Seattle, Washington 98104


Hip arthroscopy is commonly associated with moderate-to-severe postoperative pain. The purpose of this study is to investigate the analgesic efficacy of preoperative obturator nerve block as measured by postoperative pain scores and postoperative analgesic requirements. The primary outcome will be the patient's first reported pain scores in the post anesthesia care unit (PACU).

Study summary:

RESEARCH DESIGN AND METHODS Patient selection The proposed study will be a prospective randomized placebo-controlled trial. Eligibility criteria will include patients having primary unilateral ambulatory hip arthroscopy for femoral acetabular impingement, age 18 to 65 years, ASA physical status I to III, and ability to follow the protocol. Exclusion criteria: patient refusal, inability to comprehend the consent form, age < 18, and > 65 years of age; contraindications to obturator nerve blockade (pre-existing neuromuscular or peripheral nerve disorder, localized infection, or bleeding disorder); allergy to opioids or local anesthetics; allergy to celecoxib or sulfa medications or nonsteroidal anti-inflammatory medications (NSAIDs); chronic opioid use (> 1 month of 60 mg morphine PO equivalents daily); and, women who are pregnant or breastfeeding. Consent Patients will be enrolled preoperatively in either the orthopedic surgery clinic or through the anesthesia preoperative clinic after the hip arthroscopy surgery is scheduled Randomization, Blinding, and Allocation Study medications will be administered by the primary investigator who will perform or closely supervise all ultrasound-guided obturator nerve blocks. Randomization will be performed with use of computerized random number generator and then each assignment will be placed into an opaque sealed envelope. Upon enrollment into the study and consent obtained, the next sealed envelope (numbered sequentially) will be opened and the patient allocated to either: - Group 1 (Treatment), Ultrasound-guided obturator nerve block: 20 ml ropivacaine 0.5% - Group 2 (Placebo), Ultrasound-guided saline placebo block: 5 mL sterile saline 0.9% The primary investigator will not be involved in any subsequent postoperative data collection. The sub-investigators will perform all subsequent data collection and will be blinded to group allocation. Intervention Following randomization, the principle investigator will perform the block procedure 30 minutes prior to expected transfer back to the operating room. Anesthetic care All intraoperative anesthetic care will be standardized as well, including general endotracheal anesthesia induction using propofol 1.5-2mg/kg IV, succinylcholine 1-1.5mg/kg IV or rocuronium 0.6-1mg/kg IV (based on the clinical discretion of the blinded anesthesia provider). In order to provide adequate intraoperative analgesia for both groups for the expected duration of the procedure, 1 mg of intravenous hydromorphone will be administered 10 minutes prior to surgical incision. No further intraoperative opioids will be administered. Neuromuscular blockade will be maintained with rocuronium as indicated by surgical requirements and titrated by neuromuscular monitoring, and reversed in standard fashion prior to emergence from general anesthesia. At the end of the procedure, the surgeon will inject ropivacaine 0.25% 30 mL in each of the 2 arthroscopic portal sites for a total of 60 ml ropivacaine 0.25% in all subjects as is standard practice for all hip arthroscopy patients. Subjects will be given a log to record their postoperative pain scores and oxycodone consumption for the 1st 24 hours after discharge. Outcomes The primary outcome will be the pain immediately upon arrival to the post anesthesia care unit. This will be measured by an 11-point numerical rating scale (NRS 0 = no pain, and 10 = worst pain imaginable). Secondary outcomes will include NRS pain scores at additional time frames for pain score self-assessments will include: 1. 3-4 hours after arriving home 2. Within 1 hour prior to going to sleep 3. Within 1 hour after waking up the following day. 4. 24 hours after surgery Additional secondary outcomes will also include: cumulative 24-hour postoperative opioid consumption, percentage of patients with postoperative nausea and vomiting, sleep disturbance (difficulty going to sleep or waking up from sleep due to postoperative pain). Expected Time Frame Typically, 4-5 hip arthroscopies per week are performed. Thus the expected timetable for recruitment will take at least 6-12 months


Inclusion Criteria: - Primary unilateral ambulatory hip arthroscopy - Age 18 to 65 years - ASA physical status I to III - Ability to follow the protocol. Exclusion Criteria: - Age <18 or >65 years of age - Contraindications to peripheral nerve blockade - Allergy to opioids or local anesthetics - Allergy to sulfa medications or nonsteroidal anti-inflammatory medications - Chronic opioid - Patient refusal

Study is Available At:

Original ID:




Secondary ID:

Study Acronym:

Brief Title:

Ultrasound-Guided Obturator Nerve Block for Ambulatory Hip Arthroscopy

Official Title:

Ultrasound-Guided Obturator Nerve Block for Ambulatory Hip Arthroscopy: A Prospective, Randomized Controlled Trial

Overall Status:


Study Phase:




Minimum Age:

18 Years

Maximum Age:

65 Years

Quick Facts

Healthy Volunteers
Oversight Has DMC
Study Is FDA Regulated
Study Is Section 801
Has Expanded Access

Study Source:

Benaroya Research Institute

Oversight Authority:

United States: Institutional Review Board

Reasons Why Stopped:

Study Type:


Study Design:

Allocation: Randomized, Endpoint Classification: E

Number of Arms:


Number of Groups:


Total Enrollment:


Enrollment Type:


Overall Contact Information

Official Name:Francis Salinas, MD
Principal Investigator
Virginia Mason Medical Center
Primary Contact:Francis Salinas, MD
Backup Contact:Stan Yuan, MD

Study Dates

Start Date:May 2014
Completion Date:September 2015
Completion Type:Anticipated
Primary Completion Date:September 2015
Primary Completion Type:Anticipated
Verification Date:January 2015
Last Changed Date:January 26, 2015
First Received Date:November 20, 2014

Study Outcomes

Outcome Type:Secondary Outcome
Measure:Pain scores for the 1st 24 hours after surgery (Numeric Rating Scale Pain)
Time Frame:1st 24 hours after completion of surgery.
Safety Issues:False
Description:Numeric Rating Scale Pain prior to hospital discharge, 1 hour after arriving home, 4 hours after arriving home, 1 hour prior to going to sleep, 1 hour after waking up the next morning, 24 hours after surgery
Outcome Type:Secondary Outcome
Measure:Opioid (analgesic) consumption
Time Frame:From the start of surgery to 24 hours after surgery complete (average surgical duration 2.5 hours).
Safety Issues:False
Description:Cumulative 24-hr postoperative opioid consumption
Outcome Type:Secondary Outcome
Measure:Sleep quality on on the day of surgery (Did subjects have difficulty going to sleep or wake up from sleep due to pain?)
Time Frame:Within 12-24 hours after discharge to home (from the hospital); typically the same night of the day
Safety Issues:False
Description:Did subjects have difficulty going to sleep or wake up from sleep due to pain?
Outcome Type:Secondary Outcome
Measure:Nausea (Number of episodes of nausea and vomiting during the 1st 24 hours postoperatively)
Time Frame:1st 24 hours after surgery
Safety Issues:False
Description:Number of episodes of nausea and vomiting during the 1st 24 hours postoperatively
Outcome Type:Secondary Outcome
Measure:Post anesthesia care unit discharge (Time required to meet discharge criteria from phase 2 PACU)
Time Frame:Wihtin 6 hours from end of surgery.
Safety Issues:False
Description:Time required to meet discharge criteria from phase 2 PACU, able to be discharged home
Outcome Type:Primary Outcome
Measure:Immediate pain score upon arrival to phase 1 PACU (NRS pain score)
Time Frame:Within 5-30 minutes upon leaving operating room and arrival to Phase I recovery
Safety Issues:False
Description:Initial NRS pain score upon arrival in the post anesthesia cafe unit (PACU)

Study Interventions

Intervention Type:Procedure
Name:Obturator Nerve Block
Description:Ultrasound-guided obturator nerve block with 20 mL of treatment drug (Ropivacaine 0.5% [local anesthetic]) 30 minutes prior to induction of anesthesia.
Arm Name:Obturator nerve block
Other Name:Nerve block
Intervention Type:Drug
Arm Name:Obturator nerve block
Intervention Type:Drug
Name:Placebo Saline
Arm Name:Sham block

Study Arms

Study Arm Type:Placebo Comparator
Arm Name:Sham block
Description:Placebo arm. Ultrasound-guided injection of 3-5 mL normal saline in the subcutaneous tissue in the same location as would for an obturator nerve block.
Study Arm Type:Active Comparator
Arm Name:Obturator nerve block
Description:Ultrasound-guided single-injection obturator nerve block with 20 mL ropivacaine 0.5%

Study Agencies

Agency Class:Other
Agency Type:Lead Sponsor
Agency Name:Benaroya Research Institute

Sample and Retention Information

There are no available Sample and Retention Information

Study References

There are no available Study References

Data Source:

Date Processed: January 21, 2020

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