Non-Surgical Treatment for Rotator-Cuff Tears Using Platelet-Rich-Plasma: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Non-Surgical Treatment for Rotator-Cuff Tears Using Platelet-Rich-Plasma (NCT02246530), a randomized na study. The primary outcome is Diagnostic Ultrasound.

2. Clinical Question

The clinical question concerns a non-surgical approach for partial-thickness tears. The project summary frames the goal as identifying a conservative approach for cases that might otherwise end in surgical correction. That statement describes the study’s motivation, not evidence that either injection avoids surgery or changes the course of a tear.

The registered outcome focuses on ultrasound assessment rather than a patient-reported symptom score. The record describes an initial ultrasound confirming a supraspinatus tendon tear, followed by injection and a planned ultrasound assessment at 6 months. Shoulder Pain and Disability Index is listed among the secondary outcomes. The registry record does not provide the questions, scoring rules, or analysis results for that measure.

The record identifies randomized allocation and lists both injection approaches, but it also labels the model as single group. The relationship between that model label and the listed interventions is not explained. The available record therefore identifies the intended clinical comparison, while leaving important details of the actual analysis and endpoint definition unresolved.

3. Trial Design

The registry identifies this study as randomized, with single masking and a single-group model. It lists PRP injection into a partial-thickness rotator-cuff tear and subacromial steroid bursal injection as interventions. The latter is described as current standard care for resistant partial-thickness tears. Although those entries suggest two treatment approaches, the single-group model label makes the design description internally difficult to reconcile. The method used to generate the random allocation, the allocation ratio, and the identity of the masked parties are not reported in the registry record.

Enrollment is listed as 11. The study status is terminated. Its recorded start is 2014-07 and its primary completion is 2021-01. The reason for termination and whether termination occurred before or after the planned follow-up period are not reported in the registry record. The phase is listed as NA.

The primary outcome is titled Diagnostic Ultrasound, with the unit listed as participants and the time frame as 6 months post procedure. The outcome description says an initial ultrasound image was used to demonstrate a supraspinatus tendon tear, after which participants were assigned to a study arm and proceeded to injection. It also notes that two participants in the PRP group were lost to follow-up and lacked completed six-month ultrasound imaging.

There are four outcome measures listed, including Shoulder Pain and Disability Index entries among the secondary outcomes. No outcome analysis is listed. The record does not report a statistical analysis plan, sample-size justification, planned enrollment by group, or details of follow-up beyond the ultrasound description. Consequently, the design can be described from its registry labels and outcome notes, but the intended statistical comparison cannot be reconstructed fully.

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: Three subjects in this study were enrolled however prior to randomization in to their respective groups, they had a negative diagnostic ultrasound thus they were excluded from the study.

Overall Study

Reasons for not completing this period:

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 Diagnostic Ultrasound, measured over 6 months post procedure.

The primary endpoint is titled Diagnostic Ultrasound. It is expressed as a count of participants, with assessment planned at 6 months post procedure. The description explains that an initial ultrasound was obtained to demonstrate a tear of the supraspinatus tendon, a key rotator-cuff tendon. The stated purpose of the six-month assessment is to compare against baseline for structural changes.

Ultrasound is used in the described study to visualize tendon structure and confirm the tear at baseline. As a general measurement concept, repeating an imaging assessment can provide information about whether the observed structural appearance has changed over follow-up. This is distinct from asking participants to report pain or functional limitations, which are addressed separately by the listed Shoulder Pain and Disability Index outcomes.

The registry record does not define what ultrasound finding would count as improvement, worsening, or no change. It does not describe image-reading procedures, assessor blinding, measurement reliability, or the categories used to turn the image assessment into a participant count. The endpoint is therefore identifiable as a six-month structural imaging outcome, but its exact operational definition is not reported in the registry record. Nor are the observed ultrasound categories or a treatment-group comparison reported. Two PRP-group participants are specifically described as lacking completed six-month ultrasound imaging because they were lost to follow-up.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The registry marks allocation as randomized and masking as single, but does not describe the randomization procedure, concealment, or which participants or study personnel were masked. It also labels the model single group while listing two intervention approaches. Those labels are not enough to determine how the planned comparison was implemented. The statistical methods used for the outcome analysis are not reported in the registry record, and the record lists zero analyses.

What does a participant count represent?

The primary outcome is recorded as a count of participants, and its type is described as a binary outcome. In general, a binary outcome places each participant into one of two categories, such as meeting or not meeting a prespecified criterion. A count then tallies participants in one of those categories. For that count to have a clear interpretation, the registry or analysis plan needs to define the event or response category, its timing, and how uncertain or unclassifiable assessments are handled. The outcome description does not report those criteria for the ultrasound assessment. It says the assessment concerns structural changes relative to baseline, but does not specify the categories that define a counted response.

A participant count alone does not tell readers how often an event occurred unless the relevant denominator and the outcome definition are also clear. The safety record gives denominators for its adverse-event counts, but no such primary-outcome counts or group comparison are reported. As a result, neither a primary-outcome event proportion nor a contrast between groups can be interpreted from the registry record.

What would an estimate and confidence interval add?

As a general statistical explanation, an effect estimate expresses the size and direction of a comparison, while a confidence interval describes the precision of that estimate under the assumptions of the analysis. A narrow interval generally indicates greater precision than a wide one; an interval spanning a range of plausible effects signals that the estimate is uncertain. A p-value, when used, addresses how compatible the observed data are with a specified statistical null model. It does not measure the probability that a treatment works, and it does not express the clinical importance of an effect.

No primary-outcome estimate, confidence interval, or p-value is reported in the registry record. There is therefore no basis for interpreting statistical significance, precision, or the magnitude of an ultrasound difference. Even if an estimate were available, the endpoint’s response categories and the clinical importance of changes would need to be understood alongside it.

How should planning illustrations be understood?

As a general statistical explanation, sample-size planning asks how many participants would be needed under stated assumptions to detect a chosen effect with a chosen probability, while controlling a chosen significance level. The registry’s planning description specifies a two-sided significance level of 0.05, equal allocation between the two arms, and a normal approximation. It says the effect to detect is a stated fraction of the observed effect. These are planning assumptions, not evidence that the trial had a particular probability of detecting an effect.

The record does not report the trial’s own sample-size justification. Nor does it report an observed primary-outcome effect from which a reader could judge the planning illustrations. Sample-size calculations based on an observed effect are particularly dependent on how that effect was estimated: a highly uncertain estimate from a small study may be an unstable basis for planning. Such illustrations are not observed power, and they do not repair the absence of a reported endpoint analysis.

Why does outcome distribution matter?

As a general explanation, statistical methods should match the data type and distribution. Counts of participants with an event are different from continuous measurements such as a symptom score. With sparse binary data, some standard approximations may perform poorly, especially when expected counts are small. Over-dispersion is a concern for count data when the variability is greater than a model expects; accounting for it can affect standard errors and interval estimates. The registry record does not report the distribution of the ultrasound outcome, a model, or a diagnostic assessment, so it is not possible to say which method would be appropriate for the recorded endpoint.

These concepts describe how clinical trial results are often analyzed; they do not identify methods used in this study. The registry record does not report a test, regression model, adjustment for baseline findings, confidence-interval method, interim analysis, or analysis population. The posted record therefore supports a description of the planned imaging question and selected planning assumptions, but not a reconstruction of the study’s statistical analysis.

10. Multiplicity, Missing Data and Analysis Populations

The record lists four outcome measures, with Shoulder Pain and Disability Index appearing three times among the secondary outcomes. It identifies Diagnostic Ultrasound as the primary outcome. The reason for the repeated secondary-outcome entries, the specific timing or scoring attached to each entry, and the relationship between the listed measures are not reported in the registry record.

When a study evaluates multiple outcomes, time points, or comparisons, there can be more opportunities for a result to appear unusual by chance. As a general statistical explanation, multiplicity procedures may control the overall chance of false-positive findings, or investigators may distinguish a primary outcome from secondary and exploratory analyses. The record does not report a multiplicity strategy, a hierarchy among the secondary outcomes, or which analyses were prespecified. With zero analyses listed, there are no reported inferential findings to assess for multiplicity.

Missing data are relevant to the primary imaging endpoint. The outcome description states that two participants in the PRP group were lost to follow-up and did not have completed six-month ultrasound imaging. The reason for loss to follow-up, the timing of withdrawal, and the observed baseline characteristics of those participants are not reported in the registry record. The record does not describe imputation, a complete-case analysis, sensitivity analyses, or another missing-data method. Missingness in other outcomes is not reported.

The analysis population is also not reported. It is therefore unclear whether the planned analysis was intended to include all randomized participants, only participants with complete follow-up, or another defined group. These omissions matter because the treatment comparison can depend on who is included and how missing outcomes are addressed. No analysis population or missing-data approach should be inferred from the enrollment count alone.

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 lists safety results for PRP injection into a partial-thickness rotator-cuff tear and subacromial steroid bursal injection. In the PRP group, 9 participants are listed at risk; serious adverse events, other adverse events, and deaths are each recorded as 0. In the steroid group, 2 participants are listed at risk; serious adverse events, other adverse events, and deaths are also each recorded as 0. No serious adverse-event terms are listed.

These figures mean that no events are recorded in the listed categories for the participants included in those safety denominators. They should not be interpreted as proof that an event cannot occur, or as a precise estimate of safety in a larger population. As a general statistical point, zero observed events in a small group leaves substantial uncertainty about the underlying event rate. The groups also have different listed denominators, so the raw counts alone do not support a direct safety comparison.

The registry record does not describe the adverse-event collection period, definitions, severity criteria, or completeness of follow-up for safety. The two PRP participants noted as lacking six-month ultrasound follow-up may or may not have had complete safety follow-up; that is not reported. Safety counts are therefore descriptive and should be kept separate from the unreported primary ultrasound analysis.

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

The record establishes that a randomized study was registered to examine PRP injection and subacromial steroid injection in relation to a six-month diagnostic-ultrasound endpoint. It also describes baseline ultrasound confirmation of a supraspinatus tendon tear, reports enrollment of 11, and records that the study was terminated. Those details clarify the study’s intent and status.

The record does not establish whether either injection changed tendon structure, whether one approach differed from the other, or whether any difference was clinically important. The primary outcome results and analysis are not reported in the registry record. An absence of reported results cannot be read as a finding of no effect, and it cannot establish that the approaches are equivalent. No estimate or confidence interval is available to show the likely size or precision of a comparison.

The project summary states that the goal was to identify a conservative approach for partial-thickness tears that might otherwise end with surgical correction. That goal is not itself an outcome. The listed primary endpoint is ultrasound, and the registry does not report results for surgery avoidance or a clinical decision about surgery. Shoulder Pain and Disability Index is listed as a secondary outcome, but its results are also not reported.

The safety record reports no serious or other adverse events and no deaths in the listed groups. These observations are limited to the recorded participants and safety categories. They are not a guarantee of safety, especially given the small enrollment and the absence of details about event ascertainment and follow-up.

In practical statistical terms, the posted registry information is descriptive rather than an evaluable efficacy report. It documents a research question and some study characteristics, but lacks the outcome counts, group comparison, and uncertainty estimates needed to judge the evidence for structural change.

13. Why This Trial Matters Statistically

This study illustrates why a trial’s registration details and its numerical results serve different purposes. The record identifies a randomized study and a six-month imaging question, but without group-level outcome data and an analysis, readers cannot estimate the treatment contrast. A clear clinical question does not by itself answer that question.

It also highlights the importance of a well-defined endpoint. “Diagnostic Ultrasound” names an assessment method, and the description explains that ultrasound was used to confirm a tear and later review structural change. But the record does not define the exact response categories or the threshold for a change. Without those rules, even a reported participant count could be difficult to interpret or reproduce.

The record also brings missing follow-up into view: two PRP-group participants did not have completed six-month ultrasound imaging after being lost to follow-up. Missingness is not merely a bookkeeping issue. As a general statistical principle, results can be sensitive to which participants lack measurements and how their outcomes are handled. The record does not report enough information to evaluate that issue.

Finally, the study is a reminder that safety counts, sample-size planning, and efficacy conclusions answer different questions. The recorded adverse-event counts describe events among the listed safety groups; they do not establish the imaging effect. Planning assumptions describe hypothetical detection scenarios; they are not observed power or trial results. Separating those concepts helps prevent a sparse registry record from being interpreted more strongly than its information permits.

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 for interpreting efficacy is the absence of a reported primary-outcome analysis. The registry lists zero analyses and does not report ultrasound response counts, a treatment contrast, a confidence interval, or a statistical test. The reason for study termination is not reported in the registry record, so its implications for completion and reporting cannot be determined.

Enrollment was 11, and two PRP-group participants are specifically noted as lost to follow-up without completed six-month ultrasound imaging. The record does not explain why follow-up was missed or how those observations were handled. It also does not report complete follow-up status for every participant and outcome. The small enrollment limits how much precision could be expected, but no effect or precision estimate is available to quantify that limitation.

The primary endpoint description leaves key measurement details unresolved. It identifies diagnostic ultrasound and structural change from baseline, but does not define response categories, image-reading procedures, or whether assessors were masked to treatment. The record says masking was single but does not identify who was masked. Randomization is listed, but the sequence-generation and allocation-concealment procedures are not described.

There is also a design-label ambiguity: the registry records randomized allocation and two interventions while labeling the model single group. The relationship among those entries is not explained. The record does not provide baseline group characteristics, a sample-size justification, an analysis population, or an analysis plan. These limitations prevent a detailed assessment of comparability, endpoint validity, and the intended handling of the data.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Non-Surgical Treatment for Rotator-Cuff Tears Using Platelet-Rich-Plasma — NCT02246530.
• Registry record last updated 2022-05-16; status last verified 2022-05.
• Results first posted 2022-05-16.
• 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

NCT02246530 is a terminated randomized study sponsored by the University of Alabama at Birmingham, with enrollment listed as 11. It examines PRP injection into a partial-thickness rotator-cuff tear and subacromial steroid bursal injection. The registry labels masking as single and the model as single group, while listing both intervention approaches.

The primary outcome is Diagnostic Ultrasound at 6 months post procedure, described as assessing structural changes relative to baseline. The record notes that two PRP-group participants were lost to follow-up without completed six-month ultrasound imaging. Shoulder Pain and Disability Index is listed among the secondary outcomes. No outcome analyses or efficacy results are reported in the registry record.

Safety entries record zero serious adverse events, zero other adverse events, and zero deaths in the listed groups. The record does not explain the termination or report a statistical analysis plan, sample-size justification, missing-data method, or analysis population.