The goal of this observational study is to learn about the effectiveness of different locoregional anesthesia techniques, particularly the Quadro-Iliac Plane (QIP) block, in patients undergoing total hip arthroplasty. The main question it aims to answer is:

Does the QIP block improve postoperative recovery and pain control compared to other routinely used locoregional anesthesia techniques in patients undergoing hip replacement surgery?

Participants undergoing hip arthroplasty as part of their standard clinical care will receive one of the locoregional anesthesia techniques already in use at the hospital (including QIP block, fascia iliaca block, PENG block, or others, according to anesthesiologist choice). Postoperative outcomes will be collected prospectively, including quality of recovery (QoR-15 at 24 hours), pain scores at rest and during movement at predefined time points up to 48 hours, analgesic consumption, time to first analgesic request, time to mobilization, and occurrence of complications.

This prospective, observational, non-interventional clinical study will evaluate postoperative recovery and analgesic outcomes in adult patients undergoing hip arthroplasty who receive locoregional anesthesia techniques already used in routine clinical practice.

The study focuses particularly on the Quadro-Iliac Plane (QIP) block, a recently introduced fascial plane block performed at the posterior-inferior aspect of the quadratus lumborum muscle near its insertion on the iliac crest. The QIP block will be assessed in comparison with other locoregional techniques routinely used for hip surgery, including fascia iliaca block, PENG block, sacral or lumbosacral erector spinae plane block, femoral nerve block, sciatic nerve block, lumbar plexus block, neuraxial anesthesia, or combinations of these techniques.

Patients will not be randomized, and the choice of anesthetic and analgesic technique will be made by the attending anesthesiologist according to standard clinical practice. All blocks will be ultrasound-guided and performed under aseptic conditions using approved local anesthetics. Standard perioperative monitoring, spinal anesthesia when appropriate, postoperative multimodal analgesia, and rescue analgesia will be provided according to institutional protocols.

The primary endpoint will be postoperative quality of recovery, assessed using the Quality of Recovery-15 score 24 hours after surgery. Secondary outcomes will include postoperative pain scores at rest and during movement at predefined time points up to 48 hours, patient satisfaction, total analgesic consumption, time to first rescue analgesic request, time to first mobilization, nausea and vomiting, antiemetic use, and block-related or postoperative adverse events. Safety monitoring will include immediate complications during block performance, early post-block complications, and delayed neurological symptoms assessed up to 7 days after surgery.

The study plans to include at least 40 patients, with a possible sample size of 40-80 cases, and an expected maximum study duration of 18 months.

Inclusion Criteria:

• Age ≥ 18 years
• Patients undergoing hip arthroplasty surgery, either elective or for a proximal femoral fracture
• Expected postoperative hospital stay ≥ 24 hours
• ASA physical status I-III
• Neuraxial and/or locoregional anesthesia according to standard clinical practice
• Provision of informed consent to participate in the study

Exclusion Criteria:

• Absence of informed consent
• Contraindications to locoregional and/or spinal anesthesia
• Allergy to local anesthetic agents
• Cognitive impairment preventing reliable assessment of outcomes
• Coagulation disorders and/or platelet abnormalities
• Antiplatelet or anticoagulant therapy that contraindicates spinal anesthesia
• Presence of localized infection or sepsis at the sites to be treated

Patients undergoing hip arthroplasty surgery, either elective or for a proximal femoral fracture