-group differences are reported in the registry record. Therefore, the listed group medians should not be treated as estimates of comparative treatment effects.
The confidence intervals convey uncertainty about the group summaries, not a range in which every participant’s change lies. Their widths differ across groups, so the precision of the reported medians is not identical. The intervals overlap. Overlap alone is not a formal test of a treatment contrast, and the record does not provide a method for testing the groups against one another. The result summaries also do not establish whether any change is important to participants, because a threshold for interpreting the size of a change is not reported in the registry record.
The registry lists WOMAC and KOOS change over time as secondary outcomes, but does not report their results. The primary endpoint is an early assessment at 2 weeks; later pain or function outcomes are not reported in the registry record. Consequently, the posted data describe short-term group-level VAS changes and their uncertainty, rather than a complete account of outcomes over time or a comparative conclusion about the three interventions.
9. Statistical Methods Explained
The registry describes a randomized, single-masked, parallel-group design. Random allocation is intended to make treatment groups comparable, on average, with respect to characteristics that could affect the outcome. It does not guarantee that groups are identical, particularly in a study of this size. The record does not explain how the random sequence was generated, whether allocation was concealed, or who was masked. Those implementation details are not reported in the registry record.
What does the median describe?
The primary result is a median improvement in VAS pain score for each group. In general, the median is the middle value when observations are ordered. It is useful when a typical value is desired and when a distribution may be asymmetric or affected by unusually large or small observations. Reporting a median does not reveal the full distribution of participant changes. The registry does not report additional summaries, such as individual-level data or a measure of spread beyond the confidence interval.
How should the confidence interval be read?
In general, a confidence interval expresses uncertainty in an estimate under the assumptions of the method used to calculate it. A narrower interval indicates greater precision than a wider interval, though interpretation also depends on the analysis and the data. The registry reports 95% confidence intervals for the group medians, but does not specify the calculation method. These intervals concern the medians within groups. They are not confidence intervals for differences between treatments, and comparing their overlap is not a substitute for a direct contrast.
Why is a direct comparison needed?
A within-group change can reflect several influences, including the intervention, the passage of time, expectations, and features of measurement. Randomization supports a comparison between assigned groups, but the relevant treatment effect is estimated by contrasting outcomes across groups using an analysis suited to the design and endpoint. The posted results contain group summaries, not a reported contrast. The registry records zero analyses, and a formal statistical test, effect estimate, or confidence interval for a comparison is not reported in the registry record. It is therefore not possible to infer a comparative result from the group medians alone.
What do the planning assumptions mean?
General sample-size planning asks how many participants would be needed to detect a specified effect under stated assumptions. The planning illustrations associated with these results use a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation; the target effect is a stated fraction of the observed effect. They are planning illustrations, not the trial’s own design justification and not evidence of observed power. A sample size calculated from an observed effect is sensitive to uncertainty in that effect, and it does not establish that a study was adequately designed or that an effect is real. The registry’s own sample-size justification is not reported in the registry record. No numerical planning estimates are stated in the registry information.
Over-dispersion is a general concern when outcomes vary more than a statistical model assumes: the model may understate uncertainty and make evidence appear more precise than it is. The registry does not report a model-based analysis or diagnostics for over-dispersion. Because the primary summaries are medians with confidence intervals and the calculation method is not specified, no particular distributional or model assumption can be attributed to the analysis.
The primary outcome is measured from before the procedure to 2 weeks after it. A change score summarizes the difference between those measurements for each participant, then the group median summarizes those changes. The record does not describe how missing measurements were handled, whether adjustments were made for baseline scores, or which analysis population was used. Those choices can affect estimates and uncertainty, so their absence limits assessment of the analysis.
10. Multiplicity, Missing Data and Analysis Populations
The registry lists the primary VAS outcome and two secondary outcomes: change in WOMAC over time and change in KOOS over time. The posted primary results contain group-level VAS summaries, while results for the secondary outcomes are not reported in the registry record. No analysis results are listed for the outcomes, and the record does not identify a statistical analysis plan specifying which comparisons or time points were intended to be confirmatory.
Multiplicity is a general issue when several outcomes, time points, or group comparisons are tested. The more opportunities there are to declare a result statistically significant, the greater the chance of a misleading positive finding if no strategy accounts for those tests. A prespecified hierarchy or adjustment can help address that issue. Whether either approach was used is not reported in the registry record. Since no inferential comparisons are posted, there are no reported multiplicity-adjusted or unadjusted p-values to interpret.
Missing-data handling and analysis populations are also not reported in the registry record. The primary summaries give group sizes of 22, 23, and 23, while total enrollment is listed as 75; the record does not explain the relationship between these counts or identify exclusions, withdrawals, or missing endpoint measurements. It does not say whether the analysis followed randomized assignment, included only participants with observed outcomes, or used another population definition. No imputation method, sensitivity analysis, or assessment of missingness is described. These omissions prevent evaluation of how incomplete follow-up may have affected the posted estimates.
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 |
|---|---|---|---|
| Placebo Injection | 0 | 22 | 0.0% |
| Corticosteroid Injection | 0 | 23 | 0.0% |
| Lipogems Injection | 0 | 23 | 0.0% |
Deaths
| Arm | Deaths (participants affected of at risk) |
|---|---|
| Placebo Injection | 0 of 22 |
| Corticosteroid Injection | 0 of 23 |
| Lipogems Injection | 0 of 23 |
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 |
|---|---|
| Placebo Injection | 0 of 22 |
| Corticosteroid Injection | 0 of 23 |
| Lipogems Injection | 0 of 23 |
Most frequent non-serious adverse event terms
| Event term | Organ system | Placebo Injection | Corticosteroid Injection | Lipogems Injection |
|---|---|---|---|---|
| Expected minor adverse event | Skin and subcutaneous tissue disorders | 0 of 22 | 0 of 23 | 0 of 23 |
The adverse-event figures list 22 participants at risk in the placebo group, 23 in the corticosteroid group, and 23 in the Lipogems group. For each group, the registry reports zero participants affected by a serious adverse event and zero affected by another adverse event in the categories shown. Deaths are also recorded as zero in each group. No serious adverse-event terms are listed.
These figures should be read as registry-recorded events for the participants represented in each group, not as proof that no harm occurred. The record does not provide further definitions, event-collection procedures, observation duration, or details about whether all participants were assessed for the same length of time. It also does not give event narratives or severity information beyond the categories recorded. A zero count in the posted data means that no event is recorded in that category; it does not establish that an intervention is free of risk. The safety information is therefore limited to the counts and group sizes reported, and should not be interpreted as a complete characterization of safety.
12. What the Result Does, and Does Not, Mean
The posted results give a descriptive account of median VAS improvement at 2 weeks in each randomized group, alongside confidence intervals for those medians. They make the group-specific estimates and their uncertainty visible. They do not report a direct comparison of Lipogems with saline or corticosteroid, so they cannot establish the size or statistical uncertainty of a treatment contrast. The registry does not report p-values or a formal inferential analysis for the primary outcome.
The results also do not answer whether any observed change is large enough to matter to participants. Although the registry describes VAS pain categories, it does not state a threshold for a meaningful change, nor does it report the proportion of participants who reached such a threshold. Group medians cannot show how consistently individuals improved, remained unchanged, or worsened.
The assessment is at 2 weeks after the procedure. The registry lists changes in WOMAC and KOOS over time as secondary outcomes but does not report their results. It therefore does not establish longer-term pain or functional outcomes from the posted data. The adverse-event counts are zero in the categories shown, but the record does not provide enough detail to treat those counts as proof of absence of risk.
In general, a randomized comparison can help separate treatment differences from other influences, but interpretation depends on complete outcome reporting, appropriate analysis, and clear follow-up information. Important details about missing data, analysis populations, and the statistical plan are not reported in the registry record. The appropriate reading is limited to the posted group summaries and recorded event counts, without turning them into a conclusion about comparative effectiveness or safety.
13. Why This Trial Matters Statistically
This trial is statistically notable because its primary outcome is reported as a median improvement with a confidence interval for each of three randomized groups. That format communicates group-level change and uncertainty, but it does not itself answer the comparative question raised by a randomized design. A direct contrast is needed to estimate how outcomes differ between assigned groups and to quantify uncertainty in those differences.
The distinction matters especially when several groups have changes from baseline. A change within a group is not the same estimand as a difference between groups. The placebo group also has a reported median improvement, illustrating why a treatment’s within-group change should not automatically be attributed to the treatment itself. Without a reported between-group analysis, readers cannot assess the comparative estimate or its precision from the registry record.
The record also identifies WOMAC and KOOS as secondary outcomes, but does not report their results or describe how multiplicity was handled. This illustrates how outcome registration and outcome reporting are both important: naming outcomes indicates what was intended to be measured, while complete results are needed to evaluate the evidence across endpoints and time points. Details about missing data and the analysis population are likewise important for understanding who contributed to the estimates.
Finally, sample-size planning and observed results answer different questions. Planning illustrations based on an observed effect are not a substitute for the trial’s original sample-size justification and are not observed power. The registry’s design justification is not reported in the registry record. Keeping these distinctions clear helps prevent descriptive summaries from being overread as definitive comparative evidence.
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.
Several trial-specific limitations of interpretation arise from the registry information. The primary outcome is assessed at 2 weeks after the procedure, so the posted result concerns an early follow-up point. The registry lists WOMAC and KOOS outcomes over time, but does not report their results or clarify the time points for those assessments. Longer-term outcomes are not reported in the registry record.
The primary results are medians with confidence intervals for each group, without a reported between-group estimate or statistical test. The registry also does not state the method used to calculate the confidence intervals. The reported group sizes are 22, 23, and 23, while enrollment is listed as 75; the reason for the difference is not reported in the registry record. Eligibility criteria, baseline participant characteristics, withdrawals, and outcome completeness are also not reported in the registry record.
The record identifies the design as randomized, single-masked, and parallel-group, but does not describe sequence generation, allocation concealment, or who was masked. Details of the statistical analysis plan, analysis populations, missing-data methods, multiplicity control, and sample-size justification are not reported in the registry record. The Lipogems procedure description is incomplete, so some procedural details are not reported in the registry record. These gaps limit assessment of both the trial’s conduct and the precision and applicability of the posted results.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Efficacy of Micro-fragmented Adipose Tissue Injection for Knee Osteoarthritis. — NCT03379168.
- Registry record last updated 2025-02-13; status last verified 2025-02.
- Results first posted 2023-12-21.
- 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
The registry record describes a completed, randomized, single-masked, parallel-group study of injections for knee osteoarthritis, with enrollment of 75 participants. The three groups received placebo saline, corticosteroid, or Lipogems micro-fragmented adipose tissue injection. The primary endpoint was median improvement in VAS pain score from before the procedure to 2 weeks afterward.
Posted median improvements were 1.5 for placebo, 2.0 for corticosteroid, and 3.0 for Lipogems, each with a 95% confidence interval. No formal between-group analysis is reported in the registry record. WOMAC and KOOS changes over time are listed as secondary outcomes, but their results are not reported. The adverse-event categories shown record zero serious events, other events, and deaths in each group. Analysis-plan details, missing-data methods, and the trial’s sample-size justification are not reported in the registry record.