A multimodal technique was developed to improve post-operative pain control after total knee arthroplasty. Femoral nerve blocks [3
] and epidural anesthesia [4
] have been reported to control pain with good efficacy. However, these procedures require a well-trained physician, and there are some complications that could result from these procedures. Sharma et al. reported the rate of femoral neuropathy/neuritis after femoral nerve block has been estimated to be approximately 0.59% [15
The intraoperative periarticular injection technique for reduction of post-operative pain control following total knee arthroplasty has been reported and has demonstrated good results.
Vendittoli et al. reported that perioperative periarticular infiltration with ropivacaine, ketorolac, adrenaline, and injection with ropivacaine (150
mg) on the first after the operative day showed a reduction in narcotic requirements at 48 hours after the operation with minimal side effects to patients when compared to the control group [7
Parvataneni et al. studied the efficacy of local intraoperative injection with a combination of 0.5% bupivacaine, morphine sulfate, epinephrine, methylprednisolone acetate, cefuroxime, and normal saline in total hip and total knee replacement patients. This study demonstrated a reduction in the pain score at 72 hours after the operation, a decreased hospital stay, and increased satisfaction scores when compared with the control group [8
Busch et al. reported a decreased consumption of patient-controlled analgesia (PCA) at 12 hours after the operation and a lower pain score in total knee replacement patients who received a perioperative, periarticular injection with ropivacaine, ketorolac, epimorphine, normal saline, and epinephrine compared with patients who did not receive an injection [11
In our study, we collected data from 0–96 hours that was the time when the patients had PCA. Data from our study are in agreement with previous reports on the efficacy of periarticular injection. However, our study objective was to evaluate the efficacy of bupivacaine alone in reducing post-operative pain when used for perioperative, periarticular injection. Our study demonstrated that bupivacaine injection alone, without other drugs, significantly reduced morphine consumption at 6 hours after the operation. However, visual analog scale scores for pain were not different between the control and bupivacaine-injection groups. This may be because morphine that the control group patients received which was more than the other groups via PCA obscured VAS scores. So, the result confirmed that the patients used PCA machine properly when they started to feel pain. Other reason that this study lacks having an effect on the VAS scores may be the issue of dosing that the previous study used higher dose of anesthetic agent than our study.
We did not observe complications from a periarticular bupivacaine injection in our study, which is consistent with previous periarticular injection studies. Thus, our study adds to evidence that periarticular injections are safe when used in knee replacement procedures, in which post-operative infection and wound complications are the most prominent complications.