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

Overview

Osteoarthritis is the insufficiency of joint cartilage resulting from the interaction of genetic, metabolic, and biochemical factors, and is accompanied by secondary inflammation. This condition is a pathological process involving the interactive damage and repair of cartilage, bone, and synovium. Osteoarthritis is the most common joint disease worldwide and causes the greatest physical disability. The most prominent symptom is pain. It typically increases with activity and decreases with rest. As the disease progresses, the pain becomes more pronounced with lighter activity, eventually occurring at rest and at night. The knee joint is a synovial joint formed between the femoral condyles and the tibia. Sensory innervation of the knee joint is provided by branches of the femoral, obturator, and sciatic nerves. Pain from knee osteoarthritis is a common problem that can cause disability and impair quality of life. In many patients with chronic knee pain due to osteoarthritis, pharmacological methods and/or physical therapy may not provide adequate analgesia. Knee arthroplasty is the most frequently used treatment option for advanced knee osteoarthritis. However, it is sometimes not applicable due to patient comorbidities. The most commonly used interventional method for analgesia in knee osteoarthritis today is intra-joint steroid injection. This slows inflammation in the cartilage and can prevent osteophyte formation. However, frequent steroid injections can lead to both short-term pain relief and osteoporosis in the bone. In recent years, different alternatives for the treatment of osteoarthritis-related knee pain have become prominent. The nerves that provide pain sensation to the knee joint originate from both the anterior and posterior sides. The IPACK block, a simple, practical method performed under ultrasound guidance, is often thought to block the area innervating the posterior knee, but cadaver studies suggest that the anterior geniculate nerves are also blocked. This can be an alternative treatment option for additional analgesia in patients with advanced knee osteoarthritis.The aim of this study is to investigate the effects of IPACK block combined with steroid injection into the knee joint on pain scores in painful patients diagnosed with chronic knee osteoarthritis.

Patients presenting to the Algology Outpatient Clinic of Istanbul Cemil Taşçıoğlu City Hospital between January 2024 and September 2025 with knee pain and diagnosed with stage 3-4 knee osteoarthritis based on clinical, radiological, and laboratory tests were scheduled for the procedure. The procedure was performed on only one knee; the second 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 povidone-iodine-based solution. Ultrasonography (US) was used to image the knee joint and its surrounding area. In patients undergoing knee steroid administration (IASI), a 22-gauge, 90-mm needle was advanced from the suprapatellar area to the joint space under ultrasound guidance. The joint capsule was punctured, and 40 mg of triamcinolone acetonide was injected into the joint. Patients undergoing IASI+IPACK (infiltration of the space between the popliteal artery and the posterior knee capsule) block were placed in the supine position, in accordance with monitoring and sterilization guidelines. Following the same procedure as described above, the knee was first IASI performed, and a pillow was placed under the knee at 30 degrees of flexion. After imaging the knee joint space with an US-guided medial approach, the probe was advanced approximately 2-3 cm above the patella level, starting from the distal medial epicondyle of the femur. Then, 15 ml of 0.25% bupivacaine + 4 mg dexamethasone mixture was administered between the joint capsule and the popliteal artery and vein, where the femoral condyles end and the femoral body begins, using a 22-gauge 90 mm needle. After the procedure, patients were observed in our inpatient ward for at least 2 hours to monitor for potential side effects. One week after the injection, all patients were given an exercise booklet to follow their rehabilitation program at home. Patients were advised to use 500 mg of paracetamol (up to four tablets per day) as needed. They were told not to take any analgesics on the day of follow-up assessments, as this could affect clinical outcome measures.Patients were then questioned about their Paracetamol doses used by the patients at the end of the 1st and 6th months were recorded NRS-11 and WOMAC scores at 1 and 6 months during outpatient clinic visits.