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Updated: Jul 13, 2026
Early Weight-Bearing Rehabilitation Protocol After Anterior Cruciate Ligament Reconstruction
Published on: March 1, 2024
Heterogeneity of quadriceps muscles atrophy following anterior cruciate ligament reconstruction: A longitudinal MRI
Kate B Berg1, Tamera N Mistry1, Mark A Lyle2
1Georgia State University, Department of Physical Therapy, USA.
Objectives:
This study used MRI to longitudinally assess the differences in atrophy among individual quadriceps muscles and the association between muscle volume and strength recovery following ACL reconstruction (ACLR).
Design:
Longitudinal within-subject.
Setting:
Laboratory.
Participants:
13 subjects with unilateral ACLR.
Main Outcome Measures:
MRI and isokinetic strength of bilateral quadriceps muscles were acquired at 6 months and 1 year post-ACLR. The volumes of the 4 quadriceps muscles (vastus medialis, VM; vastus lateralis, VL, vastus intermedius, VI; rectus femoris, RF) were measured. The degree of atrophy for each muscle was calculated as % difference of the uninjured leg.
Results:
At both time points, all 4 quadriceps muscles of the ACLR legs were significantly smaller than the uninjured legs (P < 0.001), with greater atrophy in VM/VL than VI/RF (P ≤ 0.045). None of the 4 quadriceps muscles of the ACLR legs showed significant volumetric changes over time (P > 0.171). Quadriceps volume and strength recovery in the ACLR legs were not significantly correlated (r = 0.50, P = 0.09).
Conclusions:
Persistent quadriceps atrophy was found 1 year post-ACLR with greater atrophy in VL/VM than VI/RF. Limited and heterogeneous muscle hypertrophy over time and the lack of strong association between hypertrophy and strength recovery highlight the need for rehabilitation promoting both morphological and functional recovery.