Anterior cruciate ligament reconstruction is a routine surgical procedure. Traditional femoral/sciatic block combinations effectively reduce postoperative pain, but results in considerable motor blockade. The investigators aimed to evaluate postoperative pain relief and the degree of motor block with block combinations of femoral nerve (FEM) and obturator [posterior branch] nerve (ONP), versus saphenous nerve (SAPH) and ONP, versus placebo blocks with isotonic saline. All patients received standard patient controlled analgesia with morphine.Randomized, placebo-controlled and double-blinded clinical trial. Following IRB approval, 81 patients were planned to be randomized to one of three USG block combinations: Active FEM+ONP, active SAPH+ONP or no active blocks (sham blocks) Ropivacaine 0.75% was used for all active blocks following induction of general anaesthesia [propofol-remifentanil, laryngeal mask airway]. Primary outcome measure: Localized PACU pain scores (AUC) 0-6 hours postoperatively at rest.

Secondary outcome measures: Opioid consumption, opioid related side effects, PACU time, motor abilities of daily living scores [modified Barthel/100 index], perceived ill health [Short form-8] scores and degree of motor blockade [Jensen- Børglum motor test].

Inclusion Criteria:

• Age ≥ 18 years.
• Isolated primary ACL reconstruction in general anaesthesia with hamstring graft.
• ASA 1-3.
• Written and informed consent to study protocol.

Exclusion Criteria:

• ACL reconstruction with patellar tendon graft
• Uncooperative patients.
• Patients that do not understand or speak danish.
• Daily use of opioids equivalent to > 40 mg morphine.
• Allergic to Ropivacaine.
• Alcohol abusers
• Contraindications to general anaesthesia.
• Pregnancy.