Changes in the Force-velocity Relationship of Knee Muscles After ACL Reconstruction

Changes in the Force-velocity Relationship of Knee Muscles After ACL Reconstruction

Anterior cruciate ligament (ACL) tear is a frequent and devastating injury in sport, especially in pivoting-contact disciplines. In many cases, athletes will undergo an ACL reconstruction (ACL-R) for recovering knee stability, preventing further injuries and returning to sport (RTS). Among the criteria for RTS, knee muscle strength is the most used objective criteria and especially the symmetry of knee flexors and/or extensors between the operated and uninjured knee.

Isokinetic testing of knee muscle strength is considered as a reference for knee muscle testing during the follow up stages after ACL-R. This evaluation allows to measure the strength (torque) of knee flexors and extensors at several angular velocities. However, there is no relevant litterature about the force-velocity (Fo-v) relationship of knee flexors and extensors after ACL-R.

The present study aimed to evaluate and test the differences between the Fo-v relationship parameters between the operated and uninjured knees at 4 months and 8 months after ACL-R, using the 2-points method with isokinetic testing. Also, the investigators aimed to test the impact of the type of surgery (patellar tendon autograft vs. hamstring tendon autograft) on the Fo-v relationship after ACL-R

Inclusion Criteria:

• Patients who have had an ACL reconstruction surgery (isolated or associated with other meniscal or ligamentary surgery)
• Patient included in the sport medicine follow-up protocole with intermediate and final isokinetic muscular assessment at 4 months and8 months after surgery respectively
• Patients who completed both tests at the 60°/s and 240°/s velocities

Exclusion Criteria:

• Patient who did not participate in all follow-up consultations and isokinetic muscular assessments
• Cognitive or sensory impairment making it impossible to understand the information form
• Neurological, traumatic or osteoarticular history responsible for muscle imbalance prior to surgery