ESTIMATED PERFORMANCE FOR AGE: A NOVEL CRITERION FOR RETURN TO SPORT AFTER ANTERIOR CRUCIATE RECONSTRUCTION AND ITS PERFORMANCE COMPARED TO LIMB SYMMETRY INDICES

The use of physical performance tests (PPT) for assessing readiness for return to sport (RTS) after ACL reconstruction in children is typically assessed based on a limb symmetry index (LSI). However, recent data show that: 1) healthy pediatric athletes have significant limb asymmetries at baseline and 2) the non-operative limb deconditions after ACLR, so return of LSI is not synonymous with return to pre-injury performance. We previously established a cohort of 100 healthy pediatric athletes and created growth curves for performance on 7 common PPT, allowing for the calculation of a performance percentile (PP) for any given individual based on their age. The current study explores the use of PP in a cohort of pediatric patients 6 months out from ACLR. We hypothesized that return to expected performance for age (EPFA, defined as the 50th percentile of performance among healthy volunteers of a given age) would be a more stringent criterion than 90% LSI. We performed a retrospective analysis of a prospective cohort of consecutive patients (< 19 years) undergoing ACL reconstruction between 2016-2019. Patients were excluded if they did not have RTS testing 6 months after surgery (+/- 6 weeks). RTS testing consisted of 7 PPT (Figure 1). Patients were then categorized into passing and failing groups based on two cutoffs: 1) LSI > 90% and 2) PP > EPFA (50th percentile). The prevalence of passing based on these two criteria were compared using contingency analysis. A multivariable linear regression was performed to assess the effects of demographic variables on PP. Sixty-three patients were included (57% male, mean age 14.2 ± 2.4 years). Mean time from surgery to RTS testing was 181.5 ± 15.1 days. More patients were able to achieve 90% LSI than EPFA for all PPT except the timed hop (Figure 1). On average, 58% met LSI > 90% compared to only 41% meeting EPFA. Reaching 90% LSI correlated weakly with reaching EPFA for 4 of the 7 PPTs. However, of patients that would have passed based LSI, only 36.2-63.2% would have passed based on meeting EPFA (Figure 2). There was no consistent effect of age, sex, or graft type on PP. Six months after ACL reconstruction, fewer pediatric athletes can meet EPFA than can meet 90% LSI. Additionally, PP does not clearly correlate with LSI, suggesting that these criteria provide complementary information. Future studies investigating the use of EPFA as a cutoff for RTS are warranted. Figure 1:. Prevalence of 50th Performance Percentile and 90% Limb Symmetry Index (LSI) for each PPTFigure 2:. Prevalence of Above or Below the 50th Performance Percentile for Patient that reached a passing LSI (90%).

Duke Scholars

Author Emily Reinke