Hyaluronic Acid vs Platelet Rich Plasma: Effects on Clinical Outcomes and Intra-articular Biology for the Treatment of Knee Osteoarthritis: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Hyaluronic Acid vs Platelet Rich Plasma: Effects on Clinical Outcomes and Intra-articular Biology for the Treatment of Knee Osteoarthritis (NCT02588872), a randomized na study. The primary outcome is International Knee Documentation Committee Score (IKDC.

2. Clinical Question

The central comparison is between two injection regimens in a randomized, parallel-group trial. The clinical outcome is a patient-reported knee-function score, not a direct measure of joint biology. The registry describes the IKDC scale as ranging from 1 to 100, with higher scores indicating better function. The trial also planned to examine other patient-reported measures and synovial-fluid markers, but those address different aspects of the treatment comparison.

The registry record gives group means and an unadjusted comparison for the IKDC outcome. Those numbers describe the participants included in the posted final analysis; they do not by themselves establish why the groups differed or whether any difference is important to patients. The reported score comparison is also an estimate with uncertainty, so its confidence interval matters alongside the point estimate and p-value.

The registry does not report a threshold for a clinically important IKDC difference, nor does it report the original sample-size justification. Consequently, the posted results can describe the observed score contrast and its statistical precision, but cannot establish from the registry alone whether the contrast crossed a prespecified threshold of clinical importance.

3. Trial Design

The registry describes a prospective randomized controlled trial with a parallel-group allocation. The trial status is completed, and the recorded enrollment is 111. The registered condition is knee osteoarthritis. The registry lists three masking roles, while the brief study summary describes the study as double-blind. The exact roles behind the masking designation and any differences in terminology are not reported in the registry record.

Participants were assigned to platelet-rich plasma or hyaluronic acid. Both regimens consisted of three weekly injections delivered into the affected knee under ultrasound guidance. The platelet-rich plasma is described as leukocyte-poor and without buffer or additive; the hyaluronic acid is described as ultra high molecular weight hyaluronan. Further details about how the allocation sequence was generated, concealed, or implemented are not reported in the registry record.

The study summary describes collection of subjective outcome measures before treatment and at four time intervals over a one-year period. It also describes synovial-fluid collection before treatment and at 12 and 24 weeks for analysis of pro- and anti-inflammatory markers. The registry lists the IKDC score as the primary outcome, with assessment described as change from pretreatment to an average of one year after treatment.

For the posted primary outcome, the final analysis included 50 participants in the hyaluronic acid group and 49 in the platelet-rich plasma group. The registry says 9 hyaluronic acid participants and 3 platelet-rich plasma participants were lost to follow-up from the original cohort. The analysis population and handling of missing outcomes beyond that statement are not reported in the registry record. The registry also lists secondary outcomes including the Visual Analogue Scale, the Western Ontario and McMaster Universities Arthritis Index, the Lysholm Knee Score, and synovial-fluid testing.

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

Analysis population for the primary outcome, as defined in the registry: 9 HA patients and 3 PRP from the original cohort were lost to follow up which is why 50 HA and 49 PRP patients were included in final analysis.

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 International Knee Documentation Committee Score (IKDC, measured over This will be assessed as a change from pre-treatment visit to 1 year post treatment..

The primary endpoint is the International Knee Documentation Committee score, a patient-reported measure of knee function. The registry describes a scale from 1 to 100, where higher scores indicate better function. It says the primary outcome is assessed as change from the pretreatment visit to an average of one year after treatment. The posted results give group means and their standard errors for the final analysis groups.

A patient-reported function scale can capture how participants experience their knee, including aspects that may not be represented by a laboratory measure alone. This makes it relevant to a trial comparing interventions intended for symptomatic knee osteoarthritis. The outcome is distinct from synovial-fluid biology: changes in inflammatory markers would address biological activity, whereas the IKDC score addresses reported function.

The registry record does not describe the precise scoring or transformation used for the change outcome, and the posted values do not separately display baseline scores and follow-up scores. Therefore, the group means should be read in conjunction with the registry’s stated endpoint timeframe, while recognizing that the exact construction of the reported change measure is not reported in the registry record. The record also does not state a threshold for a clinically important difference. Statistical evidence about a group contrast and evidence about its clinical importance are related but not interchangeable.

7. Results Posted in the Registry

• Platelet-rich Plasma (PRP): mean 55.80 versus 65.50 on control; difference -9.70 (95% CI -19.96 to 0.56), standardized effect d = -0.37; z-test p = 0.064.

8. Secondary Efficacy Endpoints

The registry also posts results for secondary outcomes. For each outcome below, the endpoint type, the test applied to the posted summary statistics, the result and its interpretation are given in turn. Secondary endpoints are usually not adjusted for multiple testing, so they support rather than confirm the primary finding.

Visual Analogue Scale (VAS)

• Endpoint type: Continuous: a mean value per participant, compared as a difference in means.
• Test: Unadjusted two-sample z-test for the difference in means, using the posted standard errors.
• Result:
  • Platelet-rich Plasma (PRP): mean 44.00 versus 57.30 on control; difference -13.30 (95% CI -24.99 to -1.61), standardized effect d = -0.45; z-test p = 0.026.
• Interpretation:
  • The 95% confidence interval excludes no difference, so the mean is statistically lower for Platelet-rich Plasma (PRP) than for the control. This is an unadjusted, secondary comparison, so it is suggestive rather than confirmatory.

Western Ontario and McMaster Universities Arthritis Index

• Endpoint type: Continuous: a mean value per participant, compared as a difference in means.
• Test: Unadjusted two-sample z-test for the difference in means, using the posted standard errors.
• Result:
  • Platelet-rich Plasma (PRP): mean 3.02 versus 4.00 on control; difference -0.98 (95% CI -2.49 to 0.53), standardized effect d = -0.26; z-test p = 0.202.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between Platelet-rich Plasma (PRP) and the control. The interval gives the range of effects that remain compatible with the data.

Lysholm Knee Score

• Endpoint type: Continuous: a mean value per participant, compared as a difference in means.
• Test: Unadjusted two-sample z-test for the difference in means, using the posted standard errors.
• Result:
  • Platelet-rich Plasma (PRP): mean 65.50 versus 55.80 on control; difference 9.70 (95% CI -0.56 to 19.96), standardized effect d = 0.37; z-test p = 0.064.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between Platelet-rich Plasma (PRP) and the control. The interval gives the range of effects that remain compatible with the data.

The secondary outcomes cover several domains: pain-related rating, arthritis-related symptoms and function, knee function, and synovial-fluid biology. The posted numeric comparisons concern the Visual Analogue Scale, the Western Ontario and McMaster Universities Arthritis Index, and the Lysholm Knee Score. The registry also lists biologic testing of synovial fluid, but does not post a numerical comparison for that outcome among the results. The registry record lists no reported analyses for the posted secondary outcomes.

The secondary estimates do not all point in the same direction: the platelet-rich plasma group has a lower posted mean on the Visual Analogue Scale and the arthritis index, but a higher posted mean on the Lysholm score. The registry does not specify in the outcome descriptions how to interpret the direction of change for every measure, so these patterns should not be converted into a broad claim that one group performed better across all outcomes. The primary IKDC comparison itself has an interval that includes zero, and the secondary findings do not resolve that uncertainty.

Several outcomes create a multiplicity concern. If many comparisons are considered separately, some may look noteworthy by chance, even when there is no underlying group difference. The registry does not report an adjustment for multiple comparisons, a prespecified hierarchy for the secondary outcomes, or a confirmatory interpretation plan. Therefore, unadjusted secondary p-values carry less weight than results from a prespecified, appropriately analyzed primary endpoint. They may help describe patterns for further study, but should not be treated as independent confirmation of a treatment effect.

The secondary results also share limitations with the primary result: final analysis counts are stated for the patient-reported comparisons, while the handling of missing data and analysis populations is not fully documented. The registry does not provide detailed biological assay results or explain how missing synovial-fluid samples were handled. Those gaps prevent a complete assessment of consistency between patient-reported outcomes and intra-articular biology.

Secondary outcomes registered for this trial, for reference (only those above were recalculated):

• Visual Analogue Scale (VAS)
• Western Ontario and McMaster Universities Arthritis Index
• Lysholm Knee Score
• Biologic Testing of Synovial Fluid Via ELISA Assays

9. Statistical Interpretation

10. Statistical Methods Explained

What do the group means describe?

A mean is the arithmetic average of the recorded values in a group. For the primary outcome, the posted means are 65.5 for hyaluronic acid and 55.8 for platelet-rich plasma, with standard errors of 3.6 and 3.8, respectively. The registry describes the IKDC scale as a 1-to-100 scale, with higher scores indicating better function. Because the registry characterizes the endpoint as change from pretreatment to one year, interpretation of the posted means depends on the outcome construction; details beyond the stated timeframe are not reported in the registry record.

A standard error describes the statistical uncertainty in an estimated mean, rather than the spread of individual participant scores. It is not interchangeable with a standard deviation. The registry reports standard errors for the group summaries and gives a pooled standard deviation for the unadjusted comparisons. These are different descriptions of variability and serve different purposes in analysis.

What does the mean difference express?

The mean difference is calculated as the platelet-rich plasma group mean minus the hyaluronic acid group mean. For the primary outcome, the recalculated difference is -9.7. This sign convention means a negative estimate corresponds to a lower posted mean in the platelet-rich plasma group. The point estimate condenses the group contrast to one number, but does not show how uncertain that contrast is. The estimate is a simple unadjusted recalculation from the posted summary statistics, not a reported adjusted model.

Random allocation can support a fair comparison by balancing, on average, factors known and unknown at assignment. In practice, interpretation still depends on how randomization was performed, how follow-up was handled, and whether the analysis retained the intended randomized comparison. Details about sequence generation, allocation concealment, and the analysis population are not reported in the registry record.

How should the confidence interval and p-value be read?

A confidence interval is an uncertainty range for an estimate under the statistical model used. The primary comparison’s interval is -19.96 to 0.559. Since it includes zero, the interval is compatible with a range of contrasts that includes no average difference. A p-value of 0.064 summarizes the compatibility of the observed data with a null comparison under the assumptions of the unadjusted test. It does not measure the probability that either treatment is effective, and it does not quantify the probability that the result arose by chance.

These inferential quantities are recalculated from the posted summaries. The registry record lists no reported analyses for the primary endpoint, so the recalculated values should not be mistaken for a sponsor-reported analysis plan or model. The registry does not report whether the original investigators used covariate adjustment, repeated-measures methods, or other procedures for their analysis.

Why does multiplicity matter?

When a study evaluates multiple outcomes or comparisons, the chance of finding at least one apparently unusual result can increase if each is judged separately using an unadjusted threshold. This is the general statistical reason that a prespecified outcome hierarchy and multiplicity procedure can matter. The registry lists several secondary outcomes but does not report a multiplicity adjustment or a plan for interpreting secondary comparisons. The unadjusted secondary p-values therefore require caution and should not be read as if they were independent confirmatory tests.

What do the planning illustrations mean?

The planning figures are illustrations based on the observed effect, not the original trial design. They use a two-sided significance level of 0.05, equal allocation between the two arms, and a normal approximation. Each scenario considers an effect equal to a stated fraction of the observed effect. The figures express participants per arm for the stated power levels. The original trial’s design assumptions and sample-size justification are not reported in the registry record.

In general, statistical power is the chance that a study will meet a specified decision criterion if a particular effect is present and the statistical assumptions hold. The 80% and 90% columns are planning targets, not descriptions of what was achieved in the completed trial. Power calculations depend on the assumed effect and variability as well as the design and analysis. Smaller target effects require more participants to distinguish them from random variation with the same planning targets.

More generally, over-dispersion means that observed variability is greater than a statistical model assumes. If present and unaccounted for, it can make standard errors too small and confidence intervals too narrow. The registry record does not report an over-dispersion assessment, and the continuous outcomes are not presented as count outcomes. This general concept should not be taken as a claim that over-dispersion occurred in this trial.

11. Confidence Intervals and Precision

The primary estimate is a mean difference of -9.7 points, with a 95% confidence interval from -19.96 to 0.559 and an unadjusted p-value of 0.064. The interval includes zero. It therefore does not establish a clear nonzero average contrast under the unadjusted comparison, while remaining compatible with a range of negative values and a small positive value. The registry’s description of the IKDC scale indicates that higher scores represent better function, but the registry does not give a threshold for deciding whether any particular difference is clinically important.

Precision refers to how narrowly an estimate is determined by the data and model. A narrower interval would indicate less statistical uncertainty, while a wider interval would indicate more. The primary interval spans both sides of zero and is not narrow enough to determine the direction of the population contrast with confidence. This is a statement about the estimate’s uncertainty, not proof that the groups are equivalent.

The interval and p-value are unadjusted recalculations from the posted summary statistics. The registry record does not report a sponsor analysis for the primary endpoint, nor does it provide the original analysis model. The interval should therefore be understood as a simple comparison based on the posted means and standard errors, not as a comprehensive analysis accounting for all design or missing-data features.

Uncertainty also applies to the reported group means. Their standard errors are 3.6 and 3.8. Standard errors describe uncertainty around estimated means, not the range of scores among individual participants. The registry does not provide participant-level distributions or baseline group summaries for this outcome, so the extent of individual variation and the evolution of scores from pretreatment cannot be assessed from the posted results alone.

12. Planning a Similar Trial: Sample Size

This is a planning illustration, not a re-evaluation of the original trial. It asks: if a new study wanted to detect a difference like the one observed, or a smaller one, how large would it need to be? It is deliberately not “observed power” of the finished trial, which is not a meaningful quantity.

The planning figures are participants per arm for 80% power and participants per arm for 90% power. They are not total event counts: the outcomes are continuous, and the stated planning convention is participants per arm. The planning assumptions are a two-sided significance level of 0.05, equal allocation between the two arms, and a normal approximation. Each illustration uses the stated fraction of the observed effect as the effect to detect. The original trial’s own design assumptions and sample-size justification are not reported in the registry record.

The 80% power column means that, under the planning assumptions and if the selected effect were present, the proposed design would have an 80% chance of meeting the specified statistical criterion. The 90% power column uses a higher target chance under those same assumptions. These are planning concepts, not guarantees that a future study will reach a particular result. The figures also depend on treating the observed effect as a basis for planning, even though the observed estimate itself is uncertain.

Rows using a smaller fraction of the observed effect require more participants per arm than rows using the full observed effect. That pattern reflects a general principle: smaller differences are harder to distinguish from random variation, so more information is needed to reach the same power target. The figures are illustrations rather than a reconstruction of the decisions made when this trial was designed. They are not observed power.

13. How the Sample Size Is Derived

Power is the probability that a study of a given size rejects the null hypothesis when a specific true effect exists. It depends on four things: the effect to detect, the variability of the outcome, the significance level (here a two-sided α of 0.05, so z_1−α/2 = 1.960) and the desired power (z_1−β = 0.842 for 80% and 1.282 for 90%).

Formula

n is the number of participants in each arm, Δ is the difference in means to detect and σ is the common standard deviation.

Worked calculation for this trial

1. Observed difference Δ = -9.700; pooled standard deviation σ = 26.028.
2. n = 2 × (1.96 + 0.842)² × 26.028² / -9.700² = 113.0, rounded up to 114 participants per arm for 80% power.

The smaller-effect rows in the table above repeat the same calculation with the effect multiplied by 0.75 and 0.5 (for ratios, applied to the logarithm of the ratio).

R code

alpha <- 0.05
z_a   <- qnorm(1 - alpha / 2)          # two-sided
delta <- -9.7                      # observed difference in means
sigma <- 26.028311310777                     # pooled standard deviation
n_per_arm <- function(power, frac = 1) {
  ceiling(round(2 * (z_a + qnorm(power))^2 * sigma^2 / (delta * frac)^2, 6))
}
for (f in c(1, 0.75, 0.5))
  cat(sprintf("%3.0f%% of observed effect: n per arm = %s (80%% power), %s (90%% power)\n", 100 * f,
              format(n_per_arm(0.80, f), big.mark = ","), format(n_per_arm(0.90, f), big.mark = ",")))

# Check against R's built-in function (t-based, so very slightly larger)
cat("power.t.test:", round(power.t.test(delta = delta, sd = sigma, power = 0.80)$n, 1), "\n")

# Simulation: exact two-sample t-test using simulated means and variances
set.seed(2588872)
n    <- n_per_arm(0.80)
reps <- 20000
m_diff <- rnorm(reps, delta, sigma * sqrt(2 / n))             # difference in sample means
s2     <- sigma^2 * rchisq(reps, 2 * (n - 1)) / (2 * (n - 1))   # pooled sample variance
tstat  <- m_diff / sqrt(s2 * 2 / n)
cat(sprintf("Simulated power at n = %s per arm: %.3f (%d replicates)\n", format(n, big.mark = ","), mean(abs(tstat) > qt(0.975, 2 * (n - 1))), reps))

Output from running the code

100% of observed effect: n per arm = 114 (80% power), 152 (90% power)
 75% of observed effect: n per arm = 201 (80% power), 269 (90% power)
 50% of observed effect: n per arm = 453 (80% power), 606 (90% power)
power.t.test: 114 
Simulated power at n = 114 per arm: 0.799 (20000 replicates)

The simulation draws many sets of group means and variances at the planned sample size and counts how often the two-sample t-test rejects the null. It should land close to the target power; at very small required sample sizes it can fall below it, because the normal approximation is rough there.

14. Multiplicity, Missing Data and Analysis Populations

The registry identifies the IKDC score as the primary outcome and lists multiple secondary measures. It does not report a multiplicity adjustment, a testing hierarchy, or a plan for controlling the overall chance of false-positive findings across outcomes. As a general statistical matter, separately testing many outcomes without adjustment can make apparently small p-values more likely to occur even when there are no true group differences. This concern is especially relevant when interpreting secondary comparisons, whose p-values are unadjusted recalculations from posted summary statistics.

The registry lists no reported analyses for the primary or secondary outcomes. It therefore does not document the model used by the investigators, whether the primary analysis was adjusted, how repeated observations were treated, or whether the analysis was specified before results were known. The recalculated estimates describe simple unadjusted comparisons; they do not establish what analysis method the investigators used.

For the primary outcome, the registry says 9 participants in the hyaluronic acid group and 3 in the platelet-rich plasma group were lost to follow-up, and states that the final analysis included 50 and 49 participants, respectively. Reasons for loss to follow-up, timing of loss, and any relationship to outcomes are not reported in the registry record. The record does not describe imputation, sensitivity analyses, or other methods for dealing with missing scores.

The registry also does not state whether all randomized participants were analyzed in their assigned groups, whether participants who did not receive the full injection series were retained, or whether any exclusions occurred beyond the stated losses. Without these details, it is not possible to determine whether the reported estimates represent an intention-to-treat analysis or another analysis population. These limitations do not prove that the analysis was biased; they mean the registry record does not provide enough information to assess the issue fully.

15. Safety Results

The registry reports serious adverse events as affected participants divided by participants at risk.

Other (non-serious) adverse events

Participants with at least one non-serious event at or above the registry's 0% reporting threshold.

The registry reports zero serious adverse events among 59 participants at risk in the hyaluronic acid group and among 52 participants at risk in the platelet-rich plasma group. It also reports zero other adverse events among the same respective at-risk groups. No serious adverse-event terms are listed. These counts describe the safety information posted in the registry and should be read with the stated at-risk denominators.

The safety denominators differ from the final analysis counts reported for the primary outcome. They should not be treated as interchangeable populations or combined with the outcome counts. The registry does not provide further detail about how adverse events were defined, collected, graded, or attributed to treatment. Death counts are not reported in the registry record. Zero posted events should be interpreted as the registry’s reported count, not as proof that no events occurred outside the recorded reporting scope.

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

The results describe a randomized comparison of two injection regimens and report group means for a patient-reported knee-function outcome at the stated one-year timeframe. The observed IKDC mean was higher in the hyaluronic acid group than in the platelet-rich plasma group. The unadjusted recalculated contrast is -9.7 points for platelet-rich plasma relative to hyaluronic acid, with a confidence interval that includes zero. This result conveys uncertainty about the size and direction of the underlying average contrast.

The estimate does not establish that the groups are equivalent. Showing no statistically clear difference is not the same as demonstrating that two treatments have equivalent effects; equivalence requires a prespecified margin and a design and analysis intended to test that question. The registry record does not report such a margin or an equivalence analysis.

Nor does statistical significance alone determine whether a difference matters to patients. The registry describes the direction of the IKDC scale but does not report a clinically important difference threshold. The results therefore cannot establish from the record alone whether the observed contrast, or the values within its confidence interval, are meaningful in clinical terms.

The findings apply to the participants and methods represented in this trial record. Demographic characteristics, detailed eligibility criteria, reasons for attrition, and the full analysis plan are not reported in the registry record. The secondary outcomes add descriptive information, but their unadjusted nature and multiplicity concerns limit their confirmatory value. The safety record reports no adverse events in the posted categories among the listed participants at risk, while providing limited information about ascertainment and no reported death counts.

Overall, the record supports a cautious account of the observed summaries and their uncertainty, not a definitive conclusion about comparative clinical benefit, biological mechanism, or safety beyond the reported event counts. Those broader conclusions require information and analyses not reported in the registry record.

17. Why This Trial Matters Statistically

This trial is statistically interesting because it places a patient-reported knee-function outcome alongside secondary measures that span symptoms, function, and synovial-fluid biology. That design raises a useful interpretive distinction: different outcomes can address different questions, and a biological measurement does not automatically confirm a patient-reported outcome or vice versa.

The primary comparison also illustrates why the estimate, confidence interval, and p-value should be read together. The group means have a visible ordering, but the unadjusted interval includes zero and the p-value is 0.064. Reporting only the direction of the means would omit important uncertainty; reporting only the p-value would omit both the estimated size and the range of values compatible with the data.

The record makes attrition visible by stating the losses to follow-up and the final group counts. That information is relevant because the available outcome summaries are based on fewer participants than the recorded enrollment. At the same time, the record does not explain missing-data handling or provide enough detail to assess the analysis population. This illustrates why transparent reporting of participant flow and analytic decisions is central to interpreting randomized trials.

Finally, the registry’s multiple listed outcomes underscore the distinction between exploratory and confirmatory evidence. Without a reported multiplicity strategy or detailed analysis plan, secondary patterns can be described but should not be treated as a collection of independent proofs. The planning illustrations also offer a practical reminder that smaller target effects generally require larger studies, while not serving as evidence about the power actually achieved by this completed trial.

18. 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 constrain interpretation of the posted results. The registry reports losses to follow-up of 9 participants in the hyaluronic acid group and 3 in the platelet-rich plasma group, but does not report reasons for loss, outcome status among those participants, or missing-data methods. The final analysis therefore reflects the stated final groups, and the extent to which missing outcomes could affect the comparison cannot be assessed from the record.

The registry record does not provide baseline characteristics, detailed eligibility criteria, or participant-level outcome distributions. It also does not provide baseline group scores alongside the posted means, making it difficult to evaluate the starting comparability of the outcome scores or reconstruct the stated change measure. The precise relationship between the listed group summaries and the described change from pretreatment is not further explained.

Although the registry describes randomization and lists triple masking, the brief summary calls the study double-blind. The record does not identify the masked roles or provide the allocation-generation and concealment procedures. It also does not report the investigators’ analysis model, a multiplicity strategy, or a clinical-importance threshold for the primary outcome. These omissions limit assessment of bias, statistical choices, and clinical interpretation.

The registry lists synovial-fluid biological testing but does not provide numerical results for that outcome in the posted outcomes. Safety reporting gives event counts and at-risk denominators, but further details about event definitions and ascertainment are not reported. These are limitations in the available registry record and do not establish that the trial procedures themselves were inadequate.

19. Related Tutorials

20. Related Statistical Calculators

21. Sources

• ClinicalTrials.gov: Hyaluronic Acid vs Platelet Rich Plasma: Effects on Clinical Outcomes and Intra-articular Biology for the Treatment of Knee Osteoarthritis — NCT02588872.
• Registry record last updated 2023-03-14; status last verified 2023-03.
• Results first posted 2017-05-18.
• 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.

22. Record Summary

The registry describes a completed prospective randomized parallel-group trial comparing platelet-rich plasma with hyaluronic acid injections for mild to moderate symptomatic knee osteoarthritis. Recorded enrollment was 111. Both groups received three weekly ultrasound-guided injections. The primary outcome was the IKDC score, described as change from pretreatment to an average of one year after treatment.

The final primary-outcome analysis included 50 participants in the hyaluronic acid group and 49 in the platelet-rich plasma group, following reported losses to follow-up. The posted means were 65.5 and 55.8, respectively. The unadjusted recalculated mean difference was -9.7, with a confidence interval from -19.96 to 0.559 and p = 0.064. The interval includes zero. The registry lists secondary patient-reported outcomes and synovial-fluid testing, but no reported analyses. Safety counts show zero serious and zero other adverse events in the posted at-risk groups; deaths are not reported in the registry record.