PENG Block Versus LP Block for THA Postop Pain

The purpose of this randomized, double blinded, prospective study is to compare the postoperative analgesia provided by the PENG block to that provided by the LPB for patients undergoing primary anterior approach THA.

Regional anesthesia procedures represent a common modality for postoperative analgesia after total hip arthroplasty surgeries (THA). The standard practice many years has been the Lumbar Plexus block (LPB), which anesthetizes the L1-L5 lumbar nerve roots1. While the LPB offers analgesia from the associated sensory block, it also blocks motor fibers, leading to lower extremity weakness that could potentially delay the patient's ability to participate in early physical therapy and may thereby delay discharge. In the past several years, newer regional anesthesia block approaches have been described and investigated in an attempt to provide patients with postoperative analgesia while avoiding associated muscle weakness, facilitating earlier physical therapy participation and discharge. One such nerve block is the peri-capsular nerve group (PENG) block, which anesthetizes the articular branches of the femoral, obturator, and accessory obturator nerves providing sensory innervation to the hip joint capsule without consistently causing lower extremity weakness2. Some institutions are utilizing the PENG block to provide postoperative analgesia and facilitate early mobilization. There are currently no prospective studies that directly compare the efficacy of LPB to PENG block for providing postoperative analgesia after THA.

Those subjects assigned to the PENG treatment arm will receive a PENG block using 20mL of 0.2% ropivacaine with 1:400,000 epinephrine dosed in 5mL increments with negative aspiration beforehand and between each aliquot.

Those subjects assigned to the LPB treatment arm will receive a stimulation-based LPB dosed with 20cc of 0.2% ropivacaine with 1:400,000 dilution epinephrine dosed in 5mL increments with negative aspiration beforehand and between each aliquot.

a comparison of patient-reported numeric rating scale (NRS) pain scores with movement at six hours following block placement. Equivalency will be defined as a difference of less than one point in either direction on the eleven-point NRS pain scale. Score ranges from 0-10 with a higher score denoting more pain.

a comparison of patient-reported numeric rating scale (NRS) pain scores with movement at 12 hours following block placement. Score ranges from 0-10 with a higher score denoting more pain.

a comparison of patient-reported numeric rating scale (NRS) pain scores with movement at 18 hours following block placement. Score ranges from 0-10 with a higher score denoting more pain.

a comparison of patient-reported numeric rating scale (NRS) pain scores with movement at 24 hours following block placement. Score ranges from 0-10 with a higher score denoting more pain.

straight leg raise at 6 hours after block placed rated on a 0-5 scale with a higher score indicating better movement

Inclusion Criteria: elective primary total hip arthroplasty surgery anterior approach provided informed consent no contraindications to medications used in providing the analgesic blocks Exclusion Criteria: contraindications to regional anesthesia, such as an allergy to amide local anesthetics pre-existing coagulopathy or thrombocytopenia <100,000 refusal of analgesic block for pain management presence of an progressive lower extremity neurological deficit localized or systemic infection chronic use of high dose opioid analgesics (defined as daily use greater than 60 mg oxycodone equivalents) pregnant refusal of consent