Background

The HSS Pedi-FABS activity scale has become increasingly used in children ages 10-18 since its development in 2013. Research has demonstrated the utility of the measure in general youth athletes and for young patients with a knee injury, however limited information is available regarding use in evaluating upper extremity, other specialized athletes, or as an activity measure following treatment for other joints. The purpose of this study is to assess the validity, sensitivity, and distribution of the Pedi-FABS activity scale when compared across commonly injured parts of the body.

Methods

A retrospective review of youth athletes age 6-19 presenting for evaluation at a single pediatric sports medicine clinic between April 2016 and July 2020 was performed. Participants were included if they completed a pre-visit intake questionnaire and the HSS Pedi-FABS as part of standard of care treatment. Patient demographics, sport, level of competition, frequency of sport participation, and HSS Pedi-FABS scores were compared for each injury subgroup based on body location (ankle, knee, hip, elbow, or shoulder). A Kruskal-Wallis test used to compare average scores in each subgroup. HSS Pedi-FABS scores were analyzed for a floor or ceiling effect. As defined in the literature, a floor or ceiling effect was determined to be present if more than 15% of respondents scored the lowest or highest possible score.

Results

2459 sports medicine patients (mean age 14.4±2.5 years; 53.2% females) reported participating in sports for 9.5±7.9 hours per week during 33.1±19.7 weeks per year with 6.1±3.4 years of participation in their primary sport. Males (21.4±8.3) scored significantly higher than females (18.1±9.4) on the HSS Pedi-FABS (p<0.01). Mean scores for each subgroup were: ankle 19.9±8.9; knee 19.2±9.3; hip 15.2±10.5; elbow 22.5±6.9; and shoulder 20.9±8.9 (p<0.01). Broad distribution was seen in each body location with no floor or ceiling effects. Participants with elbow injuries had significantly higher scores than those with hip or knee injuries(p<0.01). Those with hip injuries had significantly lower scores than all other subgroups (p<0.01).
While HSS Pedi-FABS scores did not correlate with age (r=0.00, p=0.86), a correlation was observed with hours per week (r=0.32, p<0.01) and days per week (r=0.32, p<0.01) overall and in each group (ankle: r= 0.33, 0.44 / knee: r= 0.32, 0.31 / hip: r= 0.24, 0.25 / elbow: r= 0.37, 0.42 / shoulder: r= 0.36, 0.30; p<0.05 for all). An inverse correlation was observed between HSS Pedi-FABS and Days from Injury to Presentation (r=-0.30, p<0.01). Select/elite level athletes scored higher on average than those reporting only school/recreational competition (23.0 vs 20.6, p<0.01).

Conclusion

The correlations with hours of participation per week and days per week without floor or ceiling effects demonstrates the validity and sensitivity of the HSS Pedi-FABS for use in variable athlete types with injuries to five parts of the body. The lack of an association with age, differences between sex, injury groups and competition levels, and an association with days to presentation may demonstrate the utility of the HSS Pedi-FABS as an independent measure for comparing pediatric athletes across injuries and sports.