Total hip arthroplasty is a major surgical procedure performed on a growing number of patients. Optimal pain control with limited muscle weakness is paramount for a swift initiation of physical therapy and ambulation, thus expediting hospital discharge. Amongst the many peripheral nerve blocks, FIB (fascia iliaca block) has been recommended as the block of choice by many international guidelines since it offers the best pain control with a relatively low risk of motor block. PENG (pericapsular nerve group) and its association with LFCN (lateral femoral cutaneous nerve) has been proposed as an effective alternative that offers comparable, If not better, pain control with a considerably lower risk for motor block compared to FIB. Given the novelty of this block, there are few published papers on the subject, mostly case series or case reports thus justifying the need for retrospective study.

The primary outcome was the degree of residual quadriceps femoris muscle paresis assessed with the MRC (medical research council) scale at 6 hours between PENG and LCFN. The secondary outcomes were NRS (numeric rating scale) at 6,12, 24 hours, total opioid consumption expressed as milligrams of morphine equivalents (MME), time to first rescue opioid and time to first postoperative ambulation.

Inclusion Criteria:

• elective total hip replacement surgery for non-traumatic hip disease,
• age over 18 years,
• complete clinical chart including type of peripheral nerve block performed,
• signed consent form for spinal anesthesia and peripheral nerve block.

Exclusion Criteria:

• preoperative opioid therapy,
• having received a peripheral nerve block other than PENG + LFCN or FICB,
• having received general anesthesia,
• incomplete chart,
• documented muscle weakness
• deviation from the established post-operative analgesia protocol.

Historical cohort study conducted among all patients who had THA from November 2022 to October 2023 at the ASST Nord Milano - Bassini Hospital, Cinisello Balsamo, Milano, Italy.