Linda T. Le

Ambulatory continuous femoral nerve blocks decrease time to discharge readiness after tricompartment total knee arthroplasty: a randomized, triple-masked, placebo-controlled study.

Background:The authors tested the hypotheses that, compared with an overnight continuous femoral nerve block (cFNB), a 4-day ambulatory cFNB increases ambulation distance and decreases the time until three specific readiness-for-discharge criteria are met after tricompartment total knee arthroplasty. Methods:Preoperatively, all patients received a cFNB (n = 50) and perineural ropivacaine 0.2% from surgery until the following morning, at which time they were randomly assigned to either continue perineural ropivacaine or switch to perineural normal saline. Primary endpoints included (1) time to attain three discharge criteria (adequate analgesia, independence from intravenous analgesics, and ambulation of at least 30 m) and (2) ambulatory distance in 6 min the afternoon after surgery. Patients were discharged with their cFNB and a portable infusion pump, and catheters were removed on postoperative day 4. Results:Patients given 4 days of perineural ropivacaine attained all three discharge criteria in a median (25th–75th percentiles) of 25 (21–47) h, compared with 71 (46–89) h for those of the control group (estimated ratio, 0.47; 95% confidence interval, 0.32–0.67; P <0.001). Patients assigned to receive ropivacaine ambulated a median of 32 (17–47) m the afternoon after surgery, compared with 26 (13–35) m for those receiving normal saline (estimated ratio, 1.21; 95% confidence interval, 0.71–1.85; P = 0.42). Conclusions:Compared with an overnight cFNB, a 4-day ambulatory cFNB decreases the time to reach three important discharge criteria by an estimated 53% after tricompartment total knee arthroplasty. However, the extended infusion did not increase ambulation distance the afternoon after surgery. (ClinicalTrials.gov No. NCT00135889.)

A Multicenter, Randomized, Triple-Masked, Placebo-Controlled Trial of The Effect of Ambulatory Continuous Femoral Nerve Blocks on Discharge-Readiness Following Total Knee Arthroplasty In Patients on General Orthopaedic Wards

&NA; A continuous femoral nerve block (cFNB) involves the percutaneous insertion of a catheter adjacent to the femoral nerve, followed by a local anesthetic infusion, improving analgesia following total knee arthroplasty (TKA). Portable infusion pumps allow infusion continuation following hospital discharge, raising the possibility of decreasing hospitalization duration. We therefore used a multicenter, randomized, triple‐masked, placebo‐controlled study design to test the primary hypothesis that a 4‐day ambulatory cFNB decreases the time until each of three predefined readiness‐for‐discharge criteria (adequate analgesia, independence from intravenous opioids, and ambulation ≥30 m) are met following TKA compared with an overnight inpatient‐only cFNB. Preoperatively, all patients received a cFNB with perineural ropivacaine 0.2% from surgery until the following morning, at which time they were randomized to either continue perineural ropivacaine (n = 39) or switch to normal saline (n = 38). Patients were discharged with their cFNB and portable infusion pump as early as postoperative day 3. Patients who were given 4 days of perineural ropivacaine attained all three criteria in a median (25th–75th percentiles) of 47 (29–69) h, compared with 62 (45–79) h for those of the control group (Estimated ratio = 0.80, 95% confidence interval: 0.66–1.00; p = 0.028). Compared with controls, patients randomized to ropivacaine met the discharge criterion for analgesia in 20 (0–38) versus 38 (15–64) h (p = 0.009), and intravenous opioid independence in 21 (0–37) versus 33 (11–50) h (p = 0.061). We conclude that a 4‐day ambulatory cFNB decreases the time to reach three important discharge criteria by an estimated 20% following TKA compared with an overnight cFNB, primarily by improving analgesia.

Ambulatory Continuous Posterior Lumbar Plexus Nerve Blocks after Hip Arthroplasty : A Dual-center, Randomized, Triple-masked, Placebo-controlled Trial

Background:The authors tested the hypotheses that after hip arthroplasty, ambulation distance is increased and the time required to reach three specific readiness-for-discharge criteria is shorter with a 4-day ambulatory continuous lumbar plexus block (cLPB) than with an overnight cLPB. Methods:A cLPB consisting of 0.2% ropivacaine was provided from surgery until the following morning. Patients were then randomly assigned either to continue ropivacaine or to be switched to normal saline. Primary endpoints included (1) time to attain three discharge criteria (adequate analgesia, independence from intravenous analgesics, and ambulation ≥ 30 m) and (2) ambulatory distance in 6 min the afternoon after surgery. Patients were discharged with their cLPB and a portable infusion pump, and catheters were removed on the fourth postoperative day. Results:Patients given 4 days of perineural ropivacaine (n = 24) attained all three discharge criteria in a median (25th–75th percentiles) of 29 (24–45) h, compared with 51 (42–73) h for those of the control group (n = 23; estimated ratio = 0.62; 95% confidence interval, 0.45–0.92; P = 0.011). Patients assigned to receive ropivacaine ambulated a median of 34 (9–55) m the afternoon after surgery, compared with 20 (6–46) m for those receiving normal saline (estimated ratio = 1.3; 95% confidence interval, 0.6–3.0; P = 0.42). Three falls occurred in subjects receiving ropivacaine (13%), versus none in subjects receiving normal saline. Conclusions:Compared with an overnight cLPB, a 4-day ambulatory cLPB decreases the time to reach three predefined discharge criteria by an estimated 38% after hip arthroplasty. However, the extended infusion did not increase ambulation distance to a statistically significant degree.

The Effects of Local Anesthetic Concentration and Dose on Continuous Infraclavicular Nerve Blocks: A Multicenter, Randomized, Observer-Masked, Controlled Study

BACKGROUND: It remains unclear whether local anesthetic concentration or total drug dose is the primary determinant of continuous peripheral nerve block effects. The only previous investigation, involving continuous popliteal-sciatic nerve blocks, specifically addressing this issue reported that insensate limbs were far more common with higher volumes of relatively dilute ropivacaine compared with lower volumes of relatively concentrated ropivacaine. However, it remains unknown if this relationship is specific to the sciatic nerve in the popliteal fossa or whether it varies depending on anatomic location. We therefore tested the null hypothesis that providing ropivacaine at different concentrations and rates, but at an equal total basal dose, produces comparable effects when used in a continuous infraclavicular brachial plexus block. METHODS: Preoperatively, an infraclavicular catheter was inserted using the coracoid approach in patients undergoing moderately painful orthopedic surgery distal to the elbow. Patients were randomly assigned to receive a postoperative perineural ropivacaine infusion of either 0.2% (basal 8 mL/h, bolus 4 mL) or 0.4% (basal 4 mL/h, bolus 2 mL) through the second postoperative day. Both groups, therefore, received 16 mg of ropivacaine each hour with a possible addition of 8 mg every 30 min via a patient-controlled bolus dose. Our primary end point was the incidence of an insensate limb during the 24-h period beginning the morning after surgery. Secondary end points included analgesia and patient satisfaction. RESULTS: Patients given 0.4% ropivacaine (n = 27) experienced an insensate limb, a mean (sd) of 1.8 (1.6) times, compared with 0.6 (0.9) times for subjects receiving 0.2% ropivacaine (n = 23; estimated difference = 1.2 episodes, 95% confidence interval, 0.5–1.9 episodes; P = 0.001). Satisfaction with postoperative analgesia (scale 0–10, 10 = highest) was scored a median (25th–75th percentiles) of 10.0 (8.0–10.0) in Group 0.2% and 7.0 (5.3–8.9) in Group 0.4% (P = 0.018). Analgesia was similar in each group. CONCLUSIONS: For continuous infraclavicular nerve blocks, local anesthetic concentration and volume influence perineural infusion effects in addition to the total mass of local anesthetic administered. Insensate limbs were far more common with smaller volumes of relatively concentrated ropivacaine. This is the opposite of the relationship previously reported for continuous popliteal-sciatic nerve blocks. The interaction between local anesthetic concentration and volume is thus complex and varies among catheter locations.

Long-term pain, stiffness, and functional disability after total knee arthroplasty with and without an extended ambulatory continuous femoral nerve block: a prospective, 1-year follow-up of a multicenter, randomized, triple-masked, placebo-controlled trial.

Background: Previously, we have demonstrated that extending a continuous femoral nerve block (cFNB) from overnight to 4 days after total knee arthroplasty (TKA) provides clear benefits during the infusion, but not subsequent to catheter removal. However, there were major limitations in generalizing the results of that investigation, and we subsequently performed a very similar study using a multicenter format, with many health care providers, in patients on general orthopedic wards, thus greatly improving inference of the results to the general population. Not surprisingly, the perioperative/short-term outcomes differed greatly from the first, more limited study. We now present a prospective follow-up study of the previously published, multicenter, randomized controlled clinical trial to investigate the possibility that an extended ambulatory cFNB decreases long-term pain, stiffness, and functional disability after TKA, which greatly improves inference of the results to the general population. Methods: Subjects undergoing TKA received a cFNB with ropivacaine 0.2% from surgery until the following morning, at which time patients were randomized to continue either perineural ropivacaine (n = 28) or normal saline (n = 26). Patients were discharged with their catheter and a portable infusion pump, and catheters were removed on postoperative day 4. Health-related quality of life was measured using the Western Ontario and McMaster Universities Osteoarthritis Index preoperatively and then at 7 days, as well as 1, 2, 3, 6, and 12 months after surgery. This index evaluates pain, stiffness, and physical functional disability. For inclusion in the analysis, we required a minimum of 4 of the 6 time points, including day 7 and at least 2 of months 3, 6, and 12. Results: The 2 treatment groups had similar Western Ontario and McMaster Universities Osteoarthritis scores for the mean area-under-the-curve calculations (point estimate for the difference in mean area under the curve for the 2 groups [overnight infusion group − extended infusion group] = 3.8; 95% confidence interval, −3.8 to +11.3; P = 0.32) and at all individual time points (P > 0.05). Conclusions: This investigation found no evidence that extending an overnight cFNB to 4 days improves (or worsens) subsequent pain, stiffness, or physical function after TKA in patients of multiple centers convalescing on general orthopedic wards.

Health-related quality of life after tricompartment knee arthroplasty with and without an extended-duration continuous femoral nerve block: A prospective, 1-year follow-up of a randomized, triple-masked, placebo-controlled study

BACKGROUND: We previously provided evidence that extending an overnight continuous femoral nerve block to 4 days after tricompartment knee arthroplasty (TKA) provides clear benefits during the perineural infusion in the immediate postoperative period. However, it remains unknown if the extended infusion improves subsequent health-related quality of life between 7 days and 12 mo. METHODS: Patients undergoing TKA received a femoral perineural infusion of ropivacaine 0.2% from surgery until the following morning, at which time patients were randomized to either continue perineural ropivacaine (n = 25) or normal saline (n = 25) in a double-masked fashion. Patients were discharged with their catheter and a portable infusion pump, and catheters were removed on postoperative day 4. Health-related quality of life was measured using the Western Ontario and McMaster Universities Osteoarthritis (WOMAC) Index preoperatively and then at 7 days, as well as 1, 2, 3, 6, and 12 mo after surgery. The WOMAC evaluates three dimensions of health-related quality of life: pain, stiffness, and physical functional disability. For inclusion in the analysis, we required a minimum of 4 of the 6 time points, including day 7 and at least 2 of mo 3, 6, and 12. RESULTS: The two treatment groups had similar WOMAC scores for the mean area under the curve calculations (point estimate for the difference in mean area under the curve for the two groups [overnight infusion group−extended infusion group] = 1.2, 95% confidence interval: −5.6 to +8.0; P = 0.72) and at all individual time points (P > 0.05). CONCLUSIONS: We found no evidence that extending an overnight continuous femoral nerve block to 4 days improves (or worsens) subsequent health-related quality of life between 7 days and 12 mo after TKA. (ClinicalTrials.gov number, NCT00135889.)

Health-Related Quality of Life After Hip Arthroplasty With and Without an Extended-Duration Continuous Posterior Lumbar Plexus Nerve Block: A Prospective, 1-Year Follow-Up of a Randomized, Triple-Masked, Placebo-Controlled Study

BACKGROUND: We previously reported that extending an overnight continuous posterior lumbar plexus nerve block to 4 days after hip arthroplasty provides clear benefits during the perineural infusion in the immediate postoperative period. However, it remains unknown whether the extended infusion improves subsequent health-related quality of life. METHODS: Patients undergoing hip arthroplasty received a posterior lumbar plexus perineural infusion of ropivacaine 0.2% from surgery until the following morning, at which time patients were randomized to continue either perineural ropivacaine (n = 24) or normal saline (n = 23) in a double-masked fashion. Patients were discharged with their catheter and a portable infusion pump, and catheters were removed on postoperative Day 4. Health-related quality of life was measured using the Western Ontario and McMaster Universities Osteoarthritis (WOMAC) Index preoperatively and then at 7 days and 1, 2, 3, 6, and 12 mo after surgery. The WOMAC evaluates three dimensions of health-related quality of life, such as pain, stiffness, and physical functional disability (global score of 0–96, lower scores indicate lower levels of symptoms or physical disability). For inclusion in the primary analysis, we required a minimum of three of the six timepoints, including Day 7 and at least two of Months 3, 6, and 12. RESULTS: The two treatment groups had similar global WOMAC scores for the mean area under the curve calculations (point estimate for the difference in mean area under the curve for the two groups [extended infusion group—overnight infusion group] = 0.8, 95% confidence interval: −5.3 to + 6.8 [−5.5% to + 7.1%]; P = 0.80) and at all individual timepoints (P > 0.05). CONCLUSIONS: This investigation found no evidence that extending an overnight continuous posterior lumbar plexus nerve block to 4 days improves (or worsens) subsequent health-related quality of life between 7 days and 12 mo after hip arthroplasty.