Despite advances in surgery and rehabilitation, the return to sport after anterior cruciate ligament (ACL) reconstruction surgery remains a major challenge.

challenge. Among the objective criteria retained, the isokinetic muscle strength assessment is an increasingly practiced evaluation and it is recommended to carry out follow-ups at 3-4 months (intermediate) and at 6-8 months (final) after surgery. However, the factors associated with muscle imbalance are uncertain and the threshold values of the intermediate isokinetic strength test (3-4 months) are inconsistent. In a retrospective analysis, the investigators aim to assess the predictive criteria for muscle imbalance after ACL reconstruction surgery.

The investigators aim to retrospectively studied all sports patients who had a muscle evaluation at 3-4 months and 6-8 months after anterior cruciate ligament (ACL) reconstruction surgery since January 2016. The objective criterion were based on the international guidelines for muscle imbalance after ACL surgery and return to sport, as a muscle deficit of less than 20% on knee extensor muslces and less than 10% on knee flexor muscles of the operated knee (vs. healthy).

The investigators will study the predictive analysis of the intermediate muscle strength test to predict the risk of muscle imbalance on the final isokinetic muscle strength assessment. The investigators will also study the individual, injury and surgical criteria associated with muscle imbalance.

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 3-4 months and 6-8 mnths after surgery respectively
• Patient who received the information form

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

All sports patients included in the sport medicine follow-up protocole with isokinetic muscular assessment at 3-4 months and 6-8 months after ACL reconstruction surgery since January 2016