Abstract
Background
Continuous epidural anesthesia or femoral nerve block has decreased postoperative pain after total knee arthroplasty to some extent. Although the established efficacy of these pain relief method, some adverse events such as hematoma or muscle weakness are still problematic. Intraoperative local infiltration of analgesia (LIA) has accepted as a promising pain control method after total knee arthroplasty. The safety and efficacy of LIA has been reported, although there are still limited evidence about the effect of LIA on quadriceps function and recovery of range of motion in early post-operative phase. The purpose of this study is to compare the quadriceps function and range of motion after TKA between the LIA with continuous epidural anesthesia and continuous epidural anesthesia alone.
Methods
Thirty patients with knee osteoarthritis who underwent primary TKA were included in this study. Patients who took anticoagulants were treated continuous epidural anesthesia alone (n=11) and the other patients were treated with LIA with continuous epidural anesthesia (n=19). A single surgeon at our department performed all surgeries. Surgical procedure and rehabilitation process was identical between two groups. Before the implantation, analgesic drugs consisting of 20 ml of 0.75 % ropivacaine and 6.6 mg of dexamethasone were injected into the peri-articular tissues. In each group, fentanyl continuous epidural patient-controlled analgesia (PCA) was also used during 48-h post-operative period. Knee flexion and extension angle were evaluated before surgery, post-op day 3, 7, 10 and 14. The quadriceps function was evaluated by quadriceps peak torque at 30° and 60° flexion using VIODEX. The peak torque was recorded preoperatively, day 14 and 3 month after surgery. The difference between two groups was analyzed by Mann Whitney U-test using Prism 6, a statistical software.
Results
LIA group showed better postoperative flexion angle until day 7 (Fig. 1). Then the discrepancy became smaller and came to the same degree at day14. The peak torque at 30° and 60° flex is higher in LIA group compared to epidural anesthesia alone. The LIA group showed less peak torque decrease at 2 weeks after surgery than epidural anesthesia alone group (Fig. 2, 3). No adverse events such as were observed in each group.
Discussion
This paper demonstrated that LIA in addition to the continuous epidural anesthesia after TKA provides better quadriceps function and early recovery in knee range of motion. In this study we also used continuous epidural anesthesia, thus this study can not evaluate the stand alone LIA effects on quadriceps function and range of motion recovery. Furthermore the patients were not randomly assigned in this study, this might be another limitation of this study. In conclusion, LIA provide better quadriceps function and early recovery of range of motion in addition to the pain relief.
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