An Obturator Nerve Block does not Alleviate Postoperative Pain after Total Hip Arthroplasty: a Randomized Clinical Trial

Subpectineal obturator nerve block reduces opioid consumption after hip arthroscopy: a triple-blind, randomized, placebo-controlled trial

BACKGROUND

Hip arthroscopy causes severe pain during the first few hours in the postoperative care unit. This is probably due to the intraoperative stretching of the hip joint capsule. Pain relief requires high doses of opioids which may prolong recovery and may cause opioid-related adverse events.The majority of hip joint capsule nociceptors are located anteriorly. The obturator nerve innervates the anteromedial part of the hip joint capsule. We hypothesized that a subpectineal obturator nerve block using 15 ml bupivacaine 5 mg/mL with added epinephrine 5 μg/mL would reduce the opioid consumption after hip arthroscopy.

METHODS

40 ambulatory hip arthroscopy patients were enrolled in this randomized, triple-blind controlled trial. All patients were allocated to a preoperative active or placebo subpectineal obturator nerve block. The primary outcome was opioid consumption for the first 3 hours in the postanesthesia care unit. Secondary outcomes were pain, nausea, and hip adductor strength.

RESULTS

34 patients were analyzed for the primary outcome. The mean intravenous morphine equivalent consumption in the subpectineal obturator nerve block group was 11.9 mg vs 19.7 mg in the placebo group (p<0.001). The hip adductor strength was significantly reduced in the active group. No other intergroup differences were observed regarding the secondary outcomes.

CONCLUSION

We found a significant reduction in the opioid consumption for patients receiving an active subpectineal obturator nerve block. The postoperative intravenous morphine equivalent reduction the first painful 3 hours was reduced by 40% for patients receiving a subpectineal obturator nerve block in this randomized, triple-blind trial.

TRIAL REGISTRATION NUMBER

EudraCT database 2021-006575-42.

A randomized controlled trial of iliopsoas plane block vs. femoral nerve block for hip arthroplasty

BACKGROUND

Iliopsoas plane block (IPB) is a novel analgesic technique for hip surgery that retains quadriceps strength. However, evidence from randomized controlled trial is remains unavailable. We hypothesized that IPB, as a motor-sparing analgesic technique, could match the femoral nerve block (FNB) in pain management and morphine consumption, providing an advantage for earlier functional training in patients underwent hip arthroplasty.

METHODS

We recruited ninety patients with femoral neck fracture, femoral head necrosis or hip osteoarthritis who were scheduled for unilateral primary hip arthroplasty were recruited and received either IPB or FNB. Primary outcome was the pain score during hip flexion at 4 h after surgery. Secondary outcomes included quadriceps strength and pain scores upon arrival at post anesthesia care unit (PACU) and at 2, 4, 6, 24, 48 h after surgery, the first time out of bed, total opioids consumption, patient satisfaction, and complications.

RESULTS

There was no significant difference in terms of pain score during hip flexion at 4 h after surgery between the IPB group and FNB group. The quadriceps strength of patients receiving IPB was superior to those receiving FNB upon arrival at PACU and at 2, 4, 6 and 24 h after surgery. The IPB group showed a shorter first time out of bed compared to the FNB group. However, there were no significant differences in terms of pain scores within 48 h after surgery, total opioids consumption, patient satisfaction and complications between the two groups.

CONCLUSION

IPB was not superior to FNB in terms of postoperative analgesia for hip arthroplasty. However, IPB could serve as an effective motor-sparing analgesic technique for hip arthroplasty, which would facilitate early recovery and rehabilitation. This makes IPB worth considering as an alternative to FNB.

TRIAL REGISTRATION

The trial was registered prior to patient enrollment at the Chinese Clinical Trial Registry (ChiCTR2200055493; registration date: January 10, 2022; enrollment date: January 18, 2022; https://www.chictr.org.cn/searchprojEN.html ).

Analgesic effect of iliopsoas plane block for hip fracture

Background

Hip fracture and surgery are associated with moderate to severe pain, which hampers early mobilization and extends the hospital stay. Femoral nerve block and fascia iliaca compartment block could provide effective postoperative pain relief. Unfortunately, they could weaken the strength of the quadriceps muscle and increase the risk of falls. Iliopsoas plane block (IPB) is a novel motor-sparing regional technique, which targets the sensory branches of the hip joint originating from the femoral nerve. However, the analgesic effect of IPB has not been confirmed yet.

Case presentation

In the present case series, IPB and lateral femoral cutaneous nerve block were implemented under the guidance of ultrasound for eight patients with hip fractures. The median (IQR) visual analog scale (VAS) score (0–10; 0: no pain, 10: worst pain) decreased from 1.5 (0.25–2) before IPB to 0 (0–0) 0.5h after IPB at rest. The median (IQR) VAS score decreased from 8 (7–8) before IPB to 2 (1–2) 0.5h after IPB during flexion of hip 30°. Pain score was no more than one at rest and three during flexion of the hip 30° within 48h after surgery. Furthermore, the MMT grades of quadriceps strength were no less than four after IPB.

Conclusions

Our case series firstly highlights that IPB might be an effective analgesic technique for hip fracture and surgery, while retaining motor function.

Ultrasound-guided supra-inguinal fascia Iliaca compartment block for older adults admitted to the emergency department with hip fracture: a randomized controlled, double-blind clinical trial

Background

Hip fracture is common in older adults, and can cause severe post-fracture pain. Fascia iliaca nerve block has consequently been used for preoperative analgesia.

Methods

We performed a randomized, controlled, double-blind clinical trial and recruited older patients with hip fractures. These patients were randomized into two groups and received ultrasound-guided fascia iliaca compartment block using either the supra-inguinal approach (group F) or the classical approach (group C). Heart rate, blood pressure, and resting and exercising visual analog scales were recorded before the procedure and at 30 min, and 6, 12, and 24 h after completion of the procedure. We recorded the duration of the procedure—as well as complications such as bleeding, hypotension, and intractable vomiting; the sleep duration in a 24 h period was also documented.

Results

A total of 38 patients completed the trial, and we observed no differences in the baseline characteristics or pre-procedural measurements between the two groups. Compared with the patients in group C, patients in group F exhibited significantly lower exercising VAS scores at 6 and 12 h after the procedure, faster heart rates at 6 and 24 h after the procedure, a longer procedural duration, and a longer sleep duration. There were no differences in the frequencies of complications between the two groups. The percentages of patients who took oral analgesics and the numbers of medications consumed were also not different between the two groups.

Conclusions

The supra-inguinal FICB provided effective analgesia and improved exercise tolerance compared with the classical approach.

Trial registration

The trial was registered at the Chinese Clinical Trial Registry (registration number: ChiCTR2100045644, registration date: 2021 April 20).

Obturator nerve block does not provide analgesic benefits in total hip arthroplasty under multimodal analgesic regimen: a randomized controlled trial

BACKGROUND AND OBJECTIVES

Although regional analgesia is considered an important component of optimal pain management, use of peripheral nerve blocks for total hip arthroplasty remains controversial. Since the obturator nerve innervates the anteromedial part of the joint capsule, we hypothesized that an obturator nerve block would decrease the opioid consumption after total hip arthroplasty.

METHODS

In this single center, prospective, triple blinded study, we randomly allocated 60 patients undergoing total hip arthroplasty under opioid-sparing total intravenous general anesthesia to a preoperative obturator nerve block or a sham block (placebo group) using 20 mL of ropivacaine 0.2% or saline, respectively. All patients received a multimodal analgesic regimen with non-opioid analgesics including periarticular local infiltration analgesia. The primary outcome was the intravenous opioid consumption in the post-anesthesia care unit.

RESULTS

Median (IQR) intravenous oxycodone consumption in the post-anesthesia care unit was 4 (2, 7.5) mg in the obturator nerve block group and 3 (0, 4) mg in the placebo group (p=0.05). There were no differences in pain scores between groups in the first 24 hours except at arrival on the surgical ward with significant higher pain scores in the placebo group (p=0.03). The ability to stand up and walk within 24 hours was comparable between groups as was the time to first walk (180 (90, 720) vs 240 (120, 780) min for the obturator nerve block and placebo groups, respectively; p=0.62).

CONCLUSIONS

Obturator nerve block did not improve postoperative opioid consumption after total hip arthroplasty performed under general anesthesia with a multimodal analgesic regimen.

TRIAL REGISTRATION NUMBER

NCT04085640.

Minimum effective volume of ropivacaine for ultrasound-guided supra-inguinal fascia iliaca compartment block

Supra inguinal fascia iliaca compartment block (FICB) is increasingly used in elderly patients with hip fractures. However, the minimum effective volume of local anesthetics required for ultrasound-guided supra-inguinal FICB has not been determined. With ethical committee approval and written informed consent from patients, we studied 21 consecutive patients of ASA physical status I–III undergoing surgery for hip fracture who met the inclusion criteria. Blocks were performed before going to the operation room. We determined the injection volumes of 0.25% ropivacaine for consecutive patients from the preceding patient's outcome. The initial volume was 30 ml. The testing interval was set at 10 ml, and the lowest volume was 5 ml. An effective block was defined as loss of sensation of pinprick in the territory of the femoral nerve and lateral cutaneous nerve of the thigh 30 min after the injection. The aim of this study was to determine the 50% effective volume (EV₅₀) and the 95% effective volume (EV₉₅) of 0.25% ropivacaine for ultrasound-guided supra-inguinal FICB using Logistic regression analysis. EV₅₀ and EV₉₅ of 0.25% ropivacaine for ultrasound-guided supra-inguinal FICB calculated with logistic regression analysis were 15.01 ml (95% confidence interval, 6.53–22.99 ml) and 26.99 ml (95% confidence interval, 20.54–84.09 ml), respectively. EV₅₀ and EV₉₅ of 0.25% ropivacaine for ultrasound-guided supra-inguinal FICB were 15.01 ml and 26.99 ml, respectively.

Clinical trial number: UMIN000027277 (URL https://www.umin.ac.jp/ctr/index-j.htm).

Peripheral nerve blocks for analgesia after elective total hip arthroplasty

A significant subgroup of patients suffer from moderate or severe pain after total hip arthroplasty (THA). Regional analgesia has the potential to reduce post-operative pain and thereby spare patients from opioids, but regional analgesia of the hip is complicated as the area is innervated by multiple nerves. However, the nociceptors of the hip joint are primarily innervated by the obturator and femoral nerves. The effect of an obturator nerve block (ONB) on pain following THA has never been investigated. A femoral nerve block is known to reduce pain after THA, but is unfortunately accompanied by an increased risk of fall. We have developed a novel nerve block-the iliopsoas plane block (IPB)-that has the potential to anaesthetize the hip articular sensory branches of the femoral nerve without causing motor blockade.