2015 ISAKOS Biennial Congress ePoster #1321

MRI Study of Changes in Muscle Volume in ACL Reconstructed Knees Following Conventional or Accelerated Rehabilitation Programmes

Jesús Alfaro-Adrián, MD, DPhil(Oxon), Pamplona, Navarra SPAIN
Igor Setuain, PhD, Pamplona SPAIN
Fernando Idoate, MD, PhD, Pamplona SPAIN
Mikel Izquierdo, Prof., Pamplona SPAIN

Clínica San Miguel / Sports Medical Study and Research Center, Pamplona, Navarra, SPAIN

FDA Status Not Applicable

Summary: Subjects following accelerated rehabiitation programmes exhibit greater muscle force despite persisiting mucle size reduction




There is some evidence that in the short term following an accelerated rehabilitation program after ACL reconstruction there is greater muscle force output. However it is still controversial if better muscle performance would be associated with a larger muscle cross sectional area (CSA) in thigh musculature one year after original reconstruction.


To analyze the evolution of CSA of quadriceps and hamstring muscles in a sample of recreational athletes following two different rehabilitation programs: conventional (15) and accelerated (14), before and one year after having undergone ACL surgical reconstruction with quadruple autologus hamstring graft.

Material And Methods

29 athletes underwent MRI studies before and 12 months after ACL reconstruction. CSA was calculated (mm2), on Quadriceps (Q), Biceps femoris (BF), Semitendinous, (ST) Semimenbranous (SM) and Gracilis (GR) muscles, at 30, 50 and 70% of the femur´s length level. All the surgical interventions were performed by the same surgeon and following the same technique. Isokinetic knee joint flexo-extension torque evaluations (N.m) (Cybex – Human Norm© CA. USA) were also performed in the same time points at an angular velocity of 180º*sec


Significant (p< 0.05) muscle CSA reductions (ST at 50% and GR at 70% levels in the reconstructed limb before and one year after ACL reconstruction) were observed in both treatment groups: [mean± SD: ST: 861.9 ± 278.97 vs. 625.81 ± 208.35; 95% CI: 51,94 – 420.25 GR:131.50 ± 87.76 vs 50.72 ± 79.90; 95% CI: 18.0 – 143.54 mm2 ] and [ST: 807.62 ± 178.06 vs 630.56 ± 158.22; 95% CI: 46.20 – 307.91 GR: 165.24 ± 130.94 vs 53.13 ± 60.40; 95% CI: 29.56 – 194,64 mm2 ]in conventional and accelerated treatment groups respectively. There were no significant differences between groups at any of the analyzed variables.
With respect to muscle isokinetic performance, subjects allocated in the accelerated rehabilitation group, demonstrated significantly (p< 0.05) greater knee flexion torque in their reconstructed limbs in comparison to conventionally rehabilitated subjects [mean± SD: 186.29 ± 37.96 vs 141.23 ± 34.79 N.m accelerated and conventional groups respectively] that were not present before ACL reconstruction [ mean± SD: 142.38 ± 38.54 vs 141.95 ± 52.04 N.m accelerated and conventional groups respectively]


atrophy of the implicated musculature (ST and GR) related to the surgical reconstruction present in both groups persisted in the reconstructed limb 1 year after ACL reconstruction. Surprisingly, subjects following an accelerated rehabilitation protocol exhibited greater muscle force despite persisting muscle size reduction.
It seems that selective retraining of hamstring musculature (accelerated program) after ACL reconstruction is necessary in order to compensate for the observed muscle atrophy process.
The monitorization of the strength level of hamstring muscles during the rehabilitation process would aid to reduce the commonly observed hamstring muscle strains episodes when returning to sport after ACL reconstruction.