Level 4.

Level IV, retrospective case series.

No abstract

IV (prognostic case series).

Objectives: To aid in the interpretation of Pedi-IKDC scores by characterizing normative data in children and adolescents. Also, to validate the Pedi-IKDC by examining differences in Pedi-IKDC scores between patients with knee ailments compared to patients without a history of knee problems. Methods: Cross-sectional survey of 2000 children and adolescents aged 10-18 years living in the United States, recruited by ORC International to obtain equal numbers by sex and by integer age group. In addition to completing the Pedi-IKDC for one study-designated "index" knee (right or left), subjects were asked demographic questions and for information on history of knee surgery and recent (four weeks) activity limitations. Raw Pedi-IKDC total scores were re-scaled to a 0-100 scale. Non-parametric Wilcoxon or Kruskal-Wallis tests were used to compare subgroup scores and the van Elteren test was used to adjust for age. Unadjusted and adjusted p-values were similar and only unadjusted values are reported. Results: Numbers of respondents are uniform with respect to age and sex, with 11% in each age group (10-18) and 50% female. 68% identified themselves as white, and 86% as non-Hispanic. 49 states and DC are represented. 136 (7%) reported prior surgery in one or both knees; 79(4%) in the index knee. The Pedi-IKDC score distribution is skewed left with mean score (±SD) of 86.7(±16.8), median 94.6 and 34% reaching the ceiling value of 100. Subjects reporting prior surgery or limited activity in the index knee had median Pedi-IKDC scores about 25 points lower than those without these histories (p<0.0001 for both comparisons). In contrast, although statistically significant, the variation by age (p=0.02), race (p=0.02), ethnicity (p=0.01), and level of sports/exercise participation (p=0.04) was much smaller (all ranges of median scores <4.5). There were no significant differences by sex or geographic region. Conclusion: There is only minor variation in Pedi-IKDC scores across demographic factors. The strong association between Pedi-IKDC score and prior knee surgery and also with recent limitation of activity in the index knee supports the construct validity of the Pedi-IKDC. Using a large, broadly representative sample, this study supports the use of the Pedi-IKDC as a knee specific outcome instrument for pediatric patients aged 10-18 and provides normative values to aid the interpretation of scores in this age range.