Objective: Femoral nerve block has been proven as an effective analgesia for total knee arthroplasty (TKA). Delayed recovery from nerve block can result in serious complication during postoperative period. This prospective, single-center,
observational study investigated the incidence in delayed recovery from femoral nerve block more than 24 hours postoperatively.
Material and Method: Two hundred and forty patients with femoral nerve block as part of anesthesia plan for elective
unilateral TKA were recruited into study. Participants were assessed for sensory or motor impairment lasting longer than 24 hours post operation. Factors associated with delayed recovery form femoral nerve block were analyzed.
Results: Five patients (incidence = 2.08%) reported sensory or motor impairment more than 24 hours post operation. All of
the patients could ambulate within 4 days post operation without permanent nerve injury or serious complication. Higher
dose of local anesthetic agent using for femoral nerve block showed association with the delayed recovery (p-value = 0.01).
Conclusion: This study demonstrated 2.08% incidence in delayed recovery from femoral nerve block. High concentration
and dose of local anesthetic agent may lead to fall during early ambulatory period.

Keywords: Neurological complication, Femoral nerve block, Total knee arthroplasty