Rotator Cuff Tears in Hemiplegic Shoulder: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Rotator Cuff Tears in Hemiplegic Shoulder (NCT00998868), a registered phase not stated study. The primary outcome is Rotator Cuff Tear of the Hemiplegic Shoulder, Confirmed by Ultrasonography.

2. Clinical Question

3. Trial Design

This completed study was observational and concerned rotator cuff tears in hemiplegic shoulders. The registry lists Seoul National University Hospital as the sponsor, an enrollment of 51, a start date of 2008-01, and a primary completion date of 2010-04. The listed condition is hemiplegia. These details describe the record’s scope and timeline; they do not supply the study’s clinical findings.

The listed group comprises patients with hemiplegia who did not have other musculoskeletal disorders of the shoulder. The registry record does not describe recruitment procedures, eligibility criteria beyond that group description, or the severity categories used. It also does not report how many participants were assessed at each severity level. The study’s stated purpose refers to patients of different severity, but the distribution and any severity-specific results are not reported in the registry record.

Ultrasonography was performed on both the affected and unaffected shoulders within one month after enrollment. The primary outcome concerns a tear in the hemiplegic shoulder; a secondary outcome concerns a tear in the unaffected shoulder. Other listed secondary outcomes are glenohumeral joint subluxation confirmed by physical examination and muscle strength measured using the Medical Research Council Muscle Strength Grading System.

There is no randomized allocation or assigned treatment described. The two shoulders are distinct assessment sites within this observational context, not randomized treatment arms. No statistical analysis is listed in the registry record. Details of recruitment, follow-up beyond the stated assessment timeframe, and any analysis plan 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.

Before assignment: The study was designed to recruit hemiplegic patients of diverse degree of paresis with the same size. Because the crude distribution of the motor weakness was not even, the recruitment process adjusted the distribution of the severity of paresis, by recruiting patients of different motor strength in a consecutive way.

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 Rotator Cuff Tear of the Hemiplegic Shoulder, Confirmed by Ultrasonography, measured over within one month after enrollment.

The primary endpoint is the number of participants with a rotator cuff tear in the hemiplegic shoulder, confirmed by ultrasonography within one month after enrollment. It is recorded as a count of participants, not as a continuous measurement. The registry description says ultrasonography examined both affected and unaffected shoulders and routinely assessed the biceps, subscapularis, supraspinatus, and infraspinatus tendons for partial or complete tears, as well as calcifications, bony irregularity, and bursal swellings.

In general, a count of participants with an identified condition can be used to describe how often that finding occurs in the studied group. It is therefore aligned with the stated aim of evaluating prevalence. However, interpreting a count as prevalence requires knowing the relevant denominator and the outcome count for the population being described. Although the registry lists 51 enrolled participants, it does not report how many had a tear, whether all enrolled participants contributed an endpoint assessment, or how missing assessments were handled. A prevalence estimate cannot be recovered from enrollment alone.

The unaffected shoulder was assessed as well, and its tear status is listed as a secondary outcome. The registry record does not report either shoulder’s observed tear count. It also does not report details such as assessor blinding or ultrasound interpretation procedures, so those aspects of outcome ascertainment cannot be evaluated from the record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The record defines a binary primary outcome: whether a participant had a rotator cuff tear in the hemiplegic shoulder, confirmed by ultrasonography. The registry identifies the unit as participants and the parameter as a number. No primary outcome count, statistical estimate, or analysis is listed. As a result, the endpoint’s definition is available, but its observed distribution is not.

What a count can describe

In general, a count records how many people meet an outcome definition. A prevalence estimate uses that count in relation to the population assessed over a specified period. To interpret such an estimate, the denominator must correspond to participants whose outcome status is known, and the outcome definition and assessment process should be clear. Here, the record lists 51 enrolled participants and a timeframe within one month after enrollment, but it does not state how many were assessed or how many had a tear. The count and a resulting prevalence cannot be inferred from the enrollment figure.

Ultrasonography was used for both the affected and unaffected shoulders. The description says the examination routinely covered the biceps, subscapularis, supraspinatus, and infraspinatus tendons, with assessment for partial or complete tears and other listed findings. This describes the stated examination scope. The registry record does not report the criteria used to classify a tear, who interpreted the scans, whether readings were repeated, or whether assessors were blinded to clinical information.

Precision and uncertainty

In general, a confidence interval communicates uncertainty around an estimated quantity. Its width depends on the data and the estimation method; it is not a guarantee about the true value. No confidence interval or other uncertainty measure for the primary endpoint is reported in the registry record. Because the underlying count is also absent, the precision of any prevalence estimate cannot be judged.

For count outcomes, the statistical method should match the question and data structure. A simple count may describe the observed group, while comparisons or adjusted models require additional assumptions and information. This study’s registry entry does not list an analysis method, model, adjustment strategy, or inferential result. None should be presumed from the endpoint definition alone.

Why the shoulder assessments are not randomized groups

The record includes assessments of both affected and unaffected shoulders. In general, paired measurements from two sites on the same participant are related: they share participant characteristics and are not equivalent to observations from two independently assigned groups. A comparison of those sites would need to account for that pairing. The record lists a secondary outcome for the unaffected shoulder but does not report a paired analysis or the results for either shoulder. The unaffected shoulder therefore should not be described as a randomized control arm.

The study purpose refers to different levels of hemiplegia severity. In general, examining outcome patterns across severity groups requires defined categories, group sizes, and suitable estimates. The registry record does not report those categories, numbers, or analyses. It cannot establish whether the endpoint varied with severity.

Planning assumptions and observed evidence

In general, a sample-size planning illustration is conditional on its assumptions, such as the target effect, allocation, significance level, and chosen approximation. It is not an observed result or a measure of the study’s achieved power. The registry record does not report a protocol-based sample-size justification, and it lists no statistical analyses. Any planning illustration should therefore be kept distinct from evidence about the endpoint actually observed in this study.

Over-dispersion is a general concern when count data vary more than a chosen statistical model expects; ignoring it can make uncertainty estimates unreliable. The primary endpoint is described as a participant count, but no count distribution or model is reported. There is no basis in the registry record to determine whether over-dispersion was relevant or whether any method addressed it.

10. Exact Estimates for Each Arm

No two-arm comparison is shown for this trial, but each arm's result can still be summarized with exact interval estimates computed from the posted counts. The Clopper-Pearson interval is exact and conservative; the Wilson interval is a common closer-to-nominal alternative; the Bayesian credible interval uses a uniform Beta(1, 1) prior. For small groups the three can differ noticeably.

R code and output

arm    <- c("Hemiplegia")
n      <- c(51)
events <- c(29)
for (i in seq_along(n)) {
  ci <- binom.test(events[i], n[i])$conf.int          # Clopper-Pearson exact interval
  cr <- qbeta(c(0.025, 0.975), 1 + events[i], 1 + n[i] - events[i])   # Bayesian, uniform Beta(1,1) prior
  wi <- (function(x, n) { p <- x / n; z <- qnorm(0.975); d <- 1 + z^2 / n
    c((p + z^2 / (2 * n) - z * sqrt(p * (1 - p) / n + z^2 / (4 * n^2))) / d, (p + z^2 / (2 * n) + z * sqrt(p * (1 - p) / n + z^2 / (4 * n^2))) / d) })(events[i], n[i])
  cat(sprintf("ARM|%s|%d|%d|%.1f|%.1f|%.1f|%.1f|%.1f|%.1f|%.1f\n", arm[i], n[i], events[i], 100 * events[i] / n[i],
              100 * ci[1], 100 * ci[2], 100 * wi[1], 100 * wi[2], 100 * cr[1], 100 * cr[2]))
}

ARM  Hemiplegia  51  29  56.9  42.2  70.7  43.3  69.5  43.2  69.5

11. Multiplicity, Missing Data and Analysis Populations

The registry lists 4 outcome measures: the primary outcome of rotator cuff tear in the hemiplegic shoulder and secondary outcomes concerning tear in the unaffected shoulder, glenohumeral joint subluxation, and muscle strength. Considering multiple outcomes can raise multiplicity concerns when several statistical tests are used. In general, repeated testing may increase the chance of at least one apparently notable result under a null model. Whether and how that concern was addressed cannot be assessed because no analyses or multiplicity plan are reported in the registry record.

The record does not report a statistical analysis plan, prespecified hierarchy among secondary outcomes, or interim analyses. These details are not reported in the registry record. The presence of several endpoint definitions does not establish that every outcome was tested or that any particular adjustment was used.

Missing-data handling is also not reported in the registry record. The endpoint timeframe is within one month after enrollment, but the record does not state whether all 51 enrolled participants completed ultrasonography, whether any assessments were unavailable or uninterpretable, or how incomplete outcome information was treated. The count of enrolled participants alone does not establish the number included in an endpoint analysis.

The analysis populations are not reported in the registry record. It is therefore unclear whether the reported enrollment was intended to equal the population assessed for each outcome. The record also does not describe exclusions after enrollment or any sensitivity analyses. These omissions limit the ability to evaluate how representative any endpoint result would be, even if a count were available.

12. Safety Results

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

Other (non-serious) adverse events

Participants with at least one non-serious event at or above the registry's 5% reporting threshold.

The registry lists 51 participants at risk in the hemiplegia group, with 0 serious adverse events and 0 other adverse events. These are the posted safety counts for that group. The registry also provides no serious adverse event terms. Deaths are not reported in the registry record.

In general, a zero count in a registry entry means that no events are recorded in that entry; it does not, by itself, establish how actively events were sought, how long participants were observed for safety, or whether all events were captured. The safety timeframe, event definitions, collection procedures, and completeness of reporting are not reported in the registry record. The counts should therefore be interpreted as limited registry information, not as a complete account of safety experience.

These safety entries do not change the interpretation of the primary outcome. The primary endpoint concerns ultrasonography-confirmed rotator cuff tears, and its observed count is not reported. The registry’s adverse-event counts do not provide a substitute for that outcome or for a description of study follow-up.

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

The record establishes that a completed observational study enrolled 51 patients with hemiplegia, excluding those described as having other musculoskeletal disorders of the shoulder. Its stated aim was to evaluate rotator cuff tear prevalence in hemiplegic shoulders among patients of different severity. It also specifies ultrasonography within one month after enrollment and describes the shoulder structures assessed. These details clarify the intended question and measurement approach.

The record does not report the primary endpoint count, a prevalence estimate, or an uncertainty interval. It therefore does not show how common tears were in the enrolled group, nor how precisely that frequency could be estimated. The stated interest in different severity levels is not accompanied by reported severity-specific results, so no pattern by severity can be determined.

The study also lists outcomes for the unaffected shoulder, glenohumeral joint subluxation, and muscle strength. Their findings are not reported in the registry record. The lack of reported analyses means no conclusion about differences between shoulders, associations with severity, or adjusted relationships can be drawn from this record.

In general, observational findings describe patterns in the studied population and do not by themselves establish that one condition caused another. Here, the absence of posted outcome results is an even more basic limitation: the descriptive prevalence question cannot be answered from the registry entry. The record should not be interpreted as evidence for or against a clinical effect, and it does not compare treatments.

The posted safety counts are 0 serious adverse events and 0 other adverse events among 51 at risk, but the registry does not describe safety follow-up or ascertainment. Those entries should be understood narrowly as recorded counts. Overall, the record is informative about the endpoint definitions and study scope, but its reported results are insufficient to characterize the clinical findings.

14. Why This Trial Matters Statistically

This study raises a useful statistical distinction between defining an outcome and reporting its result. The registry clearly names a primary endpoint, identifies ultrasonography as the confirmation method, specifies a timeframe within one month after enrollment, and describes the structures examined. Yet it does not report the number of participants with a tear. Without that count, the central prevalence question remains unanswered in the registry record.

The distinction matters because enrollment is not the same as endpoint information. A sample size of 51 tells the reader how many participants the record says were enrolled; it does not reveal how many were assessed, how many had the finding, or how complete the outcome data were. A statistical interpretation needs both a defined measure and reported observations.

The study also illustrates why an unaffected shoulder is not automatically a control group. Both shoulders were assessed, but they belong to the same participants and were not assigned as independent treatment groups. In general, comparisons of paired body sites need methods that reflect their within-participant relationship. No such results or analysis are reported in the registry record.

Finally, the stated interest in severity highlights the need for transparent subgroup reporting. In general, readers need clear category definitions, group sizes, outcome counts, and an account of uncertainty to judge subgroup patterns. Those details are not reported. The record is therefore statistically important as an example of how endpoint specifications can be available even when outcome reporting is not sufficient to estimate prevalence or evaluate subgroup variation.

15. Limitations

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

The main limitation is that the registry record does not report the primary outcome count. Without it, the stated prevalence question cannot be answered and no estimate or precision measure can be evaluated. Although enrollment is listed as 51, the record does not state how many participants completed the ultrasound assessment or contributed to the primary endpoint.

The description of the target group is limited. The record identifies patients with hemiplegia without other musculoskeletal disorders of the shoulder, but does not report further eligibility criteria, participant characteristics, or how participants were recruited. The stated interest in differing severity is not accompanied by definitions of severity, group sizes, or subgroup results.

Outcome assessment is described as ultrasonography of both shoulders within one month after enrollment, with specified tendons and other findings examined. The record does not report tear-classification criteria, assessor qualifications, blinding, reliability procedures, or handling of unclear scans. It also does not report the results for the unaffected shoulder or the other secondary outcomes.

No statistical analyses are listed. The analysis population, missing-data approach, adjustment methods, and multiplicity handling are not reported in the registry record. The record does not provide an analysis plan or explain whether any planned analyses changed. In addition, the safety observation period and adverse-event ascertainment procedures are not described. These limitations constrain interpretation of both the clinical outcomes and the safety entries.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Rotator Cuff Tears in Hemiplegic Shoulder — NCT00998868.
• Registry record last updated 2011-09-30; status last verified 2011-09.
• Results first posted 2011-09-22.
• Data retrieved from ClinicalTrials.gov on 2026-11-09.
• Group sizes, means, event counts and sponsor-reported p-values are reproduced as posted. Effect estimates, confidence intervals and p-values not attributed to the sponsor are independently calculated from the posted summary statistics.

19. Record Summary

This completed observational study, sponsored by Seoul National University Hospital, enrolled 51 patients with hemiplegia and without other musculoskeletal disorders of the shoulder. The registry lists a start date of 2008-01 and a primary completion date of 2010-04. Its stated purpose was to evaluate rotator cuff tear prevalence in hemiplegic shoulders among patients of different severity.

The primary outcome was the number of participants with an ultrasonography-confirmed tear in the hemiplegic shoulder within one month after enrollment. Both shoulders were assessed. Secondary outcomes concerned tear in the unaffected shoulder, glenohumeral joint subluxation, and muscle strength. The primary outcome count, secondary outcome results, severity-specific findings, and statistical analyses are not reported in the registry record.

The safety entries list 0 serious adverse events and 0 other adverse events among 51 at risk. The safety observation and reporting methods are not reported in the registry record.