Quadriceps function relates to muscle size following ACL reconstruction

Abstract

ABSTRACT:It remains unclear what role reduced volume and cross-section area (CSA) of individual quadriceps muscles may play in persistent quadriceps weakness and more global dysfunction following ACL reconstruction (ACLR). The purpose of this investigation was to establish the relationship between cross-sectional area of the quadriceps muscle group and measures of knee related and quadriceps function following ACLR. Thirty participants with a history of primary, unilateral ACLR experiencing persistent quadriceps activation failure participated in this cohort study. Clinical factors including International Knee Documentation Committee (IKDC) score, normalized knee extension MVIC torque (Nm/kg) and quadriceps central activation ratio (CAR, %) were assessed in addition to CSA. Quadriceps CSA was measured via magnetic resonance imaging (MRI; Siemens Avanto 1.5T). Quadriceps CSA (cm 2 ) and quadriceps volume (cm 3 ) as well as individual muscle estimates were identified within a 10 cm mid-thigh capture area. Pearson's product-moment correlation coefficients (r) established relationships between CSA and all other variables. Stepwise linear regression established which CSA factors were able to successfully predict clinical factors. Knee extension MVIC torque was strongly correlated with Vastus Intermedius (VI; r ¼ 0.857, p < 0.001) CSA as well as partial VI (r ¼ 0.849, p < 0.001) and quadriceps (r ¼ 0.830, p < 0.001) volume. Partial VI (r ¼ 0.365, p ¼ 0.047) volume was weakly correlated with IKDC score. Knee extension MVIC torque was strongly predicted using VI CSA alone (R 2 ¼ 0.725) or in combination with Vastus Medialis CSA (VM; R 2 ¼ 0.756). Statement of Clinical Significance: Atrophy of the VI and VM muscles negatively impacts knee extension strength following ACLR. ß

Contribution of Neuromuscular Factors to Quadriceps Asymmetry After Anterior Cruciate Ligament Reconstruction

“…27,32,33,35À37 Whereas we did not directly analyze these possibilities, several authors using imaging technologies found that patients with ACLR experienced reduced total muscle volume 38,39 and anatomic CSA. 40 Recently, Kuenze et al 41 used magnetic resonance imaging and custom-written software to quantify individual variations in quadriceps muscle volume and reported that reductions in the vastus intermedius muscle belly were most strongly related to a decline in isometric quadriceps force production. We examined this characteristic of muscle using classic muscle-mechanics relationships to gain insight into the underlying morphologic changes, which is a costeffective technique for clinicians to employ.…”

Unilateral Quadriceps Strengthening With Disinhibitory Cryotherapy and Quadriceps Symmetry After Anterior Cruciate Ligament Reconstruction

“…Q uadriceps weakness and activation failure commonly persist beyond the return to physical activity after anterior cruciate ligament reconstruction (ACLR) because of a number of underlying factors, including muscle atrophy 1 and persistent muscle inhibition. 2 Despite this concerning clinical finding, many individuals successfully return to recreational and competitive physical activity after ACLR.…”

Quadriceps Muscle Size Following ACL Injury and Reconstruction: A Systematic Review

“…Quadriceps weakness is attributed to alterations in muscle morphology, and neurological drive . One of the hypothesized contributors to quadriceps function is quadriceps size . The advent of computerized tomography (CT) and magnetic resonance imaging (MRI) technologies permit direct evaluation of post‐operative changes in muscle size calculated as either a cross‐sectional area (CSA) or a muscle volume, which provide targeted and standardized estimates of affected musculature .…”

“…Quadriceps weakness is attributed to alterations in muscle morphology, [24][25][26] and neurological drive. 3,15,27 One of the hypothesized contributors to quadriceps function is quadriceps size.…”