MONOVISC for Hip Joint Pain Relief Due to Osteoarthritis: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for MONOVISC for Hip Joint Pain Relief Due to Osteoarthritis (NCT04204083), a na na study. The primary outcome is Numerical Rating Scale (NRS) Pain on Walking.

2. Clinical Question

In plain terms, the study asks how walking-related hip pain scores changed over the follow-up period among participants receiving the injection. Because the study has one treatment group, any change is observed over time within that group; it is not a direct estimate of how outcomes would differ from those under another treatment or no injection. The record also identifies secondary measures: the Lequesne Hip Index Score, Patient Global Assessment, the OMERACT-OARSI Responder Index, and the number of participants not using rescue acetaminophen or paracetamol. Numerical results for these measures are not reported in the registry record.

3. Trial Design

The registry describes a prospective, single-group study of a single MONOVISC injection for symptomatic osteoarthritis of the hip. The intervention is listed as a device, and the treatment description specifies injection into the index hip joint. The study was sponsored by Anika Therapeutics, Inc. Its stated purpose was to obtain real-world, post-market data concerning clinical improvement and safety.

Enrollment was 25 participants. The record lists the study as completed, with a start date of 2019-12-17 and a primary completion date of 2021-02-26. Phase is listed as NA. Allocation is also listed as NA, and masking is listed as none. The model is single group. These design details mean there is no randomized or masked comparison group described in the record. The registry explicitly notes that the arms are not a like-for-like control comparison.

The primary outcome is mean change in Numerical Rating Scale (NRS) pain on walking in the index hip from baseline to 6 months after injection. The primary population is identified as ITT. The record lists five outcome measures and three analyses. It names the Lequesne Hip Index Score, Patient Global Assessment, OMERACT-OARSI Responder Index, and use of rescue acetaminophen or paracetamol among the secondary outcomes.

The registry record does not report a protocol-based sample-size justification, a detailed statistical analysis plan, interim analyses, or numerical primary outcome results. It also does not report the analysis methods used for the listed secondary outcomes. Consequently, the design can be described from the registered information, but the record does not support a full assessment of how the planned analyses were implemented.

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: Only one hip \[Index Hip\] of each participant was included in this study

Overall Study

Analysis population for the primary outcome, as defined in the registry: Intent To Treat (ITT)

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 Numerical Rating Scale (NRS) Pain on Walking, measured over From Baseline to 6 Months.

The primary endpoint is mean change in NRS pain on walking in the index hip, measured from baseline to 6 months after injection. The NRS is described as an 11-point scale, with 0 meaning no pain and 10 meaning worst pain. The registry defines a larger negative value for change from baseline as indicating less pain and a better outcome following treatment. The endpoint is specified as a mean, with standard deviation as the measure of dispersion.

Pain while walking focuses the rating on a particular activity rather than asking only about pain in general. In general, a numerical rating scale can make a subjective experience recordable in a consistent format and can be summarized across participants. A change score compares each participant's follow-up score with that participant's baseline score, then the group mean describes the average change in the outcome population. The spread of scores matters too: a mean alone does not show how similar or varied individual responses were.

The registry identifies the ITT population for this primary measure. However, it does not report the observed mean change, its standard deviation, a confidence interval, or a test result. Therefore the direction and precision of the observed primary outcome cannot be assessed from the registry record. The scale definition explains how a reported change would be interpreted, but does not establish what change occurred.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

Statistical methods are easiest to interpret when the outcome, target population, summary statistic, uncertainty measure, and comparison are all clear. For this study, the registry identifies a continuous primary outcome: change in walking-related hip pain on an 11-point NRS. It specifies the mean and standard deviation, the period from baseline to 6 months, and the ITT population. The record does not report the resulting mean, standard deviation, confidence interval, or p-value. It also does not give enough detail to verify which specific statistical test or model was used.

What does a mean change describe?

A change score is based on the difference between a participant's follow-up measurement and baseline measurement. The group mean summarizes the average of those individual changes. For this NRS, the registry states that a larger negative change corresponds to less pain. In general, a mean is a compact description of the group, but it can conceal variation: participants may have changes that differ substantially even when the average is near a particular value. The standard deviation describes the spread of observations around the mean; it is not the same as uncertainty about the mean.

In general, a confidence interval expresses a range of estimates compatible with the data and the method used, reflecting sampling uncertainty. Its width is relevant to precision: a narrower interval generally indicates a more precise estimate under the assumptions of the analysis. The registry record does not report a confidence interval for the primary outcome, so the precision of the mean change cannot be evaluated from the posted information. No confidence interval should be inferred from the enrollment count alone.

What can a single-group change estimate establish?

The study is listed as a single-group model, with no masking and no allocation to a comparator. A within-group change can summarize what happened to the outcome scores over time in the observed participants. In general, it does not isolate the effect of an intervention from other reasons scores might change. Without a control group, there is no direct between-group estimate to account for time trends, changes in participants' circumstances, or other influences on measured pain. This is why an observed before-and-after change and a treatment effect relative to a comparator are different statistical quantities.

The registry's note that the arms are not a like-for-like control comparison reinforces this point. The primary endpoint description specifies change from baseline, but does not report whether any adjustment beyond that change score was used. The statistical analysis plan, including the handling of covariates or repeated measurements, is not reported in the registry record.

What do planning illustrations mean?

The planning assumptions describe illustrations based on the observed effect, rather than the study's own design justification. They specify a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation; the effect to detect is described as a stated fraction of the observed effect. These assumptions do not make this single-group study a two-arm comparison. Nor do they show that the original study was designed with those assumptions. The protocol's sample-size justification is not reported in the registry record.

In general, sample-size calculations estimate how many participants a hypothetical design would need to detect a specified effect under stated assumptions. They are planning illustrations, not observed power and not evidence that a result is statistically significant. Since the numerical observed effect and the resulting planning estimates are not given in the registry record, no numerical sample-size conclusion can be drawn from those assumptions.

Why does variation matter?

Standard deviation is useful for describing variability in a continuous endpoint. In general, if data are unusually dispersed or do not fit the assumptions of a chosen model, a simple normal approximation may not adequately describe uncertainty. Over-dispersion is a concern when observed variability exceeds what a model expects; methods that account for it may then be needed. The registry record does not report evidence of over-dispersion, distributional checks, or a method for addressing it. It would therefore be speculative to claim that a particular model assumption was met or violated.

The outcome list also includes measures that are not all continuous means, such as a responder index and the number not using rescue medication. Different outcome types generally call for different summaries and analysis methods. The record does not describe the methods used for the secondary outcomes. In the absence of reported analysis details and numerical results, the endpoint definitions can be explained, but the statistical execution and resulting estimates cannot be independently appraised.

10. Confidence Intervals for Each Arm

No two-arm comparison is shown for this trial, but each arm's mean can be given with a t-based 95% confidence interval computed from the posted mean, spread and number of participants.

R code and output

arm <- c("Monovisc")
n   <- c(25)
m   <- c(-3.68)
sp  <- c(2.87)
sd  <- sp      # posted standard deviations
for (i in seq_along(n)) {
  se <- sd[i] / sqrt(n[i]); h <- qt(0.975, n[i] - 1) * se
  cat(sprintf("CARM|%s|%d|%.3f|%.3f|%.3f|%.3f\n", arm[i], n[i], m[i], sd[i], m[i] - h, m[i] + h))
}

CARM  Monovisc  25  -3.680  2.870  -4.865  -2.495

11. Multiplicity, Missing Data and Analysis Populations

The registry lists five outcome measures and identifies a primary endpoint alongside secondary outcomes. It also reports three analyses. The numerical results and a detailed account of how those analyses relate to the outcomes are not reported in the registry record. A prespecified hierarchy, a multiplicity adjustment, or another approach to managing multiple statistical tests is not reported either.

In general, when several outcomes or comparisons are tested, the chance of at least one apparently unusual result can increase if each test is interpreted separately. A prespecified primary endpoint can help distinguish the central question from supporting outcomes, while multiplicity methods can address the interpretation of a family of tests. The registry information does not establish whether such methods were planned or used, so no claim about control of multiplicity is warranted.

Missing-data methods are also not described. The record does not report the number of participants with primary endpoint measurements at baseline or 6 months, reasons for missing measurements, or how missing values were handled. ITT is named as the primary population, but that label alone does not specify the analysis set's operational definition or the method used when an outcome is unavailable. The registry record does not report sensitivity analyses for missing data.

These omissions matter because missing observations and multiple outcomes can affect how precise and robust a result appears. Without participant flow, outcome completeness, and analysis details, it is not possible to assess whether the reported population matched the intended ITT population or how much missingness may have influenced estimates. Since the primary numerical result itself is not reported in the registry record, neither missing-data handling nor multiplicity procedures can be connected to a particular estimate or inference.

12. 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 1% reporting threshold.

Most frequent non-serious adverse event terms

The registry records 25 participants at risk for serious adverse events, with 0 participants affected and 0 deaths. It records 25 participants at risk for other adverse events, with 9 participants affected. No serious adverse event terms are listed in the registry record.

These are counts for the Monovisc group. They do not provide a comparison with another treatment or an untreated group, and they should not be interpreted as comparative risk estimates. The record does not describe event severity beyond the serious-versus-other categories in these figures, nor does it list the specific other adverse event terms. The counts therefore do not show what kinds of other events were recorded or how they were judged related to treatment.

In general, safety counts are interpreted in light of how events were defined, collected, and followed, as well as the number of participants and duration of observation. The registry information does not report further detail about those procedures. The figures describe the posted safety counts, but they do not establish that no unrecorded events occurred or that the observed counts would be the same in a larger or different group.

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

The registry record establishes that a prospective, single-group study evaluated one injection of MONOVISC for hip osteoarthritis, with walking-related NRS pain change from baseline to 6 months identified as the primary outcome. It defines how the scale is interpreted and identifies the ITT population and summary approach. It also reports a group enrollment of 25 and some safety counts.

It does not report the numerical primary outcome result. Therefore, the size and direction of the observed mean change, and the precision of that estimate, cannot be stated from the registry record. The registry's definition that a larger negative change indicates less pain is a rule for interpreting a result, not evidence that such a change was observed. Numerical results for the listed secondary outcomes are also not reported.

Even if a within-group mean change were available, the single-group design would limit interpretation. It would describe change among participants in the study, not the difference between injection and a control condition. Without a comparator, observed changes cannot be separated from other influences on measurement over time. The absence of masking is another design fact, but the registry does not report how outcome measurement or participant expectations were addressed.

The listed safety counts indicate that 0 of 25 participants were recorded as affected by serious adverse events, 9 of 25 were recorded as affected by other adverse events, and 0 deaths were recorded. Those figures are descriptive and do not compare safety with another group. Specific other event terms are not reported in the registry record.

In general, a complete interpretation would consider numerical effect estimates, uncertainty, missing data, analysis methods, and the design's capacity to support comparisons. Several of those details are not reported in the registry record. The available information supports a description of the registered question and design, but not a conclusion about the magnitude or precision of the primary outcome or a comparative treatment effect.

14. Why This Trial Matters Statistically

This study is statistically informative as an example of why outcome definitions and study design must be read together. The registry specifies a focused primary measure—mean change in walking-related hip pain—and gives the scale anchors, direction of interpretation, follow-up period, and target population. Those details identify what the study intended to measure and how a numerical change would be interpreted.

At the same time, a clear endpoint definition is not a substitute for a reported estimate. The primary result, dispersion, and uncertainty are not reported in the registry record. Readers therefore cannot judge the observed magnitude or precision of the pain change from the registered information. The contrast between a detailed outcome definition and an absent numerical result is a useful reminder that endpoint registration and results reporting serve different purposes.

The single-group structure is also important. A before-and-after description can be useful for characterizing a cohort, but it does not supply a controlled comparison. The registry explicitly notes that the arms are not a like-for-like control comparison. This distinction prevents within-group change from being treated as a direct estimate of comparative benefit or harm.

Finally, the record illustrates the importance of reporting analysis populations, missing-data handling, outcome-specific methods, and safety definitions in enough detail to assess results. ITT is named, but implementation details are not reported. The study lists several outcomes and analyses, while the analysis plan and numerical secondary results are absent from the registry record. Statistically, these gaps limit both reproducibility and the extent to which readers can evaluate the evidence. The study remains useful for understanding the registered clinical question and design, while its posted information leaves key result-level questions unanswered.

15. 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 registry record leaves important details unavailable for interpreting this particular study. Although the study is marked completed, numerical results for the primary NRS outcome are not reported in the registry record. The record does not give the mean change, standard deviation, confidence interval, or p-value. Numerical secondary outcome results are not reported either. This prevents evaluation of the magnitude, variability, or precision of measured outcomes.

The single-group design provides no separate comparator. As a result, observed change over time would not, by itself, distinguish intervention-associated change from other influences. Allocation is listed as NA and masking as none; the registry does not describe additional measures to limit bias in outcome assessment. The record identifies a primary ITT population but does not explain its operational definition or report how many participants contributed measurements at the relevant time points.

Other limitations concern reporting detail. The registry does not report the sample-size justification, full statistical analysis plan, interim analyses, multiplicity approach, missing-data methods, or sensitivity analyses. It lists three analyses but does not describe their methods. The names of specific other adverse events are not reported, and details on event collection and follow-up are not given in the safety figures.

The record's purpose is described as obtaining real-world, post-market information, but further details about recruitment, eligibility criteria, setting, and participant characteristics are not included in the registry record recorded. Those omissions restrict assessment of how broadly the enrolled group represents people with hip osteoarthritis. These limitations are specific to what the registry record reports; they do not establish that procedures or analyses were absent from study documents outside the record.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: MONOVISC for Hip Joint Pain Relief Due to Osteoarthritis — NCT04204083.
• Registry record last updated 2025-01-28; status last verified 2025-01.
• Results first posted 2025-01-28.
• 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.

19. Record Summary

NCT04204083 is a completed, prospective, single-group study of a single MONOVISC injection into the index hip joint for osteoarthritis-related symptoms. Enrollment was 25. The registry lists no masking, allocation as NA, and an ITT population for the primary outcome.

The primary outcome is mean change in NRS pain on walking from baseline to 6 months. The scale ranges from 0, no pain, to 10, worst pain; a larger negative change is defined as indicating less pain. The numerical primary result and numerical secondary results are not reported in the registry record. The record names the Lequesne Hip Index Score, Patient Global Assessment, OMERACT-OARSI Responder Index, and rescue medication use among its secondary outcomes.

Safety counts record 0 serious adverse events among 25 participants, 9 participants with other adverse events among 25, and 0 deaths. The registry does not report a comparator-group result, detailed statistical methods, or missing-data procedures. The design and outcome question are identifiable, but the posted information does not permit assessment of the primary estimate's magnitude or precision.