Endoscopic Trigger Finger Release: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Endoscopic Trigger Finger Release (NCT03883477), a non-randomized na study. The primary outcome is Scar Comparison Between Treatment Arms, as Measured by the Patient and Observer Scar Assessment Scale (POSAS).

2. Clinical Question

The study’s stated purpose was to compare recovery, scar, and patient satisfaction after endoscopic release versus standard open surgical treatment. Its primary outcome focuses on scars, assessed with the Patient and Observer Scar Assessment Scale (POSAS). The questionnaire is completed by both the patient and the patient’s surgeon or Physician Assistant (PA-C). It includes 6 items on a 10-point scale, with 1 indicating best and 10 indicating worst. The combined score ranges from 12 to 120; 12 indicates normal skin and 120 indicates the worst scar imaginable.

The study also lists outcomes related to satisfaction, return to work, post-operative therapy, pain medication use, complications, and recurrence. These outcomes provide context for the broader recovery question, but the registry record does not report their results. The central interpretation therefore depends on information not available in the record: the observed POSAS scores at each assessment time, their variability, and the analysis used to compare the groups. Without those results, the registry entry defines the comparison but does not establish whether the groups had similar or different scar scores.

3. Trial Design

This completed study is listed as NCT03883477 and is titled Endoscopic Trigger Finger Release. Cedars-Sinai Medical Center is named as the sponsor. The registry record lists the study phase as NA, the allocation as NON-RANDOMIZED, masking as NONE, and the model as PARALLEL. The study began on 2019-03-13, reached primary completion on 2021-09-24, and has status COMPLETED.

The parallel design assigns participants to one of two treatment groups, but the non-randomized allocation means assignment was not by chance. The arm descriptions state that 12 patients recommended for surgical treatment would undergo endoscopic release and 12 would undergo standard open surgical release. The record separately reports enrollment of 26. It does not explain the difference between the enrollment figure and the numbers in the arm descriptions. Safety figures list 13 at risk in each group; the record does not reconcile those figures with its other enrollment and arm information.

Because allocation was non-randomized, differences between groups could reflect characteristics that influenced treatment selection as well as any difference associated with the procedures. The registry record does not report how treatment was selected, whether groups were matched or adjusted for baseline characteristics, or what characteristics were measured. A non-randomized comparison can describe observed outcomes, but it cannot, on its own, separate treatment effects from these possible group differences.

The record lists 7 outcome measures and 9 analyses. It identifies a continuous primary outcome summarized using means and standard deviations. The planned assessment times are 1 Week, 1 Month and 6 Months after surgery. The record does not describe the statistical tests or models used for the primary comparison, nor does it report whether there were planned interim analyses or a sample-size justification. Those details are not reported in the registry record.

4. Participant Flow and Accounting

The registry reports how participants moved through each stage of the study. All counts below are exactly as posted; missing counts are not inferred from other stages.

Overall Study

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: One patient in the Endoscopic Release group died from causes unrelated to the study and one patient in the Standard Open Release treatment arm did not complete the first post-operative survey. All subjects were included in the final statistical 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 Scar Comparison Between Treatment Arms, as Measured by the Patient and Observer Scar Assessment Scale (POSAS), measured over 1 Week, 1 Month and 6 Months after surgery.

The primary endpoint is the scar comparison between treatment groups, measured with the Patient and Observer Scar Assessment Scale (POSAS). Both the patient and the patient’s surgeon or Physician Assistant (PA-C) complete questionnaires. The instrument has 6 items on a 10-point scale, where 1 is best and 10 is worst. The total score ranges from 12 to 120, with 12 indicating normal skin and 120 indicating the worst scar imaginable. Scores are intended to capture how the scar is viewed by both the patient and a clinician, rather than relying on a single observer’s assessment.

The endpoint is assessed at 1 Week, 1 Month and 6 Months after surgery. Repeated assessments can describe how scar ratings change over time, although the registry record does not report the scores or the method used to compare the groups across assessment times. The primary outcome is described as a mean with standard deviation. A mean summarizes the group’s average score, while the standard deviation describes the spread of individual scores around that average. Neither summary alone shows the full range or distribution of scores.

The endpoint is relevant to the stated purpose because scar appearance and perception are among the features the study set out to compare. Its meaning depends on the observed scores, the completeness of assessments, and how patient and clinician ratings were combined or analyzed. The registry record does not report those results or clarify whether patient and clinician scores were analyzed separately. Consequently, the endpoint definition is available, but its observed comparative result is not reported in the registry record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The registry record identifies the primary measure as continuous and says it is summarized by a mean and standard deviation. The mean is the arithmetic average of the observed scores in a group. The standard deviation describes how dispersed those scores are around the group mean. In general, a mean provides a compact summary of a group, but it can hide variation among individuals and does not show the shape of the score distribution. A standard deviation gives information about spread, but it does not by itself indicate uncertainty in the estimated mean or the treatment comparison.

For a comparison between two groups, the group means need to be considered together with an estimate of their contrast and its uncertainty. A confidence interval is a statistical range that expresses uncertainty around an estimated quantity under the assumptions of the analysis. A narrow interval indicates greater precision than a wide interval, while the location of the interval indicates which values remain compatible with the data and method. The registry record does not report a confidence interval for the primary comparison, so the precision of any group difference cannot be assessed from the entry.

What does a mean summarize?

For POSAS, a mean would summarize the average score among the observations included in a group at a particular assessment. Because lower scores indicate better scar ratings on the described scale, the direction of a mean contrast would need to be interpreted with that scoring convention in mind. This is a general explanation of the scale, not a statement about the study’s observed scores. The registry record does not report the means at 1 Week, 1 Month or 6 Months.

Repeated assessment times raise a further method question. The same participant may contribute scores at more than one time point, so observations over time can be related rather than independent. In general, a repeated-measures approach can account for that relationship, while separate comparisons at each time point answer a different set of questions. The registry record names the assessment times but does not report whether the analysis used separate comparisons, a repeated-measures model, or another method. It also does not report how patient and clinician ratings were represented in the analysis.

Why does allocation matter?

Random allocation, when used, is intended to make treatment groups comparable on average with respect to measured and unmeasured characteristics. This study is listed as NON-RANDOMIZED, so that protection cannot be assumed. In general, treatment selection may be related to participant characteristics that also influence outcomes. This can create confounding: an observed group difference may reflect both the treatment and differences between the people receiving each treatment. Adjustment for measured characteristics can sometimes address part of this concern, but cannot guarantee removal of confounding, especially from characteristics that were not measured. The registry record does not report the selection process, baseline comparisons, or any adjustment strategy.

Masking is listed as NONE. In general, knowledge of treatment can influence subjective assessments, including ratings of a scar. The POSAS includes both patient and clinician assessment, so the possibility of expectation-related influence is relevant to interpretation. This design fact does not show that ratings were biased; it indicates that interpretation should account for the absence of masking. The registry record does not describe any procedures intended to limit such influence.

What does a p-value tell the reader?

A p-value, when reported, describes how unusual the observed data or a more extreme result would be under a specified statistical model and a null hypothesis. It is not the probability that the null hypothesis is true, and it does not measure the size or practical importance of an effect. A p-value should be interpreted alongside an effect estimate, its uncertainty, the design, and the quality of the data. The registry record does not report a p-value for the primary outcome, so no significance interpretation can be made from the entry.

Confidence intervals are also useful because they show a range of estimates compatible with the observed data and analytic assumptions. They can reveal whether the data are consistent with a range of potentially important differences or are more precise around a narrower range. They do not correct for non-randomized allocation, missing data, measurement concerns, or selective reporting. No confidence interval for the primary outcome is reported in the registry record.

How should the planning illustration be understood?

The record describes a planning illustration based on an observed effect, with a two-sided significance level of 0.05, equal allocation, and a normal approximation. It says the effect to detect is a stated fraction of the observed effect. Such calculations are hypothetical planning exercises: they ask how many participants per arm might be needed under the stated assumptions to detect a chosen effect with a specified power. They do not describe the number of participants actually analyzed, and they are not observed power. The record does not report the calculated planning values in the information available for interpretation here, so no sample-size figure can be stated.

In general, a planning calculation depends on assumptions about the effect size, variability, type I error, power, allocation, and analysis method. If any assumption differs from the eventual study conditions, the illustration may not describe the sample size needed for a future study. A planning calculation based on an observed effect can also be unstable when that effect estimate is uncertain. The registry record does not report the original design justification or explain how the illustration relates to the study’s enrollment.

For count outcomes, variation may exceed what a simple model assumes; this is called over-dispersion. In general, allowing for over-dispersion can produce more realistic uncertainty when counts vary more than expected under a simpler model. That concept is not evidence that over-dispersion was present or modeled in this study. The registry record does not describe the analysis method for the listed count-related outcomes, such as complications or recurrence.

10. Multiplicity, Missing Data and Analysis Populations

The registry record lists 7 outcome measures and 9 analyses. When a study examines multiple outcomes, time points, or comparisons, the chance of finding at least one apparently unusual result can increase if each analysis is treated as a separate confirmatory test. General approaches to multiplicity include identifying one primary comparison in advance, adjusting the threshold for multiple tests, or clearly labeling additional analyses as exploratory. The record identifies a primary scar outcome but does not report whether or how multiplicity was addressed across the listed outcomes, assessment times, and analyses.

The primary outcome is scheduled at 1 Week, 1 Month and 6 Months after surgery. The registry record does not say whether one time point was designated as the main comparison, whether all time points were treated as co-primary, or whether a joint analysis was used. It also does not state whether patient and clinician ratings were analyzed separately or together. These choices affect what a reported comparison would mean, and the record does not report them.

For missing data, the registry record notes that one patient in the Endoscopic Release group died from causes unrelated to the study and one patient in the Standard Open Release group did not complete the first post-operative survey. It further states that all subjects were included in the final statistical analysis. The record does not explain which outcome observations were available after these events, how missing POSAS scores were handled, or whether the analysis used assumptions about the reasons for missingness. Inclusion in the final analysis does not specify the method used for absent observations.

The analysis populations are also not described in detail. The registry record does not clarify whether all enrolled participants were analyzed according to their original group, only participants with observed outcome data were included for each assessment, or another population definition was used. It does not report sensitivity analyses for missing data. These omissions limit the ability to judge whether the analyzed data represent the intended groups and how robust a result would be to different assumptions.

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 record reports 0 serious adverse events among 13 at risk in Endoscopic Release and 0 among 13 at risk in Standard Open Release. It also reports 0 other adverse events among 13 at risk in each group. These are the recorded event counts and denominators; they do not establish that no event could occur, nor do they establish equivalent safety between the groups. The record does not report the definitions used for serious and other adverse events or the method for collecting and classifying them.

The deaths field reports 1 death in Endoscopic Release and 0 in Standard Open Release. The primary outcome description says that one patient in the Endoscopic Release group died from causes unrelated to the study. A death recorded in the group data should not automatically be interpreted as treatment-related; the registry record describes this death as unrelated to the study. The record does not provide further details for the death.

The safety denominators differ from the 12 patients described in each arm and from the overall enrollment of 26. The registry record does not explain that discrepancy. No serious adverse event terms are listed. These figures should therefore be read as registry-reported counts with their stated denominators, not as a complete account of every possible safety concern or as a basis for causal comparison.

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

The record establishes that a completed, non-randomized, parallel-group study was designed to compare endoscopic and standard open trigger finger release. It defines a primary scar outcome assessed with POSAS at 1 Week, 1 Month and 6 Months after surgery. It also lists other recovery-related outcomes. Those details clarify what the study set out to measure, but they do not show the results of those measurements.

Because the registry record does not report POSAS means, standard deviations, comparative estimates, confidence intervals, or p-values, it cannot show whether scar ratings favored either group, how large any difference was, or how precisely a difference was estimated. It also cannot establish that the groups had the same outcomes. Lack of reported results is not evidence of no difference; it is a limit on what can be concluded from this registry entry.

The non-randomized allocation matters because treatment groups may differ in ways related to outcomes. Masking is listed as none, which is relevant for subjective assessments such as scar ratings. These design features do not prove that bias occurred, but they mean that any observed group contrast would need interpretation in light of possible confounding and assessment effects. The registry record does not report baseline characteristics or adjustment methods that would help evaluate those concerns.

The record says all subjects were included in the final statistical analysis and notes one death in the endoscopic group and one incomplete first post-operative survey in the open group. It does not explain the handling of missing observations. Therefore, the statement about analysis inclusion is not enough to determine how complete the outcome data were or how missingness might affect an estimate.

The listed safety counts are also limited. The record reports no serious or other adverse events in either group using the stated risk denominators, and records one death in the endoscopic group, described elsewhere in the entry as unrelated to the study. The denominators are not reconciled with enrollment and arm descriptions. These entries cannot establish a comparative safety profile. In short, the registry record supports understanding the planned comparison and its limitations, but not a conclusion about whether one procedure produced better scar, recovery, satisfaction, or safety outcomes.

13. Why This Trial Matters Statistically

This study illustrates why the design and outcome definitions matter as much as the comparison being asked. The POSAS outcome combines patient and clinician perspectives and is intended to capture scar ratings over time. Its scale direction is explicit: 1 is best and 10 is worst for each item, and the total ranges from 12 to 120. A reader can understand what a higher or lower score would mean, but cannot judge the observed outcome without the group summaries and an estimate of uncertainty.

The non-randomized design highlights a central issue in clinical comparisons: treatment groups may differ before treatment for reasons related to the choice of procedure. A numerical difference, if reported, would describe the groups as observed; causal interpretation would require considering how treatment selection and baseline differences were addressed. The registry record does not report those details, so the design itself sets an important boundary on interpretation.

The entry also shows why clarity about the analysis population and missing data is important. It notes a death and a missed first post-operative survey, while saying all subjects were included in the final statistical analysis. Without a description of the handling of incomplete scores, that statement cannot be translated into a clear account of which measurements contributed at each assessment.

Finally, the record contains multiple outcome measures and analyses but does not report how multiplicity was handled. A transparent account of primary comparisons, analysis choices, and uncertainty would help readers distinguish confirmatory findings from exploratory patterns. The study is statistically informative as an example of questions that arise when assessing a non-randomized surgical comparison; however, the registry record does not provide outcome results needed to resolve the stated clinical question.

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 most important limitation of the registry record for interpreting this study is that it does not report the primary outcome results. No POSAS group means, standard deviations, treatment contrasts, confidence intervals, or p-values are reported. Results for the listed secondary outcomes are also not reported in the registry record. This prevents assessment of the size, direction, precision, or consistency of any observed differences.

The comparison is non-randomized and unmasked. The record does not describe how participants entered each treatment group, whether baseline characteristics differed, or whether analyses adjusted for those characteristics. Since treatment choice may be associated with other factors that affect recovery or scar assessment, this missing information limits causal interpretation. The record does not state how assessments were conducted to reduce the influence of knowledge of treatment.

There are unresolved differences in the reported group counts. Enrollment is 26, the arm descriptions state 12 patients in each group, and safety figures list 13 at risk in each group. The record does not reconcile these figures. This makes it difficult to connect the study population described for treatment, the safety denominators, and the final analysis population.

The record notes one death in the Endoscopic Release group and one incomplete first post-operative survey in the Standard Open Release group. It says all subjects were included in the final statistical analysis but does not explain how missing outcome measurements were handled, whether data were available at later assessments, or whether any sensitivity analyses were performed. It also does not specify how patient and clinician POSAS ratings were analyzed or how the repeated assessment times were modeled.

Finally, 7 outcome measures and 9 analyses are listed, but the registry record does not describe multiplicity procedures or identify the detailed analysis plan. It does not report the original sample-size justification, interim analyses, or statistical tests used. These omissions restrict evaluation of the analysis choices and the strength of any findings, even apart from the absent outcome results.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Endoscopic Trigger Finger Release — NCT03883477.
• Registry record last updated 2022-05-11; status last verified 2022-04.
• Results first posted 2022-05-11.
• 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

NCT03883477 is a completed, non-randomized, parallel-group study of Endoscopic Release versus Standard Open Release for trigger finger. Cedars-Sinai Medical Center is listed as the sponsor. The study began on 2019-03-13 and reached primary completion on 2021-09-24. Masking is listed as none, and phase as NA.

The primary outcome is scar assessment using POSAS at 1 Week, 1 Month and 6 Months after surgery. The registry record describes patient and clinician questionnaires and a score range from 12 to 120. It lists 7 outcome measures and 9 analyses, but does not report the primary or secondary outcome results. It also does not explain the differences among enrollment of 26, arm descriptions of 12 patients in each group, and safety denominators of 13 at risk in each group.

The record reports 0 serious and 0 other adverse events in each group, and 1 death in Endoscopic Release and 0 in Standard Open Release. The death is described as unrelated to the study. Missing-data handling, detailed statistical methods, and multiplicity procedures are not reported in the registry record.