The Relationship Between Hip And Thigh Muscle Strength After Acl-reconstruction

Abstract

PURPOSE: Weakness post ACL reconstruction (ACLR) of hip and thigh muscles are evaluated to track rehabilitation progress and/or inform decisions about return to sports. Lower extremity muscle adaptations are common mechanisms by patients coping with muscle weakness. Relationships among hip and thigh strength measures after reconstruction in ACLR patients may help identify potential coping mechanisms and targets for therapeutic intervention. METHODS: Thirty-four patients with primary unilateral ACLR (21.09±6.70yr, 18M, 170.82±11.95cm, 76.82±21.36kg, 7.97±5.22 mo post ACLR) performed maximum isometric contractions for hip abduction (AB) and adduction (AD) in a supine hook-lying position with the hips flexed to 45-degrees and knee flexed to 90-degrees and knee extension (EX) and flexion (FL) while seated with the hip and knee flexed to 90-degrees; average peak torque was recorded and normalized to body mass. We used Pearson correlation coefficients to determine associations among hip and knee muscle strength. RESULTS: There were statistically significant positive relationships between all hip and thigh strength values of both limbs (Table 1). Correlations between knee EX and hip AB of the ACLR limb were between 0.640 and 0; the contralateral limb was between 0.583 and 0.769. Correlations between knee FL and hip AB of the ACLR limb were between 0.600 and 0.615; the contralateral limb was between 0.583 and 0.606. Correlations between knee EX and hip AD of the ACLR limb were between 0.579 and 0.726; the contralateral limb was between 0.574 and 0.754. Correlations between knee FL and hip AD of the ACLR limb were between 0.681 and 0.702; the contralateral limb was between 0.642 and 0.700. CONCLUSION: Statistically significant, moderate to strong, positive relationships among hip and thigh strength measures were found of both limbs about 7 months post ACLR. Relationships among hip and quadricep strength are all moderate to strong, appearing slightly weaker in the ACLR limb.