Ultrasound guided intra-articular botulinum toxin injection for treatment of the osteoarthritic knee pain: expert opinion.

Osteoarthritis is the most common form of arthritis and cause of joint pain and disability [1]. The prevalence, burden and socioeconomic impact of osteoarthritis of the knee is considerable and growing [2]. Knee pain is the most cardinal symptom of the osteoarthritic knee and is associated with a high degree of impaired function and daily activities [3]. Intra-articular injection provides a safe and cost effective control of knee pain with improvement of function and activities of daily living [4]. Ultrasound guidance improves the accuracy of the intra-articular injection in knee joint and clinical outcomes and lowers health care costs [5]. Botulinum toxin targets many neuropeptides leading to reduction of pain, peripheral sensitization and in turn reduction of the central sensitization. Also, botulinum toxin plays an anti-inflammatory role by reduction of the neurogenic inflammation [6]. The following table summarizes how to use botulinum toxin in clinical practice according to authors experience. However, further large-scale multicenter randomized controlled trials are needed to confirm effectiveness and determine the exact position of this intervention in the therapeutic armamentarium for the osteoarthritic knee pain.