The Relationship Between Lower Extremity Strength Ratios And Patient Reported Function After Anterior Cruciate Ligament Reconstruction

Abstract

PURPOSE: Strength deficits in hip abductors and adductors, knee extension and flexion post-ACLR have been observed as potential risk factors for ACL reinjury. To holistically quantify these deficits, strength ratios can be utilized. Patient reported outcomes (PROs) help determine subjective function and can influence clinical perception of patients’ readiness to return to play. The purpose of this study was to examine the relationship between hip and thigh strength ratios to PROs post-ACLR. METHODS: In total, 146 patients with primary unilateral ACLR (76 M/70 F, 24.0 ± 10.6 yr, 172.7 ± 10.5 cm, 79.1 ± 19.1 kg, 6.6 ± 3.1 mo post-ACLR) performed maximal bilateral isometric contractions of hip abduction (AB) and adduction (AD) to assess strength via peak torque in a supine hook lying position with hips and knees flexed to 45° and 90° respectively. Peak torque during knee extension (Q) and flexion (H) was assess seated with hips and knees flexed to 90°. Peak torque ratios of AB:Q, AB:H, AD:Q, AD:H, and H:Q were calculated. PROs scores of IKDC, KOOS, and ACL-RSI were recorded. Pearson r correlation coefficients were used to assess the associations among strength ratios and PROs with α set to 0.05. RESULTS: Weak negative relationships were seen between hip:thigh strength ratios and PROs of the ACLR limb (Table 1). Correlations between AB:Q and all PROs were statistically significant with r-values between -0.2 and -0.24, except for KOOS_ADL. AB:H was only significantly correlated with KOOS_ADL (r = -0.23). No significant findings were seen between H:Q ratios and PROs of the ACLR limb, nor were any significant findings seen between any contralateral limb strength ratios and PROs. CONCLUSIONS: Patients post-ACLR displayed weak negative relationships among hip:thigh strength ratios of the ACLR limb and PROs. The lack of a relationship amid H:Q and PROs, and presence of relationships between hip:thigh and PROs highlight the influence of hip strength deficits on patient function post-ACLR.