Study of Pain Management Techniques Following Anterior Cruciate Ligament Repair Surgery
Condition: Anterior Cruciate Ligament Reconstruction
Study type: Interventional
Phase: Phase 2/Phase 3

Summary: 
      Patients scheduled to undergo knee arthroscopy with anterior cruciate ligament repair with
      graft from the ipsilateral hamstrings and gracilis will be randomized to one of three groups.
      All patients will receive subsartorial saphenous nerve block. Along with this, Group 1 will
      receive perihamstring local anesthetic infiltration (Hamstring block), Group 2 will receive
      blockade of the anterior division of obturator nerve and Group 3 (control group) will receive
      sham injections of hamstrings and anterior division obturator nerve. All patients will
      receive co-analgesics for home discharge. The study will evaluate the efficacy of
      subsartorial saphenous nerve block alone or in combination with either hamstring block or
      obturator block with regards to postoperative analgesia especially the donor site pain and
      total analgesic consumption.
    

Detailed description: 
      Performance of arthroscopic knee repairs on day care basis necessitates adequate
      post-operative analgesia for successful home discharge since post-operative pain is known to
      be the commonest cause of unanticipated readmissions of day care patients. Early return to
      activity is also crucial to ensure adequate surgical outcomes. Anterior cruciate ligament
      (ACL) repair is commonly performed by arthroscopic approach with an ipsilateral
      hamstring-gracilis graft. This has shown to be superior to patellar tendon grafts with
      regards to pain and functional outcomes after surgery. Postoperative pain from the graft
      donor site and anterior knee pain form the surgery can lead to decreased range of motion and
      poor rehabilitation. A variety of regional anesthetic techniques are being tried for
      out-patient knee surgery like spinal adjuvants; intra and peri-articular injection, single
      injection and continuous blocks of the femoral and sciatic nerves, oral pills and
      cryoanalgesia. Opioid based analgesia with or without co-analgesics is not suited for dynamic
      pain relief since Aα and Aδ nerve fibres that carry pain are poorly inhibited by opioids
      while effectively inhibited by local anesthetics. Multimodal analgesic regimens work well for
      ambulatory surgeries especially when combined with regional analgesic techniques. Regional
      techniques decrease opioid consumption and hence opioid related side effects. Intra and
      peri-articular injections have a short duration of action compared to nerve blocks apart from
      the concerns of chondrotoxicity of intra-articular local anesthetics. Although femoral- and
      sciatic nerve blocks provide adequate analgesia, the weakness of the quadriceps and
      hamstrings can prevent early rehabilitative efforts and also pose a risk for patient falls
      following home discharge. Hence, novel regional techniques of analgesia like blocking the
      infrapatellar branch of saphenous nerve, graft site injections of local anesthetics through
      the arthroscopic sleeve and single injection adductor canal block have been tried. Isolated
      sensory block of the surgical and graft site without motor block is the Holy Grail in search
      for these ambulatory patients.

      Saphenous nerve, the terminal branch of femoral nerve supplies the majority of the knee
      joint. The femoral nerve exits the adductor canal and gives the terminal branch of saphenous
      nerve which lies between the Sartorius muscle and femoral artery in the sub-sartorial canal.
      Subsartorial canal block has been successfully utilized for forefoot surgery and knee
      arthroplasty but this has not been evaluated for ACL repairs. Saphenous nerve can be
      successfully blocked in the subsartorial canal without the risks of leg weakness but this
      alone is insufficient to provide analgesia to the graft donor site which is usually the
      gracilis tendon and the hamstrings tendon. Depositions of local anesthetics around the
      harvested muscle or blockade of the nerve supplying it are attractive strategies to decrease
      donor site pain but have not been explored for this purpose in a randomized fashion. The
      investigators hypothesize that the combination of any of the above two techniques to decrease
      donor site pain along with subsartorial saphenous nerve block can provide adequate analgesia
      in these patients. The anterior branch of the obturator nerve needs to be blocked since it
      supplies the gracilis muscle. To decrease the donor site pain, the saphenous nerve block can
      be combined with block of the anterior branch of obturator nerve. Alternatively, the
      saphenous nerve block can be combined with deposition of local anesthetic around the graft
      donor muscles. The extent to which the two techniques benefit the patients in terms of
      overall analgesia and the graft site analgesia has not been evaluated. With this background,
      the investigators want to compare the analgesic efficacy of subsartorial saphenous nerve
      block with either perihamstrings infiltration or blockade of the anterior division of
      obturator nerve in patients undergoing ACL reconstruction with ipsilateral autograft from
      gracilis and hamstring muscles.
    

Intervention name(s): Hamstrings block; Obturator block; Control group
Intervention type(s): Procedure; Procedure; Procedure
Intervention description(s): patients enrolled in the study will receive subsartorial saphenous nerve block in all the three groups. Patients in group 1 will receive perimuscular injections around the gracilis and semi-tendinosus muscles. The needle is redirected to the fascial plane between Sartorius and gracilis muscle after the sub-sartorial canal block where 7.5 ml of 0.5% ropivacaine is injected around the muscle. The needle is further advanced to the fascial planes between semimembranosus and semitendinosus and an additional 7.5 ml of 0.5% ropivacaine will be injected around the semitendinosus muscle. Following this a sham injection of 10mL of saline for the anterior division of obturator nerve will also be performed as in group 2 to ensure blinding.; Patients in group 2 will receive anterior division of obturator nerve block along with subsartorial canal block. After ensuring aseptic precautions, the saphenous nerve block is performed similar to that as in group 1. The anterior branch of obturator nerve will be visualised in the proximal thigh medial to femoral vessels between adductor longus and adductor brevis. A 22 gauge 90 mm PNS block needle will be inserted under ultrasound guidance to reach the anterior division of obturator nerve confirmed with neurostimulation followed by injection of 10 ml of 0.5% ropivacaine around the nerve. This group will receive sham injection of 15mL of saline around semitendinosus and semimembranosus as in group 1; The patients in group 3 will form the control group. After performance of the subsartorial saphenous nerve block, patients in group 3 will receive sham injections of saline for the obturator nerve block and the hamstrings block (perimuscular injections).
Other intervention name(s): perimuscular injections; anterior division obturator nerve block; saline group
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Double (Participant, Care Provider)
Primary purpose: Treatment
Keywords: anterior cruciate ligament repair, Obturator nerve block, Hamstrings graft, Ropivacaine,; Postoperative pain