The Effect of Micro Fragmented Adipose Tissue (MFAT) on Knee Osteoarthritis: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for The Effect of Micro Fragmented Adipose Tissue (MFAT) on Knee Osteoarthritis (NCT03467919), a randomized phase 3 study. The primary outcome is Change in Knee Injury and Osteoarthritis Outcomes Score (KOOS) Score - Pain.

2. Clinical Question

3. Trial Design

The registry describes a randomized, single-masked, parallel-group Phase 3 trial sponsored by Stanford University. It lists an enrollment of 40 and a completed status. The trial is described as non-surgical and compares MFAT injection with conventional therapy using an intra-articular corticosteroid injection. The record does not identify who was masked, describe the randomization procedure, or report whether allocation was concealed.

The MFAT arm is described as receiving autologous tissue harvested from the thigh by tumescent lipoaspiration, processed with minimal manipulation, and injected into the knee. The conventional-therapy arm is described as receiving Triamcinolone 40mg. Its description also mentions sham adipose-tissue harvesting without intra-articular injection. These are the treatment descriptions in the registry; further procedural details are not reported in the registry record.

The listed primary outcome is KOOS Pain score, with assessments at baseline, 3, 6, 12, and 24 months. Secondary outcomes include the Lysholm Score and the physical and mental scores of the Veterans RAND 12 (VR-12). The registry lists six outcome measures and 40 analyses, but does not give enough information to determine how each analysis relates to a specific measure, time point, or comparison.

The recorded start date is 2018-04-01 and the primary completion date is 2024-10-29. A protocol, detailed statistical analysis plan, and account of participant flow are not reported in the registry record. In particular, the record does not explain the planned allocation ratio or how follow-up, missing observations, and outcome analyses were handled.

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: 40 participants signed informed consent, 39 received randomized study injection and provided baseline information

Overall Study

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: Participants with data at the respective time point.

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: Participants who started study procedures

6. Primary Endpoint

The registry lists the primary outcome as Change in Knee Injury and Osteoarthritis Outcomes Score (KOOS) Score - Pain, measured over Baseline, 3, 6, 12, and 24 months.

The primary endpoint is change in the Knee Injury and Osteoarthritis Outcomes Score (KOOS) Pain score. This patient-reported measure is described as a normalized score on which 100 indicates no symptoms and 0 indicates extreme symptoms. It is intended to capture participants’ reported pain-related experience rather than an assessment based only on a clinical examination.

Change from baseline can help describe whether scores move over follow-up and how those changes compare between treatment groups. Repeated assessment can also show whether the pattern differs across the follow-up period. The registry lists baseline and follow-up assessments at 3, 6, 12, and 24 months, but does not report the observed scores, changes, or between-group estimates at those points.

In general, a patient-reported outcome is useful when the experience being studied is best represented by the participant’s own report. Interpretation still depends on how the score is analyzed, the amount of missing follow-up data, and the uncertainty around the estimated changes. Those details, including a clinically important threshold for KOOS Pain in this trial, are not reported in the registry record. The listed score scale describes its direction, but does not by itself establish whether any observed difference would be important to participants.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The study is described as randomized, single-masked, and parallel-group. In a randomized trial, assignment is intended to make treatment groups comparable on average with respect to both measured and unmeasured participant characteristics. Randomization does not guarantee balance in a particular trial, especially when the available enrollment is limited. The registry does not describe the sequence-generation method, allocation concealment, or which people were masked. The meaning and effectiveness of masking therefore cannot be assessed from the registry record.

What does a change score represent?

The primary endpoint is a continuous measure: KOOS Pain, summarized in the record as a mean with standard deviation. A change score represents the difference between a participant’s score at follow-up and their baseline score. In general, group averages can describe the average change within each group, while a between-group contrast compares those changes. A different valid approach may compare follow-up scores while accounting for baseline. The registry record does not specify which approach was used or report the relevant estimates.

A mean is a measure of the center of a set of scores. A standard deviation describes how spread out individual scores are around that mean; it is not the uncertainty of the estimated mean. A confidence interval, if reported, would convey the range of values reasonably compatible with the data and analysis assumptions. The registry record does not report means, standard deviations, confidence intervals, or the model used for the primary endpoint, so these quantities cannot be interpreted for this trial.

Why do repeated assessments matter?

The primary outcome is listed at baseline and at several follow-up points. In general, repeated measurements on the same participant are related rather than independent. A statistical model for repeated measures can account for that within-participant relationship and can use observations from more than one follow-up. Analyses at separate time points, by contrast, can produce several estimates and tests. The registry does not state which strategy was planned or used, whether a particular time point was designated as primary, or how the repeated observations were modeled.

General statistical interpretation also distinguishes the estimate from the test of a null hypothesis. An estimate describes the direction and size of an observed contrast; a p-value addresses how compatible the data are with a specified null model under the test’s assumptions. Neither alone expresses clinical importance. A confidence interval helps show precision, but its interpretation also depends on the analysis and data. No such endpoint statistics are reported in the registry record.

What can planning calculations tell a reader?

The record describes planning illustrations based on the observed effect, using a two-sided significance level of 0.05, equal allocation between the two arms, and a normal approximation. The illustrations are framed around detecting a stated fraction of the observed effect; participant counts for these non-time-to-event outcomes are expressed per arm. These are planning calculations, not results observed in a new trial and not observed power. The numerical illustration values and the effect on which they depend are not reported in the registry record, so their magnitude cannot be assessed from the record.

In general, a planning calculation depends on assumptions about the effect to detect, variability, significance level, allocation, and analysis method. Changing an assumed effect changes the planning requirement. A calculation based on an observed effect can be especially uncertain when that effect estimate is imprecise. The record does not report the trial’s own sample-size justification or establish that these illustrative assumptions were used to design the trial.

Why can over-dispersion matter?

For count outcomes, over-dispersion means that the observed variability is greater than expected under a simple model such as a Poisson model. In general, ignoring it can make standard errors too small and confidence intervals too narrow. That issue is not directly an explanation of the primary endpoint here, which is a continuous score. The registry record does not identify a count outcome or report a model requiring an over-dispersion assessment. No claim about such an analysis should be inferred from the trial’s outcome listings.

More broadly, the registry lists six outcome measures and 40 analyses but does not explain the analysis plan, model specifications, covariate adjustments, or hierarchy among outcomes and time points. The posted information therefore supports general explanation of statistical concepts, but not a reconstruction of the trial’s actual analysis.

10. Multiplicity, Missing Data and Analysis Populations

The primary KOOS Pain outcome is listed at baseline and at 3, 6, 12, and 24 months. The registry also lists secondary measures: Lysholm Score and the physical and mental VR-12 scores. It records six outcome measures and 40 analyses. Multiple measures, time points, or analyses can create multiple opportunities to identify an apparently notable result. In general, a prespecified testing strategy can help control the interpretation of this multiplicity.

The registry does not report whether outcomes were arranged in a hierarchy, whether a particular time point was designated as the primary comparison, or whether any multiplicity adjustment was used. It does not describe interim analyses or the statistical analysis plan. These matters are not reported in the registry record, so it is not possible to determine how the analyses were prioritized or how the overall false-positive risk was addressed.

The record defines the primary outcome population as participants with data at the respective time point. It does not report the number with observed outcome data at each assessment, the reasons for missing data, or methods for handling missing observations. In general, analyzing only available observations can be biased if outcome availability is related to treatment or to participants’ outcomes. Methods that address missing data also depend on assumptions, which should be stated and examined. The registry record does not report such methods or sensitivity analyses.

The record does not specify whether the main analysis followed an intention-to-treat principle, how protocol deviations were handled, or whether a per-protocol or other analysis population was used. The exact analysis populations and their definitions are therefore not reported in the registry record.

11. 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.

The registry lists serious adverse events and other adverse events separately for the treatment groups. For the MFAT group, the listed at-risk count is 30 for each category, with 0 serious adverse events, 0 other adverse events, and 0 deaths. For the Conventional Therapy group, the listed at-risk count is 10 for each category, with 0 serious adverse events, 0 other adverse events, and 0 deaths.

These figures describe what is recorded for the listed at-risk participants and categories. They are not a complete account of every possible safety outcome: the record does not provide event narratives, timing, severity beyond the serious-event classification, or information about how events were collected and reviewed. The record also does not explain the relationship between these at-risk counts and the enrollment figure, or provide details about follow-up for safety.

Zero recorded events in these groups should not be read as proof that an intervention has no risks. In general, an observed absence of events is compatible with uncertainty about events that might occur in a broader population or with longer observation. These registry figures alone do not establish comparative safety.

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

The record describes a randomized comparison of intra-articular MFAT with corticosteroid injection in a trial of knee osteoarthritis. It identifies KOOS Pain change as the primary outcome and lists repeated assessments through 24 months. These details define the broad clinical and statistical question, but they do not provide the results needed to answer it.

The registry does not report group outcome scores, changes from baseline, between-group estimates, confidence intervals, or p-values for KOOS Pain. Accordingly, it is not possible to state which group had higher scores, whether the groups differed, or how precisely any difference was estimated. The completed status and recorded enrollment do not supply this missing evidence.

The scale description gives a direction for interpreting scores: 100 indicates no symptoms and 0 indicates extreme symptoms. It does not establish the magnitude of any observed change, whether a difference would matter to participants, or whether scores changed similarly at each follow-up. The registry also does not report a threshold for clinically important change.

In general, an estimate and its uncertainty are needed to distinguish a potentially meaningful pattern from a result that is too imprecise to interpret. Statistical evidence and clinical importance are related but not interchangeable: a statistically detectable difference need not be important to participants, and an imprecise estimate may leave a range of possible effects unresolved. Neither can be evaluated without the outcome estimates and their uncertainty.

The appropriate conclusion from the registry record is therefore limited. It documents the trial design, outcome schedule, and listed safety counts, but does not report the primary comparative result. It cannot, on its own, support a claim that either treatment is better, equivalent, or ineffective.

13. Why This Trial Matters Statistically

This trial is statistically notable because it frames a randomized comparison around a patient-reported pain score measured repeatedly over follow-up. Repeated measurements can describe not only the score at a single visit but also how the measured outcome is tracked over time. They also raise analytic questions about the relationship between observations from the same participant and the handling of incomplete follow-up.

The trial compares an autologous tissue intervention with a corticosteroid injection and includes a sham harvesting element in the conventional-therapy arm description. That design makes clear why accurate reporting of masking, treatment procedures, outcome timing, and analysis populations matters for interpretation. The registry identifies the study as single-masked but does not say who was masked, leaving an important design detail unresolved.

The record lists several outcomes and many analyses. That makes prespecification and multiplicity especially relevant statistical considerations in general. Without a reported analysis plan, readers cannot tell which comparison was prioritized or how secondary and repeated assessments were handled. Similarly, without participant counts at each outcome time point and missing-data methods, the potential influence of incomplete follow-up cannot be assessed.

Most importantly, the registry record illustrates the distinction between a trial’s design and its evidence about outcomes. A completed randomized trial can be described in useful detail while its registry record still lacks the estimates and uncertainty needed for a comparative interpretation. For this trial, the design and endpoint are reported, but the primary outcome results are not reported in the registry record.

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 limitation for interpreting the trial from the registry record is the absence of primary outcome results. No KOOS Pain group means, changes, treatment-effect estimates, confidence intervals, or p-values are reported. Without them, the size, direction, and precision of the comparison cannot be evaluated.

The primary outcome is listed at multiple time points, but the record does not specify which follow-up comparison was primary or describe the analysis used for repeated measures. It also does not report whether any baseline adjustment, covariate adjustment, or multiplicity procedure was used. The listing of six outcome measures and 40 analyses does not by itself reveal which analyses were confirmatory.

The outcome population is described as participants with data at each respective time point. Counts of participants contributing primary outcome data, reasons for missingness, and missing-data methods are not reported in the registry record. The record also does not define the analysis populations or explain how treatment discontinuation and protocol deviations were handled.

Design reporting is incomplete for some interpretive questions. Although the trial is identified as randomized and single-masked, the masking target and randomization details are not reported. The registry does not give a sample-size justification, and the planning assumptions described for illustrative calculations should not be mistaken for the trial’s original design rationale. The record also does not provide a threshold for clinically important KOOS Pain change.

Finally, the adverse-event figures are limited to the listed categories and at-risk counts. The registry does not provide event descriptions or enough detail to assess the completeness of safety follow-up. These limitations restrict conclusions to the design and recorded counts rather than the comparative efficacy or full safety profile.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: The Effect of Micro Fragmented Adipose Tissue (MFAT) on Knee Osteoarthritis — NCT03467919.
• Registry record last updated 2026-01-26; status last verified 2025-12.
• Results first posted 2026-01-26.
• 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.

18. Record Summary

The registry record describes NCT03467919, a completed, randomized, single-masked, parallel-group Phase 3 trial sponsored by Stanford University. It lists enrollment of 40 and compares intra-articular MFAT with conventional therapy consisting of corticosteroid injection.

The primary outcome is change in KOOS Pain score, assessed at baseline, 3, 6, 12, and 24 months. Secondary outcomes include Lysholm Score and the physical and mental VR-12 scores. The primary outcome population is described as participants with data at each respective time point.

The listed safety counts show 0 serious adverse events, 0 other adverse events, and 0 deaths in each group for the corresponding recorded at-risk counts. The registry record does not report the primary outcome results, analysis details, missing-data methods, or multiplicity strategy, so it does not permit a quantitative comparison of the treatments.