In this prospective, assessor-blinded, single-surgeon clinical trial, the goal was to validate the efficacy of PAI in aACLR surgery with a reduced opioid dose, while achieving similar pain relief with few adverse events. 300 patients who had undergone aACLR were randomly allocated to receive either a PAI or nPAI group. The primary outcome parameters were visual analogue scale (VAS) scores and cumulative morphine dose, through time. Secondary outcome parameters included drug-related adverse events.

Inclusion Criteria:

• 1) Patients 18 years or older who had undergone a-ACLR with or without meniscus procedure for anterolateral instability of the knee; 2) agree to participate in this study and to be randomly allocated to either or peri-articular injection protocol and have signed an informed consent.

Exclusion Criteria:

• 1) patients with other concomitant injuries such as other ligamentous injury or fracture; 2) Allergy to any of the medication used in either protocol; 3) patient with history of the chronic pain 4) preoperative chronic opioid-dependent patients (exceeding 50 mg oral morphine equivalence per day at time of recruitment); 5) refuse to participate in this study.

Concerning the patient's privacy