This study aimed to evaluate the efficacy of ultrasound-guided transmuscular quadratus lumborum block (QLB) combined with local infiltration analgesia (LIA) for pain management and recovery in patients who have undergone total hip arthroplasty (THA) via a posterolateral approach.

This was a prospective, randomized controlled trial.

We collected data in the preoperative area, operating room, and bed ward.

A total of 80 patients with American Society of Anesthesiology functional status scores of II-III were included and assigned to two groups, and all 80 patients were included in the final analysis.

All included patients were randomly assigned to the nerve block (group N) or the control group (group C). Patients in the group N received transmuscular QLB combined with LIA, while patients in the group C received only LIA.

The primary outcome was postoperative pain during the first active motion: it was measured at six hours after surgery and assessed using a visual analog scale (VAS). Secondary outcomes were the resting VAS scores in the post-anesthesia care unit (PACU) and at 2, 6, 12, 24, 48, and 72 h after surgery; VAS scores during motion at 12, 24, 48, and 72 h after surgery; intraoperative consumption of opioids; postoperative consumption of morphine hydrochloride; frequency of sleep interruption due to pain on the night of surgery; time until the first “walk out of the bed” after surgery; muscle strength of the quadriceps femoris; and postoperative adverse effects.

Compared to the group C, patients in the group N had significantly lower VAS scores during motion at 6, 12, and 24 h after surgery, as well as lower resting VAS scores in the PACU and at 2, 6, 12, and 24 h after surgery. Patients in the group N also consumed significantly smaller amounts of intraoperative opioids and morphine after surgery. Patients in the group N reported significantly fewer interruptions in sleep due to pain on the night of surgery and were able to “walk out of the bed” significantly earlier than those in the group C. There was no significant difference between the two groups in muscle strength of the quadriceps femoris or incidence of postoperative adverse effects.

Compared to treatment with LIA alone, ultrasound-guided transmuscular QLB combined with LIA can provide better postoperative pain relief and enhance the recovery of THA patients, since it does not cause quadriceps femoris muscle weakness and is associated with significantly lower need for intraoperative opioids.