Total knee arthroplasty (TKA) is a frequently performed major orthopedic surgery, where most patients experience severe postoperative pain. Pain-related delays in patient mobilization can lead to thromboembolism, deep vein thrombosis, surgical site infection, and increased risk of hospital-acquired infections due to prolonged hospital stay. Optimal postoperative knee analgesia is crucial not only for patient comfort and satisfaction but also for accelerating mobilization, functional recovery, and discharge from the hospital. To facilitate early ambulation and superior performance, multimodal analgesia and motor-sparing blocks are increasingly utilized

In total knee arthroplasty, a pain management method that preserves motor strength is increasingly accepted as part of the perioperative rehabilitation protocol. Although peripheral nerve blocks like the femoral nerve block (FNB) can cause significant loss of quadriceps muscle strength and delayed rehabilitation due to the risk of patient falls, growing evidence supports the use of the Total knee arthroplasty (TKA) is a frequently performed major orthopedic surgery, where most patients experience severe postoperative pain. Pain-related delays in patient mobilization can lead to thromboembolism, deep vein thrombosis, surgical site infection, and increased risk of hospital-acquired infections due to prolonged hospital stay. Optimal postoperative knee analgesia is crucial not only for patient comfort and satisfaction but also for accelerating mobilization, functional recovery, and discharge from the hospital. To facilitate early ambulation and superior performance, multimodal analgesia and motor-sparing blocks are increasingly utilized.

Regional anesthesia techniques are among the most effective methods for postoperative analgesia. Peripheral nerve blocks, a type of regional anesthesia, provide ideal postoperative analgesia due to their ability to offer effective analgesia, reduce opioid requirements and associated side effects, and facilitate recovery by effectively managing dynamic pain.

The innervation of the knee joint is supplied by branches from the femoral nerve, obturator nerve, common peroneal nerve, and tibial nerve, which originate from the lumbar and sacral plexuses responsible for lower extremity innervation.

adductor canal block (ACB) in total knee arthroplasty patients for minimal motor involvement or purely sensory block.

The adductor canal block (ACB) is a predominantly sensory nerve block that includes the saphenous nerve, the nerve to the vastus medialis muscle, and the articular branches of the obturator nerve. When performed successfully, it provides analgesia similar to the femoral nerve block without significant motor loss in the thigh. It is primarily used for lower extremity surgeries such as total knee arthroplasty, anterior cruciate ligament reconstruction, and meniscus repair.

There is increasing interest in the technique called iPACK (infiltration between the popliteal artery and capsule of the knee), which involves injecting local anesthetics into the space between the popliteal artery and the posterior capsule of the knee. This approach blocks the terminal branches of the genicular nerves and the popliteal plexus, which innervate the posterior capsule of the knee, while sparing the main trunks of the tibial and common peroneal nerves. Therefore, the iPACK block appears advantageous by providing motor-sparing posterior knee analgesia with a lower likelihood of nerve or vascular injury under ultrasound guidance. Studies have shown that combining ACB with the iPACK block provides significantly better postoperative numerical rating scale (NRS) scores, knee range of motion, and ambulation distances compared to ACB alone.

Inclusion Criteria:

1. Patients with written informed consent
2. Patients over 18 years old undergoing elective total knee arthroplasty surgery
3. Patients with ASA I-II-III
4. Patients receiving spinal anesthesia

Exclusion Criteria:

1. Revision knee arthroplasty and bilateral total knee arthroplasty
2. Liver or kidney failure
3. Patients under 18 years old
4. Patients receiving general anesthesia
5. Allergy or intolerance to study medications
6. Body mass index (BMI) > 40 kg/m²
7. Chronic use of gabapentin/pregabalin (regular use for more than 3 months)
8. Chronic opioid use (opioid use for more than 3 months or daily oral morphine equivalent > 5 mg/day for 1 month)
9. Patients with ASA IV and those undergoing emergency surgery

Once eligibility is confirmed, patients will receive complete oral and written information about the study. Informed consent will be obtained before randomization and study-specific procedures.