Low-Volume Pericapsular Nerve Group (PENG) Block With Dexamethasone vs Standard-Volume PENG Block After Total Hip Arthroplasty

From the registry

The goal of this clinical trial is to compare two regimens of the pericapsular nerve group (PENG) block, an ultrasound-guided injection of local anaesthetic targeting the nerves supplying the front of the hip joint, for postoperative pain relief and quadriceps muscle function in patients undergoing primary unilateral total hip arthroplasty under spinal anaesthesia. The PENG block was originally proposed as a motor-sparing technique. However, the standard 20 mL volume can spread to the femoral nerve and cause quadriceps weakness. Reducing the injected volume may limit this spread and better preserve quadriceps strength, but smaller volumes risk shorter analgesic duration. Adding dexamethasone to a low-volume injection may compensate for the reduced volume. The main questions this trial aims to answer are: * Does a low-volume PENG block (10 mL bupivacaine 0.25%) with 4 mg dexamethasone differ from a standard-volume PENG block (20 mL bupivacaine 0.25%) in the time to first rescue analgesia? * Does it differ in the incidence and severity of quadriceps weakness on the operated side?…