Comparison Between 3 Solutions of Bupivacaine of Adductor Canal Block for Anterior Cruciate Ligament Reconstruction

Adductor canal block (ACB) is a new technique gaining acceptance as an alternative analgesic method of femoral nerve block (FNB) following knee surgery. The advantage of ACB is its dominant sensory nerve block effect. It preserves quadriceps muscle strength compared with the FNB. This will serve as potential gain for early rehabilitation and thereby functional outcome. Adequate direct injection of local anesthetic into the canal will block four nerves: the saphenous nerve, the nerve to the vastus medialis, the medial femoral cutaneous nerve, and the terminal end of the posterior division of the obturator nerve. Anterior cruciate ligament reconstruction (ACLR) is often associated with postoperative severe pain. Postoperative early rehabilitation is the primary focus to restore pre-injury status and is an essential part of the full recovery, especially that this rehabilitation extents over a 6 month period. Early elimination of pain is necessary to achieve this goal. However, there are no clear conclusive clinical reports defining the adequate analgesic volume-dosage of local anesthetic for ACB for postoperative ACL pain management. The investigators speculated that volume-dosage manipulation play key role in the effective of ACB for postoperative pain. The investigators conducted this prospective, randomized, observer-blinded trial to compare 3 combinations of volume and dosage of 0.25 % bupivacaine for US-guided ACB. The first aim of the investigation is to compare the analgesic effect of ACB 0.25% bupivacaine of the 3 doses as assessed by the visual analog scale (VAS) pain scores. The second aim were duration of analgesia, as defined by first demand for analgesia, and subsequent 24-h consumption. Physiotherapy tolerance and time to discharge were evaluated. Side effects were also assessed.