Total Hip Arthroplasty (THA) or Total Knee Arthroplasty (TKA)

The purpose of this study is to determine whether a single nerve block given before surgery can help patients regain independence and mobility more quickly after planned hip or knee replacement surgery for osteoarthritis. Patients undergoing hip replacement will receive a PENG block, while patients undergoing knee replacement will receive an adductor canal block (ACB). Both procedures will be performed using ultrasound guidance. Some patients will receive a control procedure instead of the active nerve block. All participants will receive standard pain treatment and postoperative rehabilitation. The main aim of the study is to compare patients' functional independence approximately 24 hours after surgery. Other outcomes will include the ability to walk independently, performance during physiotherapy, muscle strength, pain intensity, opioid use, adverse events, and readiness for hospital discharge. Participants will be followed from the preoperative visit until 90 days after surgery. The results of this study may help determine whether these nerve blocks are a safe and effective way to support early recovery and restoration of mobility after hip or knee replacement surgery.