The Relationship Between Childhood Opportunity Index On Strength Outcomes 4-6 Months After ACL Reconstruction

The Childhood Opportunity Index (COI) is a social determinants of health measure involving education, environment, and socioeconomic factors. Although lower COI is associated with poor health outcomes in all age groups, its effect on anterior cruciate ligament reconstruction (ACLR) outcomes is unknown. Mid-stage ACLR recovery (4-6 months) is crucial as patients begin to return to sport. Understanding COI’s impact on knee strength may provide insight on how community opportunity impacts recovery after ACLR. PURPOSE: To determine the association between COI and knee extension and flexion strength 4-6 months post-primary, unilateral ACLR. We hypothesize individuals with higher COI (i.e., greater opportunity) will demonstrate more symmetrical strength compared to those with lower COI. METHODS: Participants from the ARROW clinical outcomes registry were included in this cross-sectional analysis. For COI 3.0, zip codes were used to categorize participants as very low, low, moderate, high, and very high opportunity. Strength was assessed during 5 repetitions of isokinetic knee extension and flexion at 60°/s and limb symmetry indices (LSI, %) were calculated. Linear regression with very high COI was used as the reference group to determine if COI is associated with LSIs. RESULTS: A total of 597 were included in this analysis (Table 1). Age, time since surgery, and graft source were significantly different between COI groups. When compared to individuals with very high COI, individuals with moderate, low, and very low COI demonstrated 9.9% (p < 0.001), 13.2% (p < 0.001), and 14.0% (p < 0.001) lower knee extension LSI, respectively (R2 = 0.19). Knee flexion LSI was not different between COI groups (R2 = 0.02). CONCLUSION: Individuals with the greatest opportunity had better quadriceps strength symmetry compared to those with lesser opportunity following ACLR. Clinicians and researchers should be aware of the influence of community opportunity on mid-stage ACLR recovery. Table 1. - Characteristics and strength outcomes in participants by COI 3.0 rank. Very High (n = 175) High(n = 118) Moderate(n = 121) Low(n = 75) Very Low(n = 108) p Age (years) 18.14.5 18.64.7 18.75.7 16.83.3 16.21.9 <0.001* Biologic Sex (% Female) 54.9% 50.0% 42.1% 37.3% 42.6% 0.05 Months since surgery 5.80.77 5.70.77 5.70.81 5.90.56 6.00.53 0.02* Graft Source (n (%)) <0.001* BTB 61 (34.9%) 53 (44.9%) 59 (48.8%) 41 (54.7%) 56 (51.9%) HS 68 (38.9%) 38 (32.2%) 31 (25.6%) 15 (20.0%) 27 (25.0%) QT 43 (24.6%) 23 (19.5%) 27 (22.3%) 11 (14.7%) 13 (12.0%) Other 3 (1.7%) 4 (3.4%) 4 (3.3%) 8 (10.7%) 12 (11.1%) Knee Extension LSI (%) 80.629.1 74.719.6 68.923.5 70.122.7 70.319.7 Knee Flexion LSI (%) 94.716.3 94.619.6 94.217.8 95.716.9 97.723.5 BTB, bone-patellar tendon-bone autograft; HS, hamstring autograft, QT, quadriceps tendon autograft; LSI, limb symmetry index = ((ACLR limb/Uninvolved limb)x100%); * indicates p < 0.05