Pia Jæger

Adductor canal block versus femoral nerve block for analgesia after total knee arthroplasty: a randomized, double-blind study.

Background and Objectives Femoral nerve block (FNB), a commonly used postoperative pain treatment after total knee arthroplasty (TKA), reduces quadriceps muscle strength essential for mobilization. In contrast, adductor canal block (ACB) is predominately a sensory nerve block. We hypothesized that ACB preserves quadriceps muscle strength as compared with FNB (primary end point) in patients after TKA. Secondary end points were effects on morphine consumption, pain, adductor muscle strength, morphine-related complications, and mobilization ability. Methods We performed a double-blind, randomized, controlled study of patients scheduled for TKA with spinal anesthesia. The patients were randomized to receive either a continuous ACB or an FNB via a catheter (30-mL 0.5% ropivacaine given initially, followed by a continuous infusion of 0.2% ropivacaine, 8 mL/h for 24 hours). Muscle strength was assessed with a handheld dynamometer, and we used the percentile change from baseline for comparisons. The trial was registered at clinicaltrials.gov (Identifier: NCT01470391). Results We enrolled 54 patients, of which 48 were analyzed. Quadriceps strength as a percentage of baseline was significantly higher in the ACB group compared with the FNB group: (median [range]) 52% [31–71] versus 18% [4–48], (95% confidence interval, 8–41; P = 0.004). There was no difference between the groups regarding morphine consumption (P = 0.94), pain at rest (P = 0.21), pain during flexion of the knee (P = 0.16), or adductor muscle strength (P = 0.39); neither was there a difference in morphine-related adverse effects or mobilization ability (P > 0.05). Conclusions Adductor canal block preserved quadriceps muscle strength better than FNB, without a significant difference in postoperative pain.

Effects of Adductor-Canal-Blockade on pain and ambulation after total knee arthroplasty: a randomized study

Total knee arthroplasty (TKA) is associated with intense post‐operative pain. Besides providing optimal analgesia, reduction in side effects and enhanced mobilization are important in this elderly population. The adductor‐canal‐blockade is theoretically an almost pure sensory blockade. We hypothesized that the adductor‐canal‐blockade may reduce morphine consumption (primary endpoint), improve pain relief, enhance early ambulation ability, and reduce side effects (secondary endpoints) after TKA compared with placebo.

Adductor canal block versus femoral nerve block and quadriceps strength: a randomized, double-blind, placebo-controlled, crossover study in healthy volunteers.

Background:The authors hypothesized that the adductor canal block (ACB), a predominant sensory blockade, reduces quadriceps strength compared with placebo (primary endpoint, area under the curve, 0.5–6 h), but less than the femoral nerve block (FNB; secondary endpoint). Other secondary endpoints were adductor strength and ability to ambulate. Methods:The authors enrolled healthy young men into this double blind, placebo-controlled, randomized, crossover study. On two separate study days, subjects received either ACB or FNB with ropivacaine, and placebo in the opposite limb. Strength was assessed as maximum voluntary isometric contraction for quadriceps and adductor muscles. In addition, subjects performed three standardized ambulation tests. Clinicaltrials.gov Identifier: NCT01449097. Results:Twelve subjects were randomized, 11 analyzed. Quadriceps strength (area under the curve, 0.5–6 h) was significantly reduced when comparing ACB with placebo (5.0 ± 1.0 vs. 5.9 ± 0.6, P = 0.02, CI: −1.5 to −0.2), FNB with placebo (P = 0.0004), and when comparing FNB with ACB (P = 0.002). The mean reduction from baseline was 8% with ACB and 49% with FNB. The only statistically significant difference in adductor strength was between placebo and FNB (P = 0.007). Performance in all mobilization tests was reduced after an FNB compared with an ACB (P < 0.05). Conclusions:As compared with placebo ACB statistically significantly reduced quadriceps strength, but the reduction was only 8% from baseline. ACB preserved quadriceps strength and ability to ambulate better than FNB did. Future studies are needed to compare the analgesic effect of the ACB with the FNB in a clinical setting.

Continuous adductor-canal-blockade for adjuvant post-operative analgesia after major knee surgery: preliminary results.

Because both the saphenous nerve and in part the obturator nerve are traversing the adductor canal of the thigh, we hypothesised that repeated administration of a local anaesthetic (LA) into this aponeurotic space could be a useful option for post‐operative analgesia after knee replacement surgery. A systematic search of the literature pertinent to the blockade of the saphenous and/or obturator nerves for pain relief after knee surgery was conducted. Further, pain and opioid requirements were evaluated in eight patients receiving a continuous blockade of the saphenous and obturator nerve (adductor‐canal‐blockade) after total knee arthroplasty (TKA). Finally, we performed cross‐sectional MR scans of the adductor canal after injection of ropivacaine 30 ml in one patient. The systematic literature search revealed only one controlled study, where selective blockade of the saphenous nerve was investigated for the purpose of clinical pain relief after knee arthroscopy. We located no studies reporting on saphenous and/or obturator nerve block for pain relief after TKA. Preliminary findings in eight patients demonstrated that a continuous adductor‐canal‐blockade for 48 h after TKA was associated with low mean pain scores at rest and low mean requirements for supplemental morphine. MR scans in one patient demonstrated that 30 ml of LA filled the adductor canal, including the distal part, where the posterior branch of the obturator nerve joins the vessels and the saphenous nerve. Continuous adductor‐canal‐blockade may be a valuable adjunct for post‐operative analgesia after major knee surgery. These preliminary results should be confirmed in randomised, controlled trials.

Effect of adductor-canal-blockade on established, severe post-operative pain after total knee arthroplasty: a randomised study.

In this proof‐of‐concept study, we investigated the effect of the predominantly sensory adductor‐canal‐blockade on established pain in the early post‐operative period after total knee arthroplasty (TKA). We hypothesised that the adductor‐canal‐blockade would reduce pain during flexion of the knee (primary end point) and at rest, as well as reducing morphine consumption and morphine‐related side effects (secondary outcomes) compared with placebo.

Effect of adductor canal block versus femoral nerve block on quadriceps strength, mobilization, and pain after total knee arthroplasty: a randomized, blinded study.

Background and Objectives Total knee arthroplasty (TKA) is often associated with severe pain. Different regional anesthetic techniques exist, all with varying degrees of motor blockade. We hypothesized that pain relief provided by the adductor canal block (ACB) could increase functional muscle strength. Methods We included 50 TKA patients with severe movement-related pain; defined as having visual analog scale pain score of greater than 60 mm during active flexion of the knee. The ACB group received an ACB with ropivacaine 0.2% 30 mL and a femoral nerve block (FNB) with 30 mL saline. The FNB group received an ACB with 30 mL saline and an FNB with ropivacaine 0.2% 30 mL. We compared the effect of the ACB versus FNB on maximum voluntary isometric contraction of the quadriceps muscle relative to a postoperative baseline value. Secondary end points were differences between groups in ability to ambulate and changes in pain scores (Clinicaltrials.gov identifier NCT01922596). Results After block, the quadriceps maximum voluntary isometric contraction increased to 193% (95% confidence interval [CI], 143–288) of the baseline value in the ACB group and decreased to 16% (95% CI, 3–33) in the FNB group with an estimated difference of 178% (95% CI, 136–226), P < 0.0001. Pain scores were similar between groups. Before block, 2 of 25 patients in each group were unable to perform the Timed-Up-and-Go test; after block, this number increased to 7 of 25 in the FNB group and decreased to 0 of 25 in the ACB group. Conclusion Adductor canal block provides a clinically relevant and statistically significant increase in quadriceps muscle strength for patients in severe pain after TKA.

Prevalence of saphenous nerve injury after adductor-canal-blockade in patients receiving total knee arthroplasty.

Adductor‐canal‐blockade is a new technique for pain relief after knee surgery. This block could cause nerve injury and the aim of this follow‐up study was to determine the prevalence of saphenous nerve injury in patients receiving adductor‐canal‐blockade for pain treatment after total knee arthroplasty.

Adductor Canal Block for Postoperative Pain Treatment after Revision Knee Arthroplasty: A Blinded, Randomized, Placebo-Controlled Study

Background Revision knee arthroplasty is assumed to be even more painful than primary knee arthroplasty and predominantly performed in chronic pain patients, which challenges postoperative pain treatment. We hypothesized that the adductor canal block, effective for pain relief after primary total knee arthroplasty, may reduce pain during knee flexion (primary endpoint: at 4 h) compared with placebo after revision total knee arthroplasty. Secondary endpoints were pain at rest, morphine consumption and morphine-related side effects. Methods We included patients scheduled for revision knee arthroplasty in general anesthesia into this blinded, placebo-controlled, randomized trial. Patients were allocated to an adductor canal block via a catheter with either ropivacaine or placebo; bolus of 0.75% ropivacaine/saline, followed by infusion of 0.2% ropivacaine/saline. Clinicaltrials.gov ID: NCT01191593. Results We enrolled 36 patients, of which 30 were analyzed. Mean pain scores during knee flexion at 4 h (primary endpoint) were: 52±22 versus 71±25 mm (mean difference 19, 95% CI: 1 to 37, P = 0.04), ropivacaine and placebo group respectively. When calculated as area under the curve (1–8 h/7 h) pain scores were 55±21 versus 69±21 mm during knee flexion (P = 0.11) and 39±18 versus 45±23 mm at rest (P = 0.43), ropivacaine and placebo group respectively. Groups were similar regarding morphine consumption and morphine-related side effects (P>0.05). Conclusions The only statistically significant difference found between groups was in the primary endpoint: pain during knee flexion at 4 h. However, due to a larger than anticipated dropout rate and heterogeneous study population, the study was underpowered. Trial Registration Clinicaltrials.gov NCT01191593

Adductor canal blockade for moderate to severe pain after arthroscopic knee surgery: a randomized controlled trial.

The analgesic effect of the adductor canal block (ACB) after knee surgery has been evaluated in a number of trials. We hypothesized that the ACB would provide substantial pain relief to patients responding with moderate to severe pain after arthroscopic knee surgery.

The Effect of Local Anesthetic Volume Within the Adductor Canal on Quadriceps Femoris Function Evaluated by Electromyography: A Randomized, Observer- and Subject-Blinded, Placebo-Controlled Study in Volunteers.

BACKGROUND:Single-injection adductor canal block (ACB) provides analgesia after knee surgery. Which nerves that are blocked by an ACB and what influence—if any—local anesthetic volume has on the effects remain undetermined. We hypothesized that effects on the nerve to the vastus medialis muscle (which besides being a motor nerve innervates portions of the knee) are volume-dependent. METHODS:In this assessor- and subject-blinded randomized trial, 20 volunteers were included. On 3 separate days, subjects received an ACB with different volumes (10, 20, and 30 mL) of lidocaine 1%. In addition, they received a femoral nerve block and a placebo ACB. The effect on the vastus medialis (primary endpoint) and the vastus lateralis was evaluated using noninvasive electromyography (EMG). Quadriceps femoris muscle strength was evaluated using a dynamometer. RESULTS:There was a statistically significant difference in EMG response from the vastus medialis, dependent on volume. Thirty-five percent (95% confidence interval [CI], 18–57) of the subjects had an affected vastus medialis after an ACB with 10 mL compared with 84% (95% CI, 62–94) following 20 mL (P = 0.03) and 100% (95% CI, 84–100) when 30 mL was used (P = 0.0001). No statistically significant differences were found between volume and effect on the vastus lateralis (P = 0.81) or in muscle strength (P = 0.15). CONCLUSIONS:For ACB, there is a positive correlation between local anesthetic volume and effect on the vastus medialis muscle. Despite the rather large differences in EMG recordings, there were no statistically significant differences in quadriceps femoris muscle strength. Subsequent clinical studies comparing different volumes in a surgical setting, powered to show differences not only in analgesic efficacy, but also in adverse events, are required.