Obturator Nerve Block for Postoperative Pain Control After Total Knee Arthroplasty: Case Series and Literature Review

For postoperative analgesia following total knee arthroplasty, the adductor canal block and the injection of local anesthetic between the popliteal artery and the posterior capsule of the knee (IPACK) are among the most frequently utilized regional anesthetic techniques. The adductor canal block specifically targets the anterior knee compartment, while the IPACK technique aims to block the sensory innervation to the posterior knee, thereby providing effective pain control. These interventions are commonly employed to minimize opioid consumption and improve overall pain management outcomes in the immediate postoperative period. According to the existing literature, the obturator nerve block is less commonly employed compared to other peripheral nerve blocks. The obturator nerve, a mixed nerve, plays a role in the innervation of the knee in conjunction with the femoral and sciatic motor nerves. In the present study, three patients who underwent total knee arthroplasty under subarachnoid anesthesia, supplemented with an adductor canal block for postoperative analgesia, reported moderate-to-severe pain in the immediate postoperative period. Subsequent effective analgesia was achieved through the administration of a single-shot obturator nerve block. The outcomes were highly favorable, demonstrating a significant improvement in pain control. The patients experienced adequate analgesia, thereby illustrating the efficacy of the obturator nerve block in managing pain following total knee arthroplasty, without impairing ambulation, and facilitating the early initiation of rehabilitation therapy. Based on our experience, the obturator nerve block is an effective analgesic technique that can be employed either in combination with other peripheral nerve blocks or as a rescue strategy when patients, despite having undergone other regional analgesia techniques, continue to report moderate-to-severe pain in the immediate postoperative period following total knee arthroplasty. In contrast to the femoral nerve block, which induces a broad motor blockade and substantially impairs ambulation, the obturator nerve block may cause motor impairment limited to thigh adduction, which is unlikely to significantly affect the patient's ability to ambulate.