Comparative Study between Ultrasound Guided Intraarticular Injection of Corticosteroids and Ultrasound Guided Genicular Nerve Block in Patients with Chronic Knee Pain
Authors: Kamel El Sirafy Mohammed Amin Mohammed , Edward Abdelmalek Mina Emil , Mousa Ebied Ahmed Ibrahim , Abdel Hamid Hetta Walid Mohamed 
Published: July 2024

Abstract

Background
Chronic knee pain represents a major cause of disability and a burden on healthcare systems worldwide, being more prevalent in middle-aged and elderly patients. It can take a toll on patients’ daily life, keeps them from their favorite activities, saps of productivity, and diminishes overall quality of life. It can be caused by degenerative conditions, such as osteoarthritis (the most common cause), rheumatoid arthritis, crystalline arthritis and gout. lifestyle modification, pharmacologic management, and injections are the mainstay of therapy for elderly patients having chronic symptomatic knee pain with multiple medical comorbidities who do not wish/fit for surgical options. Intra-articular corticosteroid injection (IACSI) was commonly adopted to alleviate chronic knee pain and was traditionally performed blindly depending only on anatomical land marks. Recently, Genicular nerve block (GNB) has recently emerged as a novel alternative treatment for chronic knee pain. Both Intra-articular corticosteroid injection (IACSI) and Genicular nerve block (GNB) can be carried out under Ultrasound guidance as a safer, cheaper and more feasible imaging modality for guidance as it provides real-time imaging for the knee structures in a dynamic manner giving the ability to do interventional procedures and providing more effective clinical results when compared to blind injections.

Aim of the Work
Illustrate the technical aspects, the indications and the methodology of local therapies for chronic knee pain performed by interventional radiologists and provide current evidence. Assess the efficacy of Ultrasound (US) guided intraarticular corticosteroids injection and Genicular nerve block to control moderate and advanced chronic knee pain. Compare the immediate and short-term symptomatic and functional improvement obtained after both techniques.

Patients and Methods
The study was carried out on 30 patients of symptomatic chronic knee pain with radiologically proven knee joint arthritis (26 of them had osteoarthritis, 3 had gout arthritis and one patient had rheumatoid arthritis), all of them were not responding to medical treatment. They were divided into two groups (intraarticular corticosteroids injection group and Genicular nerve block one) both procedures were performed under ultrasound guidance to identify target points for injection. GNB target points for injection where close to the superior lateral, superior medial and inferior medial genicular arteries while target point for the IACSI group was the suprapatellar bursa. All procedures were performed with a spinal needle (22 G) introduced under ultrasound guidance till reaching the desired target points at both groups. Then injection of a mixture of Lidocaine, Bupivacaine hydrochloride and Triamcinolone Acetonide was done.

Results
In our study, in IACSI group the mean of initial VAS was 80.7±10.3 compared to 81.3±7.7 in GNB group. The mean VAS significantly dropped to be 20.7±5.3 in IACSI group compared to 18.3±5.9 in GNB group. After 2 weeks, it was 34.3±8.4 and 27.7±8.2 respectively. After 4 weeks, it increased to 40±8.7 and 33.7±9.3 respectively. At 8 weeks, it was obviously increased to 75.3±10.3 and 66.7±11.4 respectively and the effect returned gradually till nearly the baseline at 8 weeks. In our study, in IACSI group the mean of initial OKS was 48.6±7.4 compared to 50.1±7.6 in GNB group. After 2 weeks, it was markedly decreased to 25.5±3.9 and 22.7±6.8 respectively. After 4 weeks, it increased to 31.1±3.5 and 27.±6.9 respectively. At 8 weeks, it was obviously increased to 44.1±7.1 and 39.3±6.1 respectively and the effect returned gradually till nearly the baseline at 8 weeks.

Conclusion
Ultrasound guided genicular nerve block with a mixture of corticosteroid and local anesthetic is an effective, radiation free method to alleviate chronic knee pain and improve knee joint function. US guided intra-articular corticosteroid injection through suprapatellar approach is also an effective method to relive chronic knee pain and inflammation and to improve knee joint functional capacity. Both procedures are effective in alleviation of chronic knee pain for up to 4 weeks with marked decrease in VAS score after 2 weeks and slight increasing trend towards 4 weeks. The favorable effect returned gradually till nearly the baseline at 8 weeks. Genicular nerve block is more effective than intra-articular corticosteroid injection in both pain alleviation and improving knee joint function.
The earlier the Kellgren- Lawrence score is, the more reduction in chronic knee pain and the more improvement of joint function is achieved after both procedures.