Inadvertent motor blockade in tibial and common peroneal nerve distribution following adductor canal block for ACL repair

NMUH Staff Publications

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<span style="font-size: 10pt;"><span style="color: #4a4a4a; font-family: Lato, "Helvetica Neue", Helvetica, Arial, sans-serif; text-decoration-color: initial;">Background and Aims: Adductor canal block (ACB) has recently emerged as an alternative to femoral nerve block for pain control after various surgical procedures of the knee including knee arthroplasty, arthroscopy and anterior cruciate ligament (ACL) reconstruction.We report a case of motor popliteal blockade (tibial and common peroneal nerve) following an ACB for ACL reconstruction. Methods: A 21 year old female medical student was operated for ACL reconstruction under general anaesthetic. and an ACB. The block was performed with 20mls of 0.175% Levobupivacaine under ultrasound guidance. Patient had good sensory blockade in the saphenous nerve distribution. However, in the postoperative period, the patient reported weakness of dorsi and plantar flexion of the foot. Clinical examination also revealed sensory loss in the popliteal distribution. Quadriceps function remained intact. The patient was admitted for observation. Patient regained full motor power 12 hours after the procedure and sensation in 20 hrs. She was then discharged the following day after commencing physiotherapy. Results: Our patient developed transient blockade of the common peroneal and tibial nerve.We believe that thiswas due to the local anaesthetic as therewas complete recovery in 20 hours. A proportion of local anaesthetic might have travelled into popliteal compartment leading to blockade of the nerves here. Conclusions:We recommend limiting the volume of local anaesthetic used for adductor canal block to decrease the chance of spread into popliteal compartment. We also recommend warning patients about possible risk of motor blockade while obtaining informed consent for an adductor canal block.</span> [Conference abstract]</span>