Quadriceps muscle atrophy may persist 2 years after ACL surgery in elite athletes
Key takeaways:
- Among elite football players, atrophy may persist in the quadriceps and gastrocnemius muscles 2 years after ACL surgery.
- Results highlight the importance of isolated muscle strengthening after ACL surgery.
A study of NCAA Division I football players revealed persistent atrophy in the quadriceps and gastrocnemius muscles 2 years after ACL reconstruction despite full return to play.
“Our findings highlight the ongoing challenge of quadriceps dysfunction following ACL reconstruction, even among athletes receiving high-level medical care,” Bryan C. Heiderscheit, PT, PhD, FAPTA, Frederick Gaenslen Professor in Orthopedics, vice chair of research in the department of orthopedics and rehabilitation and director of Badger Athletic Performance and UW Health Runners’ Clinic at the University of Wisconsin-Madison, told Healio. “We also identified deficits in the gastrocnemius muscle, though not in the soleus, suggesting that ACL reconstruction may influence other muscle groups involved in tibial anterior translation.”
Heiderscheit and colleagues performed a secondary analysis of a multicenter prospective cohort study of 30 NCAA Division I-football players who underwent primary, unilateral ACL reconstruction with a mean follow-up of 27.9 months.
According to the study, one athlete (3%) received an allograft, two athletes (7%) received quadriceps tendon autograft, 22 athletes (73%) received bone–patellar tendon–bone autograft and five athletes (17%) received hamstring tendon autograft.
Heiderscheit and colleagues used MRI and machine learning to assess muscle volume from 38 lower extremity muscles. Muscle volumes were compared with the healthy limb to quantify atrophy.
Heiderscheit and colleagues found the vastus intermedius, vastus lateralis and vastus medialis muscles in the surgical limbs had the greatest muscle volume deficits compared with healthy limbs. They also found the gastrocnemius muscles in the surgical limbs had significant muscle volume deficits compared with healthy limbs. However, they found no significant atrophy in the rectus femoris and soleus muscles compared with healthy limbs.
“Gastrocnemius muscle deficits were also found in this exploratory analysis, indicating the potential need to emphasize plantarflexion strengthening after an ACL injury,” Heiderscheit and colleagues wrote.
They noted the combined fibularis muscles were the only muscles in surgical limbs to have significantly greater muscle volumes compared with healthy limbs.
“These insights reinforce the need for rehabilitation strategies that prioritize quadriceps recovery while also addressing the role of other muscle groups, such as the gastrocnemius,” Heiderscheit said. “Additionally, the use of machine-learning algorithms facilitated large-scale muscle volume analysis, demonstrating its potential as a valuable tool for studying muscle adaptations across various orthopedic and sports-related injuries.”
Perspective
Back to TopA new study, funded by the NFL, from Naoaki Ito, PT, DPT, PhD; Bryan C. Heiderscheit, PT, PhD; and the HAMIR investigators used innovative machine-learning algorithms to measure muscle volumes of 38 lower extremity muscles in 30 NCAA Division I football players after ACL reconstruction, rehabilitation and return to play. At an average of 2.4 years after surgery, the uniarticular quadriceps muscles demonstrated significant atrophy compared with the uninjured leg (limb symmetry in the low 90%). Three-quarters of the players had ACL reconstruction with autografts from the knee extensor mechanism (bone-patellar tendon-bone autograft, n = 22; quadriceps tendon autograft, n = 2). Those who had ACL reconstruction with hamstring autograft (n = 5) had semitendinosus atrophy limb symmetry of only 56% in addition to quadriceps atrophy.
Quadriceps dysfunction persists after ACL injury and reconstruction. This study highlights the particular symbiosis between the ACL and the quadriceps muscles. Early after ACL rupture, there is activation failure (arthrogenic inhibition) of the quadriceps. Perhaps the high threshold motor units affected never fully recover. This study underscores the need for continued focus on the quadriceps rehab after ACL injury and provide more impetuous for continued investigation into causes and rehabilitation strategies.
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