Efficacy of IPACK Block Combined With Intra-articular Steroid Injection in Advanced Knee Osteoarthritis: A Retrospective Cohort Study

Patients presenting to a tertiary hospital in Istanbul, Turkey, between January 2024 and September 2025 with knee pain and diagnosed with stage 3-4 knee osteoarthritis based on clinical and radiological findings were scheduled for the procedure. The procedure was performed on only one knee, and the contralateral knee was not treated.

On the morning of the procedure, patients' NRS-11 and WOMAC scores were recorded. After being taken to the operating room, patients were placed in the supine position. Electrocardiography, pulse oximetry, and non-invasive blood pressure monitoring were performed. Intravenous access was established. The painful knee area was prepared and draped in a sterile manner using a povidone-iodine-based solution. Ultrasonography (US) was used to visualize the knee joint and surrounding structures.

In patients undergoing intra-articular steroid injection (IASI), a 22-gauge, 90-mm needle was advanced from the suprapatellar region into the joint space under ultrasound guidance. After puncturing the joint capsule, a mixture of 4 ml of 1% lidocaine and 40 mg of triamcinolone acetonide was injected into the joint.

Patients undergoing IASI + IPACK (infiltration between the popliteal artery and the posterior capsule of the knee) block were also placed in the supine position with standard monitoring and sterile preparation. First, the IASI procedure was performed as described above. Then, a pillow was placed under the knee to achieve approximately 30° of flexion. Using an ultrasound-guided medial approach, the probe was positioned approximately 2-3 cm above the patella level, starting from the distal medial femoral epicondyle. Subsequently, a 22-gauge, 90-mm needle was advanced to the space between the posterior joint capsule and the popliteal vessels at the level where the femoral condyles end and the femoral shaft begins. A total of 15 mL of a mixture containing 0.25% bupivacaine and 4 mg dexamethasone was injected.

After the procedure, patients were observed in the inpatient ward for at least 2 hours to monitor for potential adverse effects. One week after the injection, all patients were provided with an exercise booklet to guide their home-based rehabilitation program.

Patients were advised to use 500 mg paracetamol (up to four tablets per day) as needed for pain control. They were instructed not to take any analgesics on the day of follow-up assessments, as this could affect clinical outcome measures. Paracetamol consumption was recorded at the end of the 1st and 6th months. NRS-11 and WOMAC scores were also recorded at the 1st and 6th months during outpatient clinic visits.

Inclusion criteria

• Patients over 40 years of age
• Diagnosed with primary knee osteoarthritis according to ACR (American College of Rheumatology) criteria based on clinical, radiological, and laboratory evaluations
• Activity VAS score of 5 or higher despite previous medical and physical therapy
• Patients with stage 3-4 knee osteoarthritis according to the Kellgren-Lawrence classification
• Patients without motor or sensory loss on neurological examination
• Patients who signed an informed consent form
• Patients who have not undergone any interventional procedures on the knee within the last 6 months

Exclusion criteria

• Patients with bleeding or coagulation disorders
• Patients with sepsis or local infection at the intervention site
• Patients with allergies to any of the medications to be used
• Patients without study consent
• Patients with secondary osteoarthritis
• Patients who have undergone knee interventions in the last 6 months
• Patients who have undergone knee surgery
• Psychosis