The purpose of this study is to determine whether periarticular multimodal drug injection (PMDI) would provide additional benefits in patients after total knee arthroplasty (TKA) for whom contemporary pain control protocols using the continuous femoral nerve block, intra-venous patient controlled analgesia (IV-PCA)and preemptive oral medications. We hypothesized that PMDI would reduce pain level and consumption of PCA and acute pain rescuer and would provide better functional recovery and patient satisfaction. We also hypothesized that the incidence of side effects and complications of the PMDI would be similar to the No-PMDI.

The preemptive multimodal approaches are regarded as a current standard pain management protocol. Recently, periarticular multimodal drug injection (PMDI) has been considered to be one of the most effective and important component in multimodal approaches. Because the contemporary pain management protocol using the regional anesthesia, continuous femoral nerve block (FNB) and intravenous patient-controlled analgesia (PCA) has been proved significantly improved analgesic effects itself, little information whether the PMDI would provide additional pain relief under this pain management protocol is available. Also, because the safety of the high dose local anesthetics and narcotics has not been clarified, a selective application should be considered to patients who were expected to show better analgesia if there were certain patient related factors to predict the additional pain relief effect of the PMDI. Thus, this prospective double-blind randomized study was conducted to determine whether PMDI would provide additional benefits in patients after total knee arthroplasty (TKA) for whom contemporary pain control protocols using the continuous femoral nerve block, IV-PCA and preemptive oral medications in terms of pain relief, consumption of PCA and acute pain rescuer, patients satisfaction, functional recovery, side effects and complications.

Inclusion Criteria:

• Diagnosis of primary osteoarthritis
• Scheduled for elective total knee arthroplasty
• Signed written informed consent
• Spinal anesthesia

Exclusion Criteria:

• Patients refusing consents
• inability to use the outcome assessment tools
• Contraindications to regional anesthesia
• severe cardiovascular disease
• allergy or contraindication to drugs used in this study
• pre-existing neurologic disease including psychiatric disorder
• drug abuser

within postoperative 30 days