Muscle Weakness and Post-traumatic Knee OA: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Muscle Weakness and Post-traumatic Knee OA (NCT01879852), a randomized na study. The primary outcome is Change in International Knee Documentation Committee (IKDC) Subjective Knee Form Score.

2. Clinical Question

The clinical question concerns whether adding an intensive quadriceps program to standard rehabilitation is associated with a different average change in knee function over the study period. The primary outcome was the change in the International Knee Documentation Committee (IKDC) Subjective Knee Form Score between baseline, before surgery, and 7 weeks after surgery, following the intervention. The outcome is reported as a mean and standard deviation for each group, together with a mean difference comparing the intensive-strengthening group with standard rehabilitation.

The study also recorded a single-leg forward hop index and change in urinary concentrations of CTX-II, a collagen-related biomarker. Those outcomes offer other perspectives on function and cartilage-related biological change, but they are secondary to the stated primary question. The registry record does not report a formal hypothesis specifying the expected direction or minimum important difference. The results therefore describe the observed group averages and their statistical uncertainty; they do not by themselves establish a clinical threshold or explain why any difference occurred.

3. Trial Design

The registry record describes a randomized, parallel-group, single-blind study conducted at a single center. The evaluator was masked, while the record does not specify whether participants or rehabilitation providers were masked. The study status is completed. Enrollment is listed as 29, and the recorded study start and primary completion are 2008-10 and 2013-08.

Participants had a traumatic meniscal tear and underwent meniscectomy. Both groups received a 6-week rehabilitation period involving 12 visits. The comparison was standard rehabilitation versus standard rehabilitation with intensive quadriceps strengthening. The latter added high-intensity neuromuscular electrical stimulation and eccentric quadriceps exercises to the standard protocol. The registry record does not report further details about how randomization was generated, how treatment assignments were concealed, or how adherence to each exercise component was assessed.

The primary outcome was change in IKDC Subjective Knee Form Score from baseline before surgery to 7 weeks after surgery, following the intervention. The primary outcome description notes that 2 subjects in the standard rehabilitation group did not complete the intervention or post-treatment testing. The posted outcome summaries include 12.0 participants for standard rehabilitation and 13.0 for the intensive-strengthening group; those outcome denominators should be read as specific to the reported measure, not as a complete account of participant flow. The registry record does not report a participant-flow diagram or the reasons for missing outcome data.

Two secondary outcomes are posted: the Single Leg Forward Hop Index at 7 weeks after surgery and change in urinary CTX-II from baseline to 7 weeks after surgery. The record lists 4 outcome measures but posts 2 secondary outcomes. An analysis plan, allocation ratio, eligibility details beyond the meniscal tear and meniscectomy description, and the trial's original sample-size justification 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: 29 subjects were consented to the study. During pre-surgery (baseline) testing, 2 subjects were found not to have a meniscal tear (inclusion criterion) and were withdrawn from the study. Total number of subjects meeting eligibility criteria was 27.

Overall Study

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: 2 subjects in the Standard Rehabilitation group did not complete the intervention or post-treatment testing.

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.

Population: The target number of participants was determined statistically from preliminary data on primary outcome measures. The final population was based on feasibility.

6. Primary Endpoint

The registry lists the primary outcome as Change in International Knee Documentation Committee (IKDC) Subjective Knee Form Score, measured over Baseline (pre-surgery) to 7 weeks post-surgery (post-intervention).

The primary endpoint is change in the International Knee Documentation Committee (IKDC) Subjective Knee Form Score from baseline before surgery to 7 weeks after surgery, following the rehabilitation intervention. The IKDC is a self-reported measure of knee function that includes questions about symptoms and functional activity. Participants' responses are used to produce a summary score. The stated scale runs from 0 points, the lowest and worst possible score, to 100 points, the highest and best possible score.

Change scores are used to describe how the measure shifted over the specified period, rather than simply comparing the score at a single follow-up time. The registry reports each group's mean change and standard deviation, then reports the mean difference between the intensive-strengthening group and standard rehabilitation. A positive or negative change must be interpreted in relation to the scale direction and the definition of change; a between-group estimate then indicates which group had the numerically higher average change.

Self-reported function can capture how participants experience symptoms and activity, which may not be represented by a biological measurement alone. However, the registry record does not report a threshold for a clinically important difference, nor does it explain how missing responses were handled when computing the summary score. The endpoint therefore supports a comparison of recorded average changes, with those interpretive limits in mind.

7. Results Posted in the Registry

• Standard Rehabilitation + Quadriceps Intensive Strengthening: mean 20.60 versus 22.20 on control; difference -1.60 (95% CI -18.36 to 15.16), standardized effect d = -0.07; z-test p = 0.852.

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.

Single Leg Forward Hop Index

• 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:
  • Standard Rehabilitation + Quadriceps Intensive Strengthening: mean 90.10 versus 87.10 on control; difference 3.00 (95% CI -8.26 to 14.26), standardized effect d = 0.23; z-test p = 0.602.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between Standard Rehabilitation + Quadriceps Intensive Strengthening and the control. The interval gives the range of effects that remain compatible with the data.

Change in Urinary Concentrations of C-terminal Crosslinking Telopeptide of Type II Collagen (CTX-II)

• 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:
  • Standard Rehabilitation + Quadriceps Intensive Strengthening: mean -0.11 versus 0.01 on control; difference -0.12 (95% CI -0.24 to 0.00), standardized effect d = -0.77; z-test p = 0.058.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between Standard Rehabilitation + Quadriceps Intensive Strengthening and the control. The interval gives the range of effects that remain compatible with the data.

The secondary outcomes add perspectives beyond the primary self-reported knee-function measure: the Single Leg Forward Hop Index reflects a functional task, while urinary CTX-II is a biomarker measure. Their observed directions are mixed across outcomes rather than uniformly aligning with the primary point estimate. This is not inherently contradictory, because the measures assess different aspects of function and biology and use different scales.

These outcomes do not replace the primary comparison. The primary endpoint was identified as the main question, whereas secondary measures can provide supporting context or motivate hypotheses for additional research. A pattern across different measures may be informative descriptively, but it does not establish a common underlying effect, particularly when the registry record does not report a prespecified framework for interpreting relationships among the endpoints.

The registry record lists two secondary outcomes and reports no analyses for them. The posted group summaries and unadjusted comparisons can therefore be read as descriptive evidence, with uncertainty reflected in their intervals. They should not be promoted to confirmatory conclusions on their own. General statistical principle: testing multiple outcomes without an adjustment or clear hierarchy increases the risk that an apparently notable finding arises by chance. The registry record does not report a multiplicity adjustment or a plan defining how secondary outcomes would support the primary conclusion.

Accordingly, the secondary outcomes provide context but do not resolve the uncertainty in the primary estimate. Their directions, precision, and distinct measurement domains should be considered together, without treating any single secondary signal as definitive. Interpretation is further limited by the fact that the record does not explain whether missing measurements differed by outcome or how any missing secondary data were handled.

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

• Single Leg Forward Hop Index
• Change in Urinary Concentrations of C-terminal Crosslinking Telopeptide of Type II Collagen (CTX-II)

9. Statistical Interpretation

10. Statistical Methods Explained

The primary outcome is continuous: it is a score expressed in units on a scale. The registry reports the mean change in each group and the standard deviation. A mean describes the average observed change, while the standard deviation describes how dispersed individual observations are around that average. A larger standard deviation indicates greater spread in the observations; it is not the uncertainty of the group mean itself.

What does the mean difference represent?

The between-group mean difference is calculated in the direction intensive quadriceps strengthening minus standard rehabilitation. For the primary endpoint, the estimate is -1.6 units. A negative value means the intensive-strengthening group had the lower average change in the posted comparison. The estimate is a contrast between group averages, not a description of how every participant changed. Individual outcomes can vary substantially around a group mean, as the reported standard deviations indicate.

The comparison is unadjusted in the posted results. The registry record does not report the specific statistical test or any covariates used in an adjusted model. It also does not report whether the analysis followed an intention-to-treat population, a per-protocol population, or another analysis population. The p-value and interval should therefore be read as the posted unadjusted comparison, not as evidence about an unreported model.

How should a confidence interval be understood?

A confidence interval gives a range of values compatible with the observed data under the statistical procedure used. In general, a 95% confidence interval is produced by a method designed to cover the true parameter in 95% of repeated samples when its assumptions hold. It is not a statement that there is a 95% probability that this particular interval contains the true effect. Nor does it show the full range of individual participant outcomes. The primary interval, from -18.36 to 15.16 units, spans both negative and positive mean differences, reflecting substantial uncertainty about the direction and size of the between-group contrast.

The p-value is another summary of the data under a specified null hypothesis and statistical model. The primary unadjusted p-value is 0.852. It does not quantify the size of the effect or its clinical importance. A large p-value does not prove there is no difference, and it does not establish equivalence. Establishing equivalence would require a prespecified equivalence margin and an analysis designed for that purpose; neither is reported in the registry record.

Why does variability matter?

Standard deviations are large relative to the estimated mean difference in the primary outcome. General statistical principle: when individual observations vary widely and the sample is limited, estimates of average differences tend to be less precise. This helps explain why a near-zero point estimate can coexist with a broad interval. The interval describes uncertainty in the group contrast; it should not be mistaken for a prediction interval for an individual participant.

The secondary outcomes are also continuous measures, reported as group means and standard deviations. Their units differ: the hop index is expressed as a percentage, while the CTX-II change is expressed in log (ng/mmol). The magnitudes cannot be compared directly across these different scales. A mean difference of a given numerical size in one measure does not have the same meaning as the same numerical size in another.

What is the role of the unadjusted p-values?

The posted p-values are unadjusted. General statistical principle: when several outcomes are examined, the chance of seeing at least one apparently unusual result can increase if each is assessed separately without accounting for the number of comparisons. This does not mean a secondary result is necessarily false, but it does mean isolated unadjusted findings should be interpreted cautiously, especially when there is no reported hierarchy, adjustment strategy, or analysis plan. The registry record lists the primary endpoint, but does not report a multiplicity procedure.

Random allocation can, in principle, support a causal comparison by balancing factors across groups on average, but the validity of that interpretation also depends on implementation, follow-up, and analysis. The record identifies randomization and evaluator masking, yet does not report sequence generation, allocation concealment, participant masking, or a detailed missing-data approach. The stated primary outcome description identifies missing post-treatment data in the standard rehabilitation group. General statistical principle: if missingness is related to participant outcomes, analyzing only observed scores can distort the comparison. The registry record does not report enough to assess this possibility or the sensitivity of the result to missing data.

11. Confidence Intervals and Precision

The primary mean-difference estimate is -1.6 IKDC units, with a 95% confidence interval from -18.36 to 15.16. The interval extends on both sides of zero. This means the observed data do not pin down a single direction for the between-group difference: values favoring standard rehabilitation and values favoring intensive quadriceps strengthening are both compatible with the interval. The interval is also wide in relation to the point estimate, so the estimate is not precise.

Precision concerns how narrowly the data identify the group contrast, not whether the result is important or whether a treatment works. The interval is not a range containing 95% of participants' individual changes. It represents uncertainty around the estimated difference in average change. The group standard deviations, 21.6 and 21.1, show substantial variation in the primary scores, while the outcome summaries include 12.0 and 13.0 participants in the respective groups.

The unadjusted p-value of 0.852 is consistent with the interval crossing zero, but it should not replace consideration of the interval's full span. A nonsignificant comparison is not proof that the groups are identical. Conversely, the interval alone does not say which values would matter clinically because the registry record does not report a clinically important difference for the IKDC score. The practical meaning of the plausible values therefore cannot be resolved from this record.

For the secondary outcomes, their own intervals also convey uncertainty, and their scales differ from the primary endpoint. They should be interpreted on their respective units rather than ranked by numerical size. The registry record does not report adjusted estimates or a method for handling multiple comparisons. Overall, the posted summaries allow a reader to see the direction and uncertainty of the recorded group differences, but they do not provide a precise estimate of a definitive treatment effect.

12. Planning a Similar Trial: Sample Size

This is a planning illustration, not a re-evaluation of the original trial. It asks: if a new study wanted to detect a difference like the one observed, or a smaller one, how large would it need to be? It is deliberately not “observed power” of the finished trial, which is not a meaningful quantity.

The sample-size figures are planning illustrations based on the observed effects, not the trial's original design justification. Each entry gives the number of participants per arm for the continuous outcomes in this record; these figures are not total events. The registry record does not report the trial's original sample-size assumptions or justification.

The stated planning assumptions are a two-sided significance level of 0.05, equal allocation between the two arms, and a normal approximation. The effect to detect is set to the stated fraction of the observed effect. The entries for 80% power indicate the approximate participants per arm for a design that would have an 80% chance of detecting an effect of the specified size under those assumptions, if that effect were true. The entries for 90% power express the corresponding planning target for a higher chance of detection.

The rows describe planning for the full observed effect, 75% of the observed effect, and 50% of the observed effect. Smaller effects require more participants to detect under the same assumptions, which is why the planning figures increase as the assumed effect becomes smaller. These are illustrative sample-size estimates, not observed power. Observed power is not a useful substitute for interpreting the estimate and its confidence interval, and these planning figures do not show what the original trial was designed to detect.

The values depend on the observed effect used as their starting point. When that effect is estimated from a small study, it may be unstable, so the resulting planning figures can also be uncertain. They should not be read as a recommendation for a future study without a separate design process that defines the target effect, population, outcome, analysis, and other relevant assumptions.

13. How the Sample Size Is Derived

Power is the probability that a study of a given size rejects the null hypothesis when a specific true effect exists. It depends on four things: the effect to detect, the variability of the outcome, the significance level (here a two-sided α of 0.05, so z_1−α/2 = 1.960) and the desired power (z_1−β = 0.842 for 80% and 1.282 for 90%).

Formula

n is the number of participants in each arm, Δ is the difference in means to detect and σ is the common standard deviation.

Worked calculation for this trial

1. Observed difference Δ = -1.600; pooled standard deviation σ = 21.341.
2. n = 2 × (1.96 + 0.842)² × 21.341² / -1.600² = 2,792.6, rounded up to 2,793 participants per arm for 80% power.

The smaller-effect rows in the table above repeat the same calculation with the effect multiplied by 0.75 and 0.5 (for ratios, applied to the logarithm of the ratio).

R code

alpha <- 0.05
z_a   <- qnorm(1 - alpha / 2)          # two-sided
delta <- -1.6                      # observed difference in means
sigma <- 21.3405920621996                     # pooled standard deviation
n_per_arm <- function(power, frac = 1) {
  ceiling(round(2 * (z_a + qnorm(power))^2 * sigma^2 / (delta * frac)^2, 6))
}
for (f in c(1, 0.75, 0.5))
  cat(sprintf("%3.0f%% of observed effect: n per arm = %s (80%% power), %s (90%% power)\n", 100 * f,
              format(n_per_arm(0.80, f), big.mark = ","), format(n_per_arm(0.90, f), big.mark = ",")))

# Check against R's built-in function (t-based, so very slightly larger)
cat("power.t.test:", round(power.t.test(delta = delta, sd = sigma, power = 0.80)$n, 1), "\n")

# Simulation: exact two-sample t-test using simulated means and variances
set.seed(1879852)
n    <- n_per_arm(0.80)
reps <- 20000
m_diff <- rnorm(reps, delta, sigma * sqrt(2 / n))             # difference in sample means
s2     <- sigma^2 * rchisq(reps, 2 * (n - 1)) / (2 * (n - 1))   # pooled sample variance
tstat  <- m_diff / sqrt(s2 * 2 / n)
cat(sprintf("Simulated power at n = %s per arm: %.3f (%d replicates)\n", format(n, big.mark = ","), mean(abs(tstat) > qt(0.975, 2 * (n - 1))), reps))

Output from running the code

100% of observed effect: n per arm = 2,793 (80% power), 3,739 (90% power)
 75% of observed effect: n per arm = 4,965 (80% power), 6,647 (90% power)
 50% of observed effect: n per arm = 11,171 (80% power), 14,955 (90% power)
power.t.test: 2793.6 
Simulated power at n = 2,793 per arm: 0.800 (20000 replicates)

The simulation draws many sets of group means and variances at the planned sample size and counts how often the two-sample t-test rejects the null. It should land close to the target power; at very small required sample sizes it can fall below it, because the normal approximation is rough there.

14. Multiplicity, Missing Data and Analysis Populations

The registry identifies change in IKDC Subjective Knee Form Score as the primary outcome and lists secondary outcomes for the hop index and urinary CTX-II. The record does not report a statistical analysis plan that specifies testing order, a multiplicity adjustment, or how results across endpoints would be combined. The posted secondary comparisons are unadjusted. General statistical principle: examining several outcomes can raise the chance of at least one apparently notable result when each is considered separately. This is one reason secondary findings usually carry less confirmatory weight than a prespecified primary analysis.

Missing data are noted for the primary endpoint: 2 subjects in the standard rehabilitation group did not complete the intervention or post-treatment testing. The posted primary outcome summaries include 12.0 participants in standard rehabilitation and 13.0 in the intensive-strengthening group. The registry record does not report why the participants did not complete testing, whether missingness was related to their outcomes, or whether any method was used to account for missing values. It also does not report sensitivity analyses comparing alternative assumptions about missing data.

The record does not state whether the analysis included all randomized participants, only participants with observed outcomes, or another defined population. An intention-to-treat analysis, per-protocol analysis, and complete-case analysis answer different questions and depend on different assumptions; the analysis population used is not reported in the registry record. The available outcome denominators should therefore be read as the numbers contributing to those specific summaries, not as proof of a particular analysis population.

The registry record also does not report imputation methods, a plan for handling protocol deviations, or whether secondary-outcome missingness was assessed. These omissions limit assessment of robustness. They do not demonstrate that the analysis was inappropriate, but they leave important features of the analysis and uncertainty unaddressed in the public record.

15. 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 0% reporting threshold.

The registry reports serious adverse events for the standard rehabilitation group as 0 affected among 14 at risk, and for standard rehabilitation plus intensive quadriceps strengthening as 0 affected among 13 at risk. Other adverse events are also reported as 0 affected among 14 at risk in standard rehabilitation and 0 affected among 13 at risk in the intensive-strengthening group.

These figures describe the adverse-event counts recorded in the registry. They do not establish that no adverse events of any kind occurred outside the categories or reporting period represented by these figures, and they do not compare risks with high precision. The registry record does not report deaths in these groups, so death counts are not reported in the registry record. No serious adverse-event terms are listed.

Safety counts should be interpreted in light of the study's size and follow-up. Zero recorded events in these summaries does not rule out uncommon events or events not captured in the registry report. The record does not provide further detail about event definitions, severity grading, relatedness, or the method used to collect adverse-event information.

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

The posted primary result describes a small difference in average IKDC change between the rehabilitation groups, with an estimate of -1.6 units and a confidence interval that includes differences in either direction. This indicates uncertainty about the size and direction of the between-group contrast. It does not establish that the approaches are equivalent, and it does not establish that one approach caused a meaningful improvement relative to the other.

Both group averages were positive on the IKDC scale, for which higher scores are described as better. That finding describes the changes recorded within each group over the period; it does not isolate the contribution of rehabilitation from surgery, natural recovery, or other factors. The randomized comparison is the relevant contrast for the intervention question, but the precision of that contrast is limited. The registry record does not report a threshold for clinically important change, so statistical uncertainty cannot be translated into a judgment about clinical importance from these data alone.

The secondary outcomes offer additional measurements, but their observed directions are not uniform and their analyses are unadjusted. They should be viewed as context rather than as definitive confirmation of the primary result. The absence of a reported multiplicity strategy, analysis population, and missing-data approach further limits how strongly the secondary findings can be interpreted.

The results apply to the study population and rehabilitation programs described in the record. The record does not provide enough detail to determine how well the findings would generalize to other settings or populations. Nor does it support a conclusion about long-term outcomes, because the posted primary and secondary measurements are at 7 weeks after surgery. Overall, the statistics describe short-term observed group averages and their uncertainty; they do not establish a broader treatment claim.

17. Why This Trial Matters Statistically

This trial is statistically instructive because it separates an observed group difference from the certainty of that estimate. The primary point estimate is close to zero, but its confidence interval is wide and includes values on both sides of zero. Looking only at the estimate or the p-value would miss the range of effects compatible with the data. The interval makes the limited precision visible.

The study also illustrates why the mean difference should be interpreted alongside the spread of individual measurements and the number contributing to each outcome summary. The primary score varies substantially across participants compared with the estimated group contrast. In general, high variability and limited outcome samples constrain precision, even in a randomized study. Randomization supports a fair comparison in principle; it does not ensure that a small trial will estimate the effect precisely.

A further lesson is the importance of distinguishing primary from secondary outcomes. Functional performance and a urinary biomarker can complement a self-reported measure, but they address different constructs. A mixed pattern across endpoints should prompt careful interpretation, not selective emphasis on whichever result appears most favorable. Without a reported multiplicity plan and analysis strategy, secondary findings are best treated as exploratory or descriptive.

Finally, missing outcome information and unreported analysis details matter to interpretation. The record notes noncompletion in the standard rehabilitation group but does not describe how missing data were addressed or define the analysis population. Clear reporting of these features, along with a clinically meaningful threshold and the original sample-size rationale, would help readers judge what the estimates can support. The record's transparency about outcomes and group summaries is useful, while the unreported details leave important statistical questions open.

18. 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 primary outcome summary is based on 12.0 participants in standard rehabilitation and 13.0 in the intensive-strengthening group, and the record notes that 2 subjects in standard rehabilitation did not complete the intervention or post-treatment testing. The reasons for noncompletion and the handling of missing outcome data are not reported in the registry record. This makes it difficult to assess whether the observed participants represent the randomized groups without bias.

The primary confidence interval is broad, limiting precision. The registry record does not report a clinically important difference for the IKDC scale, so the practical importance of the plausible between-group values cannot be judged from the record. The original sample-size justification is also not reported in the registry record; the separate planning illustrations are not a substitute for it.

Important design and analysis details are absent. The record does not report the randomization sequence method, allocation concealment, participant masking, the analysis population, the statistical test, or an adjustment strategy for multiple outcomes. It does identify evaluator masking, but does not describe how masking was maintained or assessed. These omissions do not establish that the methods were deficient; they limit independent assessment of bias and analytical choices.

The secondary outcomes are reported without analyses identified in the registry record, and their unadjusted comparisons should be treated cautiously. The posted follow-up is short-term, at 7 weeks after surgery, so the record does not establish whether group patterns persist later. The single-center setting and the limited description of the eligible population also constrain judgments about generalizability. Finally, the adverse-event record provides counts but not definitions, collection methods, relatedness, or detailed follow-up, limiting interpretation of safety reporting.

19. Related Tutorials

20. Related Statistical Calculators

21. Sources

• ClinicalTrials.gov: Muscle Weakness and Post-traumatic Knee OA — NCT01879852.
• Registry record last updated 2014-10-01; status last verified 2014-09.
• Results first posted 2014-09-11.
• Data retrieved from ClinicalTrials.gov on 2026-11-09.
• Group sizes, means, event counts and sponsor-reported p-values are reproduced as posted. Effect estimates, confidence intervals and p-values not attributed to the sponsor are independently calculated from the posted summary statistics.

22. Record Summary

NCT01879852, titled “Muscle Weakness and Post-traumatic Knee OA,” is a completed, randomized, parallel-group, single-blind evaluator study sponsored by the University of Florida. It enrolled people with a traumatic meniscal tear who underwent meniscectomy and compared standard rehabilitation with standard rehabilitation plus intensive quadriceps strengthening over 6 weeks and 12 visits.

The primary outcome was change in IKDC Subjective Knee Form Score from baseline before surgery to 7 weeks after surgery. The estimated mean difference for intensive strengthening versus standard rehabilitation was -1.6 units, with a 95% confidence interval from -18.36 to 15.16 and an unadjusted p-value of 0.852. The interval indicates substantial uncertainty about the between-group difference.

The record also posts a hop index and urinary CTX-II as secondary outcomes. It reports no serious or other adverse events in the listed group summaries. Details about the original sample-size rationale, analysis population, missing-data methods, and multiplicity strategy are not reported in the registry record.