Quadriceps Neuromuscular and Physical Function After Anterior Cruciate Ligament Reconstruction

Abstract

Context Persistent neuromuscular deficits in the surgical limb after anterior cruciate ligament reconstruction (ACLR) have been repeatedly described in the literature, yet little is known regarding their association with physical performance and patient-reported function. Objective To describe (1) interlimb differences in neuromuscular and functional outcomes and (2) the associations of neuromuscular outcomes with measures of physical and knee-related patient-reported function. Design Cross-sectional study. Setting Laboratory. Patients or Other Participants Thirty individuals after primary, unilateral ACLR (19 males; age = 21.5 years [range, 14–41 years]; 8 months [range = 6–23 months] postsurgery). Main Outcome Measure(s) Knee-extensor isometric and isokinetic peak torque was measured with an isokinetic dynamometer. Cross-sectional area (CSA) was measured bilaterally for each of the quadriceps muscles via magnetic resonance imaging. We measured quadriceps central activation bilaterally via the superimposed-burst technique. Physical performance (single-legged hop tests, step length via spatiotemporal gait analysis) and patient-reported outcomes (International Knee Documentation Committee questionnaire and Knee Injury and Osteoarthritis Outcome Score Sport and Recreation subscale) were also recorded. We conducted Wilcoxon signed rank tests to identify interlimb differences. Spearman ρ correlation analyses revealed associations between limb symmetry and neuromuscular and functional outcomes, as well as with patient-reported function. Results Deficits in the surgical limb as compared with the nonsurgical limb were present for all outcomes (P values < .05). Greater single-legged hop-test symmetry (83%) was significantly correlated with greater symmetry in knee-extensor isometric (63%; rs = 0.567, P = .002) and isokinetic (68%; rs = 0.540, P = .003) strength, as well as greater cross-sectional area of the vastus medialis (78%; rs = 0.519, P = .006) and vastus lateralis (82%; rs = 0.752, P < .001). A higher International Knee Documentation Committee questionnaire score (82.2) was significantly correlated with greater symmetry in knee-extensor isokinetic strength (rs = 0.379, P = .039). Conclusions Although deficits were observed in the surgical limb for all neuromuscular measures, greater symmetry in the size and strength of the quadriceps, rather than activation, was more strongly associated with physical performance after ACLR. Greater symmetry in strength was also more strongly associated with patient-reported function.

Rationale for a Parsimonious Measure of Subjective Knee Function Among Individuals With Anterior Cruciate Ligament Reconstruction: A Rasch Analysis

“…11,34 However, we did not observe evidence of association between subjective knee function and quadriceps strength symmetry, which has been described. 12,35 Although relationships between subjective and objective knee function can be influenced by the magnitude of impairment, individuals with ACLR in our sample appeared to demonstrate impairments in quadriceps strength, quadriceps strength symmetry, SLH distance, and SLH symmetry consistent with those in the literature. 36 The lower self-reported current activity level among the ACLR group could partially explain the observation of objectively measured impairments, although these relationships are unclear in the literature.…”

Gait asymmetries are exacerbated at faster walking speeds in individuals with acute anterior cruciate ligament reconstruction

“…Future research is needed, however, to elucidate the biomechanical factors associated with mid‐ and late‐ stance vertical GRF alterations and how these aberrant gait mechanics are associated with patient outcomes and/or knee joint health. Furthermore, although not measured here, interlimb differences in spatiotemporal parameters may partly contribute to these GRF asymmetries as recent findings have shown patients approximately 8 months post‐ACL reconstruction walk with asymmetrical step lengths 42 . Future studies should consider evaluating the contributions of spatiotemporal parameters to loading characteristics in those with ACL reconstruction.…”

“…Furthermore, although not measured here, interlimb differences in spatiotemporal parameters may partly contribute to these GRF asymmetries as recent findings have shown patients approximately 8 months post-ACL reconstruction walk with asymmetrical step lengths. 42 Future studies should consider evaluating the contributions of spatiotemporal…”

Proprioception recovery after anterior cruciate ligament reconstruction: Isokinetic versus dynamic exercises

“…Many authors have monitored the recovery of proprioception in patients after ACL reconstruction. [12][13][14][15][16][17][18] The speed of recovery was determined, among other things, by the type of proprioceptive re-education exercises used. However, the different results regarding the recovery time of proprioception in these patients can be explained by differences in the characteristics of the examined sample in terms of age, sex and level of physical activity.…”