Test-retest reliability of clinical measurements of lower extremity joint motion and alignment in the pediatric population

Abstract

Purpose: Manual anthropometric evaluations of pediatric lower extremities are essential in orthopedic pediatric practice due to their noninvasive and time-feasible nature. Therefore, this study aims to assess the test-retest reliability of clinical measurements obtained on children to examine measurement stability over time.

Methods: In a test-retest design, data were collected from 50 Danish school children with 5-to 6 weeks between sessions. Measurements encompassed the joint range of motion (ROM), rotational profile, and angular alignment of lower extremities for a representative sample of school children. Reliability was assessed using intraclass correlations (ICC), and agreement was assessed using limits of agreement (LoA) and precision.

Results: Reliability analysis revealed excellent results for foot length (ICC > 0.9), good results for foot width (ICC < 0.9), and poor to moderate results for all other measurements (ICC < 0.5, ICC < 0.75). Agreement results for hallux valgus were acceptable (within established reference) and the remaining variables were not acceptable (outside established reference).

Conclusions: The majority of the manual assessment procedures were found to have poor reliability. This study highlights the need for reliable and time-efficient tools to assist clinicians in assessing manual clinical measurements and future research should explore this.

Level of evidence: Level III.

Keywords: pediatric lower extremity; reliability; reproducibility; stability; test–retest.

Figure 1.

Line of equivalence plots and mean difference plots for foot length, knee flexion, and knee extension. Foot length exhibits excellent reliability, knee flexion exhibits moderate reliability, and knee extension exhibits poor reliability. Line of equivalence plots. Horizontal axis; value at the test session, vertical axis; value at retest session, the red line; the line of equivalence. Mean difference plots. Horizontal axis; the average between test and retest, vertical axis; the difference between test and retest, the red line; marks zero, the dark-blue line; the mean difference, the light-blue line; limits of agreement.