Do Generic Volar Locking Plates Provide Similar Outcomes at a Reduced Cost?: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Do Generic Volar Locking Plates Provide Similar Outcomes at a Reduced Cost? (NCT06343467), a randomized na study. The primary outcome is 90-day Reoperation Rate.

2. Clinical Question

The official title describes the study as prospective and randomized. The registry lists a randomized allocation, single masking, and a parallel model. The record does not say who was masked. It also does not explain how the block schedule described in the brief summary was combined with randomized allocation. Those design details matter when interpreting how participants or treatment assignments were selected, but they cannot be resolved from the registry record.

3. Trial Design

The study is titled as a prospective randomized comparison of generic and conventional volar locking plates for distal radius fractures. The registry identifies randomized allocation and a parallel model. The brief summary describes a monthly block schedule in which implant type changes at the health system's facilities, while the intervention descriptions identify individual participants as receiving one of the two implant types. The record does not explain how these descriptions relate to one another. The masking designation is single, but which people were masked is not reported in the registry record.

The registry lists enrollment as 101 and status as completed. The listed study start is 2022-11-01, with primary completion on 2023-04-30. For the primary endpoint, the posted arm results list 19 participants for generic implants and 47 for conventional implants. The record does not explain the relationship between those reported group sizes and total enrollment. The population field for the primary endpoint is not reported in the registry record. It is therefore not possible to determine from the posted results whether all enrolled participants were included in the primary-outcome analysis, or how any exclusions or unavailable outcome records were handled.

The stated primary endpoint concerns reoperation for any reason within 90 days after surgery. The registry also lists implant cost, tourniquet time, and estimated blood loss as secondary outcomes. The brief summary says complications and reoperations would be monitored through chart review over short and long term, but the posted primary endpoint is specifically limited to reoperation within 90 days. The record does not provide a protocol, detailed statistical analysis plan, sample-size justification, interim-analysis plan, or further information about chart-review procedures. Those elements should not be inferred from the outcome values.

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: Detailed physical examination of patient with radiographic evaluation of distal radius fracture and indication for volar locking plate open reduction and internal fixation. Patients with open fracture observed on physical examination, polytrauma (any other fracture or medical instability), metaphyseal extension of the fracture, age less than 18 years, and fracture pattern not suitable for fixation with volar locking plate were excluded before assignment to groups.

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 90-day Reoperation Rate, measured over Within 90 days postoperatively.

The primary endpoint counts participants who had a reoperation for any reason within 90 days after the date of surgery. It is a binary outcome at the participant level: a person either had a qualifying reoperation during that period or did not. The registry gives the unit as participants and defines the event as reoperation for any reason postoperatively within 90 days.

In general, a time-limited reoperation endpoint can capture a consequential event that may lead to another procedure, while setting a consistent observation window for the comparison. The 90-day window is the one specified by this registry; the investigators' rationale for selecting it is not reported in the registry record. A reoperation count does not, on its own, describe other postoperative complications, recovery, function, or longer-term outcomes. Although the brief summary refers to monitoring complications and reoperations over short and long term, the posted primary endpoint addresses only reoperation within 90 days.

The posted results record zero events in each reported implant group. That is a description of the observed count, not evidence that the underlying event risk is exactly zero. With no observed events, the comparison provides limited information about how the groups might differ in settings where reoperations occur. The registry does not report details about completeness of follow-up, the handling of participants whose 90-day status was unavailable, or the method used to construct the reported interval.

7. Results Posted in the Registry

• Conventional Implant: 0.0% (0/47) versus 0.0% (0/19) on control; risk difference 0.0 percentage points (95% CI 0.0 to 0.0); unadjusted two-proportion z-test p = n/a.

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.

Implant Cost

• 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 deviations.
• Result:
  • Conventional Implant: mean 1,349 versus 702.38 on control; difference 646.23 (95% CI 610.28 to 682.18), standardized effect d = 7.25; z-test p = <0.001.
• Interpretation:
  • The 95% confidence interval excludes no difference, so the mean is statistically higher for Conventional Implant than for the control. This is an unadjusted, secondary comparison, so it is suggestive rather than confirmatory.

Tourniquet Time

• 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 deviations.
• Result:
  • Conventional Implant: mean 45.06 versus 49.05 on control; difference -3.99 (95% CI -13.37 to 5.39), standardized effect d = -0.27; z-test p = 0.405.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between Conventional Implant and the control. The interval gives the range of effects that remain compatible with the data.

Estimated Blood Loss

• 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 deviations.
• Result:
  • Conventional Implant: mean 13.20 versus 13.30 on control; difference -0.10 (95% CI -5.08 to 4.88), standardized effect d = -0.01; z-test p = 0.969.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between Conventional Implant and the control. The interval gives the range of effects that remain compatible with the data.

Across the secondary outcomes, the posted pattern is not uniform. The implant-cost comparison is clearly separated from zero according to its reported interval, while the tourniquet-time and estimated-blood-loss intervals include zero. This pattern suggests that the secondary outcomes do not all provide the same degree or type of evidence. The registry does not report a single combined measure of these outcomes, and they describe distinct aspects of the procedure.

The cost result is relevant to the study's title and objective, but it does not change the interpretation of the primary endpoint. The primary endpoint concerns reoperation within 90 days; implant cost is a separate outcome measured on the day of surgery. A result for cost cannot establish an effect on reoperation, and the absence of observed reoperations does not determine the cost comparison. Likewise, the operative measures do not substitute for longer-term clinical outcomes.

The secondary p-values are unadjusted. In general, when several outcomes are tested, the chance of finding at least one apparently notable result can increase unless the analysis accounts for multiplicity. No adjustment procedure or detailed hierarchy for these outcomes is reported in the registry record. The secondary results should therefore be treated as outcome-specific evidence rather than as a single confirmatory conclusion. The record also does not provide a detailed plan indicating which secondary comparisons were designated as confirmatory.

These endpoints are reported as group means and comparisons, but the registry does not state whether adjustments were made for other variables or how any unavailable observations were handled. The posted patterns are descriptive of the recorded results and should not be extended to unreported outcomes, longer follow-up, or different settings. The secondary findings add context to the primary result, but they do not resolve its limited information about event risk.

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

• Implant Cost
• Tourniquet Time
• Estimated Blood Loss

9. Statistical Interpretation

10. Statistical Methods Explained

The registry presents a binary primary endpoint and continuous secondary endpoints. These outcome types call for different summaries. The primary endpoint counts participants with a qualifying event. The secondary outcomes are reported as means and standard deviations, with comparisons expressed as mean differences. These are descriptions of the posted results; the detailed analysis methods used for the sponsor's analysis are not reported in the registry record.

What does a risk difference describe?

In general, a risk difference compares the proportion of participants with an event in one group with the proportion in another group. A value of 0.0 indicates no difference in the reported event proportions. Here, both groups have zero recorded reoperations, and the registry reports a risk difference of 0.0. Because there are no observed events in either group, the data do not reveal how event risks might differ when events occur. A zero estimate is not proof that the groups have identical underlying risks.

The primary comparison also reports limits of 0.0 and 0.0. A confidence interval is generally used to express the uncertainty around an estimate under a specified statistical method. Its interpretation depends on how it was constructed and on assumptions about the data. The construction method for the primary interval is not reported in the registry record. In this setting, the displayed zero-width interval should not be read as evidence that all plausible differences have been ruled out.

How should mean differences and standard deviations be read?

For a continuous outcome, the registry reports each group's mean and standard deviation, then gives a mean difference comparing conventional with generic implants. A mean difference expresses the contrast on the outcome's original scale: United States Dollars for implant cost, minutes for tourniquet time, and milliliters for estimated blood loss. A positive difference means the conventional-group mean is higher in the posted comparison; a negative difference means it is lower. The standard deviation describes spread among individual observations, rather than uncertainty in the estimated group mean.

A confidence interval around a mean difference gives a range of values compatible with the estimate under the method used. When an interval includes zero, the results do not rule out no mean difference under that interval procedure. That does not show that the groups are equivalent. Conversely, an interval that does not include zero indicates a difference under that method, but does not address the importance of the difference or remove possible bias. The registry does not report the confidence-interval methods or adjusted analyses for these outcomes.

What does an unadjusted p-value convey?

In general, a p-value measures how unusual data at least as incompatible with a specified null hypothesis would be if that hypothesis and the analysis assumptions were true. It is not the probability that the null hypothesis is true, and it does not measure the size or practical importance of an effect. The posted secondary comparisons are labelled unadjusted. Their p-values do not account for testing multiple outcomes, and the registry does not report a multiplicity procedure. The primary endpoint has no posted p-value.

Because the record lists three secondary outcomes, interpreting each result in isolation can overstate the strength of evidence when multiple comparisons are considered. The record does not explain whether the secondary outcomes were prespecified in a detailed plan, whether all planned outcomes are posted, or whether there were additional analyses. The count of analyses recorded in the registry is 0, while summary outcome results and comparisons are posted; the record does not explain that distinction.

What do the planning illustrations mean?

The sample-size illustrations are explicitly planning calculations based on fractions of the observed effect, not the trial's own design justification. Their stated assumptions are a two-sided significance level of 0.05, equal allocation between groups, and a normal approximation. The listed participant counts are per arm for the continuous outcomes. They are hypothetical planning values, not observed sample sizes, not evidence of achieved power, and not a retrospective measure of the trial's ability to detect a difference. The protocol's own sample-size assumptions or justification are not reported in the registry record.

Planning values derived from an observed effect can vary substantially depending on the fraction selected and on the variability in the observed data. They should not be treated as reliable design targets without considering whether the observed effect is a sensible planning assumption. In general, unusually small or large illustrations can reflect the size and variability of the observed contrast under the stated calculation assumptions. They do not change the interpretation of the actual group summaries.

Finally, the registry describes randomized allocation but also describes month-by-month switching of implant type in the brief summary. The relationship between individual randomization and the block schedule is not reported in the registry record. Without further design and analysis information, the extent to which the comparisons account for time, facility practices, or other factors cannot be assessed. No additional modeling, adjustment, interim monitoring, or missing-data method should be presumed.

11. Confidence Intervals and Precision

Precision concerns the range of values that remain compatible with an estimate under the method used. For the primary risk difference, the registry reports an estimate of 0.0 and limits of 0.0 and 0.0. Both groups also have zero recorded reoperations. Since the record does not report how this interval was constructed, its zero-width form should not be interpreted as demonstrating that uncertainty is absent. With no observed primary events, the reported data provide little basis for estimating a difference in event risk.

For implant cost, the reported mean difference is 646.2 United States Dollars, with limits from 610.3 to 682.2. That interval does not include zero and is relatively narrow around the reported contrast. The interpretation remains conditional on the analysis and data as recorded; the registry does not report an adjusted analysis or the interval method. The estimate is a comparison of group means, not a guarantee of the cost difference in every setting.

For tourniquet time, the reported mean difference is -3.99 minutes, with limits from -13.37 to 5.391. For estimated blood loss, the mean difference is -0.1 milliliters, with limits from -5.081 to 4.881. Both intervals include zero and span values on either side of no mean difference. This indicates uncertainty about the direction and size of the differences under the reported interval procedure; it does not establish equivalence. No equivalence margin is reported.

Confidence intervals quantify sampling uncertainty under the assumptions of their method; they do not account automatically for bias, incomplete outcome recording, or differences in how treatment was assigned. The registry does not describe follow-up completeness or missing-data handling. Therefore, precision should be considered alongside the reported group counts and the unresolved relationship between those counts and enrollment.

12. Multiplicity, Missing Data and Analysis Populations

The record lists one primary endpoint and three secondary outcomes. It reports outcome summaries and comparisons, but no detailed statistical analysis plan. The number of analyses recorded in the registry is 0, even though comparisons are posted; the reason for this difference is not reported in the registry record. There is no reported multiplicity adjustment, testing hierarchy, or statement about whether the secondary outcomes were intended to be confirmatory.

Multiplicity matters because examining several outcomes creates more opportunities for a nominally notable result to arise by chance. The secondary p-values are explicitly unadjusted. They can be read as outcome-specific summaries under their respective null hypotheses, but should not be treated as if the set of comparisons had a reported family-wise error control strategy. The primary outcome's zero event count and lack of a posted p-value are separate from that issue.

Missing-data handling and analysis populations are also not described in sufficient detail. Total enrollment is 101, whereas the primary-outcome arm results report 19 and 47 participants. The relationship between those counts and enrollment is not reported in the registry record. The primary endpoint's population is not specified, and the record does not state whether every participant had complete 90-day follow-up, whether exclusions occurred, or how unavailable records were handled. The corresponding details for secondary endpoints are not fully described beyond their reported group summaries.

The brief summary says chart review will be used to monitor complications and reoperations, but it does not give details about review procedures or completeness. No interim-analysis plan or stopping rule is reported in the registry record. These omissions do not show that a particular method was or was not used; they limit what can be concluded about analysis choices and data completeness from the posted information.

13. 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 adverse-event figures report zero serious adverse events among 19 participants at risk in the generic implant group and zero among 47 participants at risk in the conventional implant group. The figures also report zero other adverse events in each group and zero deaths in each group. These are event counts in the registry record, not proof that such events cannot occur or that the groups have identical safety profiles.

Zero observed events can be difficult to interpret, especially when the reported groups are limited in size and follow-up details are not described. The adverse-event record does not list serious adverse-event terms. It also does not describe the method for collecting or adjudicating these events, or whether follow-up was complete for all participants. The primary endpoint is a 90-day reoperation measure, while the brief summary refers more broadly to complication monitoring; the registry does not establish that the adverse-event figures cover the same event definitions or observation period as the primary endpoint.

Accordingly, these figures are best read as no events recorded in the listed categories for the reported groups. They should not be generalized to unreported time periods or interpreted as evidence of no safety risk.

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

The primary result establishes a narrow factual point: the registry reports no 90-day reoperations in either of the two posted outcome groups. The reported risk difference is 0.0. This does not establish that the implant strategies are equivalent, that one is as safe as the other, or that the true reoperation risk is zero. Equivalence requires a defined margin and an analysis designed to assess whether differences fall within that margin; neither is reported in the registry record.

The secondary results provide separate information about cost and operative measures. In particular, the posted cost comparison shows a difference in group means with an interval that excludes zero. This result is not interchangeable with the primary clinical endpoint, and it does not show that cost differences lead to any difference in reoperation. The other secondary comparisons have intervals that include zero, which is not the same as demonstrating no meaningful difference.

Randomized allocation is listed, but the brief summary's description of month-based switching is not reconciled with the individual-level arm descriptions. Without further information, the way assignment operated in practice and the possible role of time or facility practices cannot be determined. Likewise, the reported outcome group counts are not reconciled with overall enrollment, and completeness of follow-up is not described. These uncertainties limit the strength and scope of interpretation.

The findings apply to the outcomes and observation periods that are actually reported. They do not establish results for longer-term reoperations, complications beyond the posted adverse-event figures, functional outcomes, or other patient-important measures. The record's completed status indicates the study is listed as completed; it does not by itself make the posted evidence definitive. The results are informative descriptions of the recorded groups, with important limits on what they can establish.

15. Why This Trial Matters Statistically

This trial is statistically interesting because its primary endpoint is a binary event that did not occur in either reported group, while its secondary outcomes include continuous measures with different patterns of precision. The contrast illustrates why an estimate alone is not enough: a zero estimated difference for a rare or unobserved event can coexist with substantial uncertainty about underlying risk. The interval printed for the primary result needs cautious interpretation because its construction method is not reported.

The study also makes a useful distinction between clinical and resource-related outcomes. Reoperation within 90 days and implant cost answer different questions. A precise cost comparison does not automatically make the clinical comparison precise, and the absence of observed reoperations cannot establish equality in clinical outcomes. Reading each endpoint according to its scale and purpose prevents one result from being used as a substitute for another.

The registry record also shows why design and reporting details matter to statistical interpretation. Randomized allocation is listed, yet the brief summary describes month-based switching. The relationship between these descriptions is not explained. In addition, total enrollment and the posted primary-outcome group sizes are not reconciled, and the record does not describe missing-data handling, an analysis population, or a detailed multiplicity plan. Such gaps do not determine the direction of any bias, but they constrain how confidently the comparisons can be interpreted.

Finally, the planning illustrations are based on observed effects and stated assumptions, rather than documenting the trial's original sample-size justification. They should not be mistaken for observed power or evidence that the completed study was adequately sized for every endpoint. Together, these features make the study a clear example of separating observed results, uncertainty, design information, and conclusions that the registry record does not support.

16. Limitations

• The posted summary statistics are the only data these results rest on; patient-level data, full protocols and statistical analysis plans are not available.
• Recalculated results are simple, unadjusted calculations from posted summaries. They do not replace the sponsor's prespecified analysis.

Several limitations specific to this study affect interpretation. The registry lists randomized allocation, but the brief summary describes a block schedule in which implant type changes by month. The relationship between this schedule and the participant-level arm descriptions is not reported in the registry record. If assignment or practice patterns varied over time, the record does not explain how that was addressed in the comparisons.

The registry gives total enrollment as 101, but the posted primary-outcome groups list 19 and 47 participants. The relationship between those numbers is not explained. The primary population is not specified, and the record does not report whether follow-up was complete for the 90-day endpoint or how missing observations and exclusions were handled. These limits make it difficult to assess the completeness of the primary comparison.

The primary event was absent in both reported groups, leaving little observed information about differences in reoperation risk. The reported interval has identical limits, but its construction method is not reported. The record also provides no equivalence margin, so the result cannot establish equivalence. The adverse-event figures likewise report no events, with no detailed information about event ascertainment or follow-up coverage.

For the secondary outcomes, comparisons are unadjusted and no multiplicity strategy is reported. The registry does not provide the protocol's sample-size justification, interim-analysis plan, detailed statistical analysis plan, or adjustments for other variables. It also does not identify who was masked despite listing single masking. These are limits on assessment of the posted evidence, not proof that specific methods were omitted in practice.

17. Related Tutorials

18. Related Statistical Calculators

19. Sources

• ClinicalTrials.gov: Do Generic Volar Locking Plates Provide Similar Outcomes at a Reduced Cost? — NCT06343467.
• Registry record last updated 2024-08-28; status last verified 2024-03.
• Results first posted 2024-08-28.
• 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.

20. Record Summary

The registry describes a completed, prospective randomized study of generic versus conventional volar locking plates for distal radius fractures. It lists a parallel model and single masking, without specifying who was masked. Total enrollment is 101. The primary outcome is reoperation for any reason within 90 days after surgery; the posted results report zero events in each outcome group, with 19 participants in the generic group and 47 in the conventional group.

Three secondary outcomes are listed: implant cost, tourniquet time, and estimated blood loss. The posted cost comparison has an interval above zero, while the intervals for the operative measures include zero. The secondary comparisons are unadjusted. The relationship between total enrollment and reported outcome group sizes, the detailed analysis plan, missing-data handling, and the interval methods are not reported in the registry record. The record's brief summary also describes month-based switching of implant type without explaining how that relates to randomized allocation.