Intraarticular Dextrose Prolotherapy for Symptomatic Knee Osteoarthritis: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Intraarticular Dextrose Prolotherapy for Symptomatic Knee Osteoarthritis (NCT05160532), a randomized phase 2 study. The primary outcome is Change in Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) Total Score.

2. Clinical Question

3. Trial Design

The registry record describes a randomized, double-masked, parallel-group Phase 2 study of intraarticular dextrose prolotherapy for symptomatic knee osteoarthritis. The listed enrollment is 48. The record gives a study start date of 2022-04-10, a primary completion date of 2025-05-31, and a status of completed. These registry entries describe the study record; they do not provide a report of the primary outcome analysis.

Participants were assigned to one of four injection schedules: four placebo injections; one DPT injection followed by three placebo injections; two DPT injections and two placebo injections; or four DPT injections. All injections are described as intraarticular knee injections under ultrasound guidance. The registry calls the study randomized and double-masked, but does not report the method used to generate or conceal the allocation, which parties were masked, or whether masking was assessed. It also does not report the allocation ratio.

The primary outcome is change in WOMAC Total Score, measured at Baseline and Week 4, Week 8, Week 16, Week 26 and Week 52. Listed secondary outcomes concern change in pain and in WOMAC physical function, stiffness and pain scores. The registry record does not describe the statistical analysis plan, the method for handling repeated measurements, or the planned contrasts among the four schedules. Those details are important for interpreting how the trial was intended to answer its research question, and 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.

Before assignment: 5 subjects were enrolled but withdrew prior to randomization.

Overall Study

Analysis population for the primary outcome, as defined in the registry: 1 sbjt in 2DPT/2placebo arm didnt completed WOMAC at baseline \& week 4. 1 in 4 placebo arm, 1 in 1DPT/3placebo, \& 1 in 4DPT arm didnt complete WOMAC at week 4 \& week 16. 1 in 1DPT/3placebo arm \& 1 in 4DPT arm didnt complete WOMAC at week 8. 2 in 2DPT/2placebo arm didnt complete WOMAC at week 16. 2 in 4placebo arm, 2 in 1DPT/3placebo arm \& 3 in 4DPT arm didnt complete WOMAC at week 26. 3 in 2DPT/2placebo arm didnt complete WOMAC at week 26. 5 in 2DPT/2placebo arm didnt complete WOMAC at week 52

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.

6. Primary Endpoint

The registry lists the primary outcome as Change in Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) Total Score, measured over Baseline; Week 4; Week 8; Week 16; Week 26; Week 52.

The primary endpoint is change in the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) Total Score. The registry describes WOMAC as a disease-specific measure of physical function, pain and stiffness in people with knee osteoarthritis. It reports that total scores range from 0-96, with higher scores indicating worse outcome.

A combined score can provide a broad measure of the symptoms and functional impact that the trial is studying. Looking at change over time focuses on how a participant’s measured score differs from the designated baseline assessment, rather than interpreting a single follow-up score in isolation. The registry lists assessments at Baseline and Week 4, Week 8, Week 16, Week 26 and Week 52. It does not specify in the primary outcome description which follow-up time is the principal comparison for a single treatment-effect estimate.

Using a disease-specific measure makes the endpoint relevant to the condition under study, but a total score can also conceal different patterns across its component domains. The listed secondary outcomes separately address pain, physical function and stiffness. The registry record does not report the primary endpoint’s observed means, changes, between-group estimates, confidence intervals or statistical tests, so the magnitude and precision of any treatment contrast cannot be described from the recorded results.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The statistical ideas below are general explanations for reading a randomized trial. The registry record does not report the statistical analysis plan or primary outcome analysis results for this study.

What does randomization contribute?

In general, random assignment aims to make treatment groups comparable in expectation with respect to both measured and unmeasured characteristics at the start of a trial. It supports a fair comparison of assigned strategies when the allocation process is implemented appropriately and participants are analyzed in a way consistent with the intended comparison. Randomization does not guarantee that groups will be identical, particularly in a study with limited enrollment. The record identifies the study as randomized, but does not report the sequence-generation or allocation-concealment methods.

What does masking mean?

In general, masking can reduce the influence of expectations on participants’ reports, clinical decisions and outcome assessment. The registry calls this study double-masked, but does not specify which people were masked or how masking was maintained. Placebo injections are described as resembling the study drug while containing no active ingredient. The record does not report whether participants or study personnel could infer treatment assignment during follow-up.

How should repeated measurements be understood?

The primary outcome is listed at Baseline and at Week 4, Week 8, Week 16, Week 26 and Week 52. Repeated measurements can describe the time course of an outcome, but measurements from the same participant are generally related rather than independent. General analysis approaches can account for this within-participant correlation, or can compare changes at selected time points. The choice of approach affects the estimate and its uncertainty. The registry record does not report which method was used or which time point was designated as the principal treatment comparison.

What does a confidence interval communicate?

In general, a confidence interval describes the precision of an estimated effect under the assumptions of the statistical model and analysis. A narrower interval indicates greater precision than a wider interval, while an interval spanning values compatible with different directions or magnitudes signals substantial uncertainty. A confidence interval is not a guarantee that the true effect lies within its limits. No primary outcome confidence intervals are reported in the registry record, so the precision of the trial’s treatment comparisons cannot be assessed from the record.

What can a p-value say?

In general, a p-value measures how incompatible the observed data are with a specified null hypothesis, given the statistical model and its assumptions. It does not measure the probability that the null hypothesis is true, the size of an effect, or its clinical importance. The registry record does not report primary outcome p-values or specify the null hypotheses tested. A p-value, even if available, would need to be interpreted alongside the effect estimate, confidence interval, analysis plan and outcome context.

Why do multiple arms and time points matter?

Comparing several schedules and examining multiple follow-up times creates more than one possible statistical contrast. In general, testing many contrasts can raise the chance that at least one result appears statistically notable by chance. A prespecified primary contrast or an appropriate multiplicity strategy can help frame interpretation. The registry lists several arms and outcome times, but does not report a multiplicity plan, a prespecified hierarchy of comparisons or the final analyses. The primary outcome is also identified in the registry as having several categories or time points and is not reduced there to one comparison.

How should sample-size illustrations be read?

In general, a planning illustration based on an observed effect describes the number of participants per arm that might be needed under stated assumptions to detect an effect of a chosen size. It is a planning exercise, not evidence that the original trial had that level of power and not an estimate of the probability that the study detected an effect. The record’s planning assumptions describe a two-sided significance level of 0.05, equal allocation between two arms, a normal approximation and effects defined as fractions of an observed effect. The registry does not report a sample-size justification for the trial’s original design. Any planning figures should therefore be read as illustrations rather than as the trial’s observed power.

These general concepts clarify what information is needed for a complete statistical interpretation. For this trial, the registry record does not report the outcome estimates or analysis details needed to apply them to the primary comparison.

10. Multiplicity, Missing Data and Analysis Populations

The primary outcome is observed at multiple scheduled time points, and the trial has four injection schedules. This creates multiple possible comparisons across groups and time. In general, when many statistical tests are considered, the chance of at least one apparently notable result can increase. A prespecified primary contrast, testing hierarchy or multiplicity adjustment can help control or contextualize this issue. The registry record does not report such a plan, the number of primary comparisons tested, or primary outcome analyses. The registry notes that the primary outcome has several categories or time points and is not reduced to one comparison.

The registry describes incomplete WOMAC assessments in several arms. It reports that one participant in the two-DPT/two-placebo arm did not complete WOMAC at baseline and Week 4. At Week 4 and Week 16, it reports one participant in each of the placebo-only, one-DPT/three-placebo and four-DPT arms did not complete WOMAC. At Week 8, one participant in the one-DPT/three-placebo arm and one in the four-DPT arm did not complete WOMAC. At Week 16, it also reports that two participants in the two-DPT/two-placebo arm did not complete WOMAC.

These notes identify missing assessments but do not explain why data were missing, whether the same participants were missing at more than one time, or how missing values were handled in the analysis. In general, missing-data methods rely on assumptions about the relationship between missingness and observed or unobserved outcomes. The analysis population, missing-data assumptions, imputation methods and sensitivity analyses are not reported in the registry record. It is therefore not possible to determine whether the primary analysis used all randomized participants or how sensitive its results were to incomplete follow-up.

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.

Most frequent non-serious adverse event terms

The registry record reports serious adverse event counts by injection schedule. Serious adverse events affected 0 of 11 participants at risk in the four-placebo group, 0 of 11 in the one-DPT/three-placebo group, 0 of 10 in the two-DPT/two-placebo group and 0 of 11 in the four-DPT group. Deaths are reported as 0 in each of these groups. These are the counts recorded in the registry, not evidence that such events are impossible or that the schedules have equivalent safety.

Other adverse events are listed as affecting 1 of 11 participants at risk in the four-placebo group, 1 of 11 in the one-DPT/three-placebo group, 0 of 10 in the two-DPT/two-placebo group and 1 of 11 in the four-DPT group. The registry record does not provide the terms or descriptions for these other adverse events, their timing, severity or relationship to treatment. It also does not report a statistical comparison of safety outcomes between schedules.

Adverse-event counts are descriptive and should be read with their group-specific numbers at risk. They do not by themselves establish a difference between schedules, particularly when the event counts are small. The registry record does not report further safety analyses.

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

The registry record establishes that a randomized, double-masked, parallel-group Phase 2 trial of DPT schedules for symptomatic knee osteoarthritis was completed. It identifies WOMAC Total Score change as the primary outcome and lists multiple assessment times. It also records serious adverse events, other adverse events and deaths by study group. These details describe the registered study and its reported safety counts.

What the record does not establish is the size or direction of any difference in WOMAC change between injection schedules. It reports no primary outcome estimates, confidence intervals or statistical tests. The status of completed does not itself mean that outcome results are available in the registry record. Without those results, the relative outcome patterns cannot be quantified, and the precision of any comparison cannot be evaluated.

The endpoint is a total score covering physical function, pain and stiffness. It offers a broad measure of the condition-specific outcome, while the listed secondary outcomes address pain and WOMAC domains separately. The registry record does not report those outcome results either. No conclusion about the clinical importance of a change can be drawn from the endpoint description alone.

The safety counts are also limited. No serious adverse events or deaths are recorded in the listed groups, while other adverse events are recorded in some groups. The event descriptions and comparative safety analyses are not reported. Those counts should not be treated as proof of equal safety or as a complete characterization of potential harms.

In short, the record describes a trial designed to examine different injection frequencies and provides selected design and safety information. It does not report the primary outcome analysis needed to determine how the schedules compared. Any stronger claim about benefit, lack of benefit or comparative safety would exceed the information in the registry record.

13. Why This Trial Matters Statistically

This trial is statistically interesting because it compares several schedules rather than only an active treatment with a placebo-only control. The arms represent placebo-only injections, two mixed DPT/placebo schedules and a DPT-only schedule. This design can, in principle, examine whether outcomes vary with injection frequency, but interpretation depends on which contrasts were planned and how they were analyzed. Those details are not reported in the registry record.

The primary endpoint is measured repeatedly from baseline through Week 52. Repeated outcome data can show whether group patterns differ over time, but they also raise questions about within-participant correlation, missing assessments and the choice of a primary time point or summary. The record identifies incomplete WOMAC assessments at several times and in several groups, while leaving the missing-data method and analysis population unreported.

Multiple arms and outcome times also create a multiplicity concern. Without a reported analysis plan, readers cannot identify which comparisons were primary, whether other comparisons were exploratory, or whether adjustments were used. This limits the ability to interpret any isolated result should one be reported separately from a fuller analysis.

The registry record is useful for identifying the intended outcome framework and the amount of detail available about safety. However, it reports no primary outcome estimates or statistical tests. The central statistical lesson is that a trial design and a completed status do not substitute for an analyzed treatment contrast with its uncertainty. The outcome analysis and its methods are necessary to assess what the study’s data support.

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 limitations follow from the information recorded for this trial. Most importantly, the registry record does not report the primary outcome results. There are no arm-level WOMAC means or change estimates, between-group contrasts, confidence intervals or p-values. Consequently, the magnitude, direction and precision of any differences between injection schedules are not available for interpretation.

The primary outcome is listed at multiple time points, but the registry record does not identify a single primary time-point comparison or explain how repeated measurements were analyzed. It also does not report the planned contrasts among the four schedules or any multiplicity strategy. These omissions make it difficult to determine how the study’s central question was operationalized statistically.

The record notes incomplete WOMAC assessments in several arms and at several visits, but does not describe reasons for missingness or the methods used to address it. The analysis population, assumptions about missing data and any sensitivity analyses are not reported. Without this information, the potential effect of incomplete follow-up on the primary analysis cannot be assessed.

The registry describes the study as randomized and double-masked but does not report the allocation procedure or which parties were masked. It does not provide detailed participant characteristics, eligibility criteria, or a sample-size justification. The planning assumptions recorded for sample-size illustrations do not establish the rationale for the original enrollment.

Safety information is limited to group-level counts. Descriptions of other adverse events and comparative safety analyses are not reported. These limitations concern what can be learned from the registry record; they do not establish what was or was not included in analyses outside that record.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Intraarticular Dextrose Prolotherapy for Symptomatic Knee Osteoarthritis — NCT05160532.
• Registry record last updated 2026-06-30; status last verified 2026-06.
• Results first posted 2026-06-30.
• 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 NCT05160532, a completed randomized, double-masked, parallel-group Phase 2 trial sponsored by Mayo Clinic. It lists enrollment as 48 and concerns symptomatic knee osteoarthritis. The study compares four ultrasound-guided injection schedules involving placebo and dextrose prolotherapy: placebo only, two mixed schedules, and DPT only.

The primary outcome is change in WOMAC Total Score, with assessments listed from Baseline through Week 52. Secondary outcomes concern pain and WOMAC physical function, stiffness and pain. The record includes group-level adverse event counts and notes incomplete WOMAC assessments at several visits.

Primary outcome estimates, statistical tests, confidence intervals, detailed analysis methods and a sample-size justification are not reported in the registry record. As a result, the comparative outcome effect and its precision cannot be determined from the recorded information.