The incidence of development of motor blockade by ropivacaine is concentration dependent, and most studies regarding the continuous FNB after total knee arthroplasty used 0.2% to 0.3%ropivacaine

Continuous Femoral Nerve Block versus Intravenous Patient Controlled Analgesia for Knee Mobility and Long-Term Pain in Patients Receiving Total Knee Replacement: A Randomized Controlled Trial

Objectives. To evaluate the comparative analgesia effectiveness and safety of postoperative continuous femoral nerve block (CFNB) with patient controlled intravenous analgesia (PCIA) and their impact on knee function and chronic postoperative pain. Methods. Participants were randomly allocated to receive postoperative continuous femoral nerve block (group CFNB) or intravenous patient controlled analgesia (group PCIA). Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) scores for knee and incidence of chronic postoperative pain at 3, 6, and 12 months postoperatively were compared. postoperative pain and salvage medication at rest or during mobilization 24 hours, 48 hours, and 7 days postoperatively were also recorded. Results. After discharge from the hospital and rehabilitation of joint function, patients in group CFNB reported significantly improved knee flexion and less incidence of chronic postoperative pain at 3 months and 6 months postoperatively (P < 0.05). Analgesic rescue medications were significantly reduced in patients receiving CFNB (P < 0.001 and P = 0.031, resp.). Conclusion. With standardized rehabilitation therapy, continuous femoral nerve block analgesia reduced the incidence of chronic postoperative pain, improved motility of replaced joints, and reduced the dosages of rescue analgesic medications, suggesting a recovery-enhancing effect of peripheral nerve block analgesia.

Reduction of the incidence of development of venous thromboembolism by ultrasound-guided femoral nerve block in total knee arthroplasty

Background

Venous thromboembolism (VTE) and the subsequent development of pulmonary embolism (PE) is a major cause of post-operative mortality in total knee arthroplasty (TKA). We evaluated whether the addition of an ultrasound-guided femoral nerve block with general anesthesia affected the incidence in the development of VTE following TKA.

Methods

This was a retrospective non-randomized comparative study with patients assigned to groups based on the surgery date (pre-femoral nerve block versus post-femoral nerve block periods). All anesthesia and medical records of the patients who had undergone computer-navigated TKA in our facility between January 2009 and March 2010 were retrospectively reviewed.

Results

Forty patients were identified; 15 patients underwent computer-navigated TKA under general anesthesia alone (Group G) and 25 patients underwent surgery under general anesthesia combined with ultrasound-guided femoral nerve block (Group F). The incidence of development of VTE post-operatively was significantly lower in Group F (P = 0.037). Logistic regression analysis identified the use of a femoral nerve block as the most significant variable correlating with the incidence of post-operative development of VTE, and the odds ratio for VTE development in Group G was 3.12 (95% CI, 0.57-20.56).

Conclusions

We suggest the possibility that the addition of a femoral nerve block on general anesthesia may reduce the incidence of the development of VTE following TKA.