LRTI vs Internal Brace for CMC OA: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for LRTI vs Internal Brace for CMC OA (NCT03971188), a randomized na study. The primary outcome is Postoperative Follow-Up Retention Rate.

2. Clinical Question

The clinical comparison is between two surgical approaches for thumb carpometacarpal arthritis: trapeziectomy with Internal Brace stabilization and trapeziectomy with ligament reconstruction and tendon interposition. The trial was designed as a prospective randomized pilot study to inform planning of a definitive randomized trial. Its stated aims include assessing whether randomization and follow-up are feasible, estimating outcome effects and variability for future planning, and characterizing clinical outcomes.

The investigators’ stated hypothesis anticipated superior patient-reported outcomes with Internal Brace at 6 weeks and 3 months, along with an expedited return to work or activity. That statement is a hypothesis, not a reported finding. The record does not provide comparative results for patient-reported outcomes, return to work or activity, or the other clinical outcomes described in the study summary. It therefore does not establish whether either operation performed better on those measures.

The primary outcome is titled “Postoperative Follow-Up Retention Rate,” with a timeframe of 12 months. Its description refers to determining retention, as well as the proportion of eligible subjects who agree to randomized treatment. The registry lists the unit as thumbs and the measure as a count of units. It does not report the observed retention count, the denominator used to define a rate, or a result for agreement to randomization. The record consequently describes the question and measurement timeframe, but does not answer the primary feasibility question.

3. Trial Design

This is a prospective randomized pilot study with a parallel-group model and no masking. The registry lists the allocation as randomized, the status as completed, and the enrollment as 31. It identifies Washington University School of Medicine as the sponsor. The listed start date is 2020-01-01, and the primary completion date is 2023-08-30. The phase is listed as NA.

The two groups are Internal Brace and LRTI. The Internal Brace description specifies an Internal Brace procedure for thumb CMC osteoarthritis. The LRTI group is described as receiving ligament reconstruction and tendon interposition and serving as the control group. The study title and official title describe the comparison as trapeziectomy with ligament reconstruction and tendon interposition versus Internal Brace for surgical treatment of thumb carpometacarpal arthritis.

Random allocation is intended to make treatment assignment independent of participants’ measured and unmeasured characteristics on average, although a pilot study of this size can still have meaningful chance imbalances. The registry does not report how the random sequence was generated, how assignments were concealed before enrollment, or whether any stratification or blocking was used. These design details are not reported in the registry record.

The study is unmasked. Participants and clinical staff may therefore have known which operation was received; the registry does not specify whether outcome assessors were masked. Lack of masking can matter especially for patient-reported outcomes, expectations, treatment preferences, and decisions about work or activity. It does not by itself invalidate a randomized comparison, but it is relevant when interpreting outcomes that can be influenced by awareness of treatment.

The trial is described as a feasibility and pilot grant application intended to inform planning of a definitive randomized controlled trial. Its stated aims include determining the proportion of eligible subjects who agree to randomization, determining follow-up retention, estimating effect sizes and variability, and characterizing clinical outcomes. The registry lists 16 outcome measures, including measures of thumb range of motion. The record does not provide a detailed protocol, a sample-size justification, or the methods used to execute randomization.

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: Forty-one patients (42 thumbs) agreed to randomization out of a total of 51 patients (52 thumbs) offered participation. One patient had staged bilateral thumb CMC OA surgery one year apart. Ten patients who initially consented to participate subsequently declined; seven decided against randomization and three elected to forego surgery and continue nonsurgical management. A total of 31 patients (32 thumbs) were randomized out of 51 patients (52 thumbs) offered participation.

Overall Study

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 Postoperative Follow-Up Retention Rate, measured over 12 months.

The primary outcome is postoperative follow-up retention rate, assessed at 12 months. Retention is a feasibility measure: it describes whether participants remain available for follow-up, which is important when deciding whether a larger randomized study can collect its planned outcomes. If many participants cannot be reached or do not complete follow-up, later outcome comparisons may be less precise and more vulnerable to bias, particularly if missingness differs between treatment groups or relates to participants’ outcomes.

The registry’s description also refers to the proportion of eligible subjects who agree to randomized treatment. That is another feasibility question, but the record does not state a separate result for it. The listed primary measure is a count of units, with thumbs as the unit, while the outcome title uses the term “rate.” A rate or proportion requires a defined numerator and denominator; neither an observed count nor the denominator is reported. The record therefore does not show the retention result or establish how the rate was calculated.

Retention is used to assess whether follow-up for a future definitive trial may be practicable, rather than to measure a direct clinical benefit of either operation. The outcome should not be read as a comparison of surgical effectiveness. The posted registry record does not report an estimate, uncertainty interval, or between-group test for this primary outcome.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

Clinical trial results are easiest to interpret when the design, outcome definition, analysis population, and uncertainty are all clear. The registry describes this study as prospective, randomized, parallel, and unmasked. These features identify the broad structure of the comparison, but they do not provide the detailed analysis plan or results needed to estimate a treatment effect.

What does randomization contribute?

In general, randomization assigns treatment by chance rather than by clinician or participant choice. This can reduce systematic differences between groups at the start of a study and supports a causal interpretation of a properly conducted comparison. It does not guarantee that groups will be identical, especially in a pilot study. Chance imbalances can occur, and their importance depends on what was measured, how outcomes were collected, and how results were analyzed. The registry does not describe the random sequence, allocation concealment, or any balancing procedures, so those implementation details cannot be assessed from the record.

The study uses a parallel-group design: participants are assigned to a treatment group and the groups are followed over time. The registry lists no masking. In general, awareness of treatment assignment may affect expectations, reporting of symptoms, follow-up behavior, and some clinical decisions. This concern is particularly relevant to patient-reported outcomes. The record does not state whether outcome assessors were masked, so that aspect cannot be evaluated.

What does the primary measure capture?

Follow-up retention is a feasibility outcome, not a measure of whether a procedure improves symptoms or function. It asks whether participants remain available for assessment at the planned follow-up. Retention matters because incomplete follow-up can reduce information and can bias comparisons if the chance of missing data depends on treatment assignment or outcome experience.

The primary outcome is titled “Postoperative Follow-Up Retention Rate,” and its timeframe is 12 months. The registry describes the unit as thumbs and the parameter as a count of units. Its narrative description also refers to the proportion of eligible subjects who agree to randomized treatment. A count and a proportion are different summaries: a proportion requires a numerator and a denominator, and those definitions are not reported. No observed primary-outcome value is listed, so neither the retention level nor a comparison of retention between groups can be interpreted.

How should confidence intervals and tests be understood?

In general, a confidence interval expresses the range of values reasonably compatible with the observed data under the assumptions of the analysis. A narrow interval indicates greater precision, while a wide interval indicates substantial uncertainty. A p-value, when used, summarizes how incompatible the observed data are with a specified null hypothesis under the statistical model; it does not measure the probability that a treatment works or that the null hypothesis is true. Neither a confidence interval nor a p-value for a clinical comparison is reported in the registry record.

For event counts and other outcomes with limited observations, uncertainty can be considerable. A small observed difference does not necessarily indicate equivalence, and a large-looking difference can be unstable. In general, conclusions should consider the effect estimate and its uncertainty, not just whether a test crosses a significance threshold. Here, no comparative outcome estimates or uncertainty intervals are available for the primary retention measure or clinical outcomes.

What is known about planning assumptions?

The record describes planning illustrations 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. For time-to-event tables, the planning quantity is the total number of events using the Schoenfeld method; for other outcomes, it is participants per arm. These are planning assumptions, not observed-power estimates and not evidence of a treatment effect. The resulting sample-size values are not reported in the registry record, and the record does not provide the underlying observed effect or its variability.

Planning calculations based on a pilot estimate require caution in general. Pilot estimates may be imprecise, and a future definitive study may select a different clinically relevant effect or outcome. Sample-size planning should not be mistaken for a finding about the probability that a result is significant. The record does not report the definitive trial’s target enrollment or a formal sample-size justification for this pilot.

How do event data differ from clinical comparisons?

Adverse-event summaries are descriptive counts. Their interpretation depends on how events were defined, whether multiple events in one participant could be counted, how severity and relatedness were assessed, and how long participants were observed. Those details are not fully reported. The serious and other event counts therefore provide a limited safety description, not a complete comparison of harms. In general, rare or infrequent events are difficult to compare precisely without adequate follow-up and uncertainty estimates.

The registry lists 16 outcome measures and no analysis entries. This means the record does not supply results for the listed outcomes or describe the statistical models used to analyze them. The registry also does not report whether estimates were adjusted for baseline characteristics, how repeated measurements were handled, how missing outcomes were addressed, or whether any analyses were prespecified. Such choices can affect estimates and their uncertainty; they cannot be inferred from the randomized design alone.

10. Multiplicity, Missing Data and Analysis Populations

The registry lists 16 outcome measures, and the study summary describes several clinical domains, including patient-reported outcomes, return to work or activity, thumb range of motion, strength, radiographic outcomes, complications, additional surgery, and cost. When a study assesses many outcomes or time points, the chance of at least one apparently unusual result can increase if each is tested separately. In general, a statistical plan may address this through a hierarchy of outcomes, adjustment for multiple comparisons, or an emphasis on estimation rather than isolated significance tests. The registry does not report a multiplicity strategy.

The record lists no analysis entries. It does not report which outcomes were analyzed, how the primary outcome was prioritized in analysis, whether analyses were prespecified, or whether any outcomes were omitted from reporting. Without those details, readers cannot assess selective reporting or determine how the many listed measures relate to a formal testing plan.

Missing-data methods and analysis populations are also not reported in the registry record. There is no description of how missing follow-up was handled, whether participants were analyzed according to randomized assignment, or whether a per-protocol or other population was used. In general, complete-case analyses can be biased when missingness is related to treatment or outcome, while imputation methods require assumptions about the missing data. The record does not identify an approach or provide information to evaluate those assumptions.

The primary outcome concerns retention, so missing follow-up is itself central to the study question. Yet the observed retention result and its denominator are absent. That prevents assessment of the amount and distribution of missing outcome information and leaves the feasibility aim unresolved in the posted record.

11. Safety Results

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

Deaths

Other (non-serious) adverse events

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

Most frequent serious adverse event terms

Most frequent non-serious adverse event terms

Serious events with the highest arm-level rate: concern for deep surgical site infection (5.9%).

The registry reports serious adverse-event counts of 1 among 17 at risk in the Internal Brace group and 0 among 15 at risk in the LRTI group. Other adverse events are reported as 4 among 17 at risk for Internal Brace and 1 among 15 at risk for LRTI. Deaths are listed as 0 for each group. The registry also lists “Concern for deep surgical site infection” as a serious-event term with a value of 5.9%.

These entries are descriptive counts. They do not establish whether one procedure has a higher or lower risk: the record provides no comparative statistical analysis or uncertainty intervals. The listed term should not be assigned to a particular group based on the information reported. The registry does not describe event timing, duration, severity criteria, relatedness assessments, or whether the counts represent participants with an event or event occurrences. The denominators also differ from the reported enrollment, and the record does not explain that relationship.

In general, safety interpretation depends on definitions, follow-up duration, completeness of reporting, and the number of people exposed. Counts alone cannot show whether a difference is meaningful or attributable to treatment. The reported figures are limited safety information, not a comprehensive account of harms.

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

This trial is a randomized pilot study comparing Internal Brace stabilization with LRTI for thumb carpometacarpal osteoarthritis. Its stated purpose is to inform the planning of a definitive randomized trial, with particular attention to feasibility, follow-up, outcome variability, and clinical outcomes. The record confirms that the study is completed and reports enrollment of 31.

The posted results do not report the primary follow-up retention value, a denominator for a retention rate, or the proportion of eligible people who agreed to randomization. Nor do they report comparative estimates for the patient-reported outcomes, return to work or activity, range of motion, strength, radiographic outcomes, complications, additional surgery, or cost described in the study summary. No treatment-effect estimate, confidence interval, or test result for these outcomes is available. The investigators’ stated hypothesis is therefore not a finding that can be confirmed or rejected from this record.

The adverse-event entries offer a limited descriptive account: counts are listed for serious and other events, deaths are listed as 0 in both groups, and a serious-event term is reported with a value of 5.9%. Those entries are not sufficient to establish a comparative safety effect. The registry does not report details needed to interpret event timing, relatedness, or uncertainty.

In general, a pilot study can help assess recruitment, retention, measurement procedures, and the plausibility of planning assumptions. It is not necessarily designed to provide a precise estimate of clinical benefit or harm. The registry record does not report the results needed to judge those feasibility aims in this study. Therefore, the appropriate conclusion is limited: the design and planned questions are described, but comparative effectiveness and the primary retention result are not available in the posted record. The absence of reported results should not be interpreted as evidence that the treatments are equivalent or that either has an advantage.

13. Why This Trial Matters Statistically

The statistical importance of this study lies in its stated role as a pilot for a definitive randomized comparison. Before a larger trial can produce interpretable clinical estimates, investigators need to know whether eligible participants will accept random assignment, whether follow-up can be maintained, and whether outcomes can be measured with sufficient completeness. The study summary identifies these as central feasibility questions.

Retention is especially relevant because incomplete outcome follow-up can undermine the value of randomization. If missingness differs by assigned procedure or is associated with participants’ experiences, a comparison among those with observed data may no longer represent the groups created by randomization. A retention estimate, with a clearly defined denominator and follow-up window, would help researchers plan procedures to limit missing data. The registry specifies a 12-month timeframe but does not report the retention result or denominator.

A pilot can also inform planning through estimates of outcome variability and effect size. Those estimates are useful for designing a later study, but they are uncertain when based on limited data. The registry describes planning assumptions, including a two-sided significance level of 0.05, equal allocation, and a normal approximation, but does not report the resulting sample-size values or the effect estimates on which they depend. These planning details cannot substitute for observed comparative results.

The trial’s randomized structure is relevant to a future treatment comparison, while its lack of masking is important for interpreting subjective outcomes. A definitive study would need clear outcome definitions, follow-up procedures, and a prespecified analysis strategy. In general, those design choices support transparent interpretation and help distinguish a clinically meaningful estimate from chance variation or missing-data effects.

As recorded, the study raises statistically important feasibility and design questions, but the registry does not provide the outcome results required to answer them. Its significance for readers is therefore methodological rather than a basis for a conclusion about which operation performs better.

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 registry record is incomplete for interpreting the primary outcome. It names postoperative follow-up retention rate and gives a 12-month timeframe, but reports no observed result, denominator, or calculation method. The description also includes agreement to randomized treatment, without a separate result for that feasibility measure. This leaves the main stated feasibility questions unanswered in the posted record.

The record contains no comparative results for the clinical outcomes described in the study summary and no analysis entries. It does not report effect estimates, uncertainty intervals, statistical tests, or details of the analysis population. The listed outcome measures cannot be treated as observed findings. The absence of reported results also prevents assessment of whether outcomes were collected at the planned times or whether any measures were unavailable.

Several design details are not reported, including the method of sequence generation, allocation concealment, masking of outcome assessors, sample-size justification, and statistical analysis plan. The registry does not explain how missing data or multiplicity were handled. These omissions limit evaluation of risk of bias and the appropriateness of any planned comparisons.

The adverse-event denominators are 17 for Internal Brace and 15 for LRTI, while reported enrollment is 31; the record does not reconcile these figures. The safety entries also lack event timing, relatedness, and detailed definitions. The registry’s listing of a serious-event term at 5.9% does not identify a group in the entry. These issues limit interpretation of the safety counts and do not support a precise comparison.

Finally, this is described as a pilot study intended to inform future trial planning, not as a definitive efficacy trial. Even if outcome estimates were available, pilot estimates can be uncertain and should be interpreted with their precision and design limitations in mind. The posted record does not provide enough outcome information to assess comparative clinical effects.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: LRTI vs Internal Brace for CMC OA — NCT03971188.
• Registry record last updated 2025-04-06; status last verified 2025-03.
• Results first posted 2025-04-06.
• 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 identifies a completed, prospective randomized pilot study of Internal Brace stabilization versus LRTI for thumb carpometacarpal osteoarthritis. The model is parallel, masking is none, and enrollment is reported as 31. Washington University School of Medicine is listed as sponsor. The record gives a start date of 2020-01-01 and a primary completion date of 2023-08-30.

The primary outcome is postoperative follow-up retention rate at 12 months, described as a count of thumbs. The registry does not report the observed retention result or its denominator. It lists 16 outcome measures and no analysis entries. Comparative clinical outcomes and the investigators’ anticipated patient-reported and return-to-activity findings are not reported as results.

Safety entries list serious and other adverse-event counts by group and deaths of 0 in each group. The record does not provide the detail or comparative analyses needed to draw conclusions about safety. Overall, the registry describes the trial’s design and aims but does not report the results needed to determine whether the feasibility questions or clinical hypotheses were supported.