Osteoarthritis is the most common musculoskeletal degenerative disease that affects the entire joint [1]. It is an important problem in older adults and exerts a huge socioeconomic burden around the world [2]. Its prevalence is 10% and 18% in men and women over 60 years of age, respectively; moreover, approximately 30% of people over 45 years of age have radiographic signs of knee osteoarthritis, and 15% are symptomatic [3].

The pathology of knee osteoarthritis is complex and affects the entire joint, including cartilage, subchondral bone, synovium, and surrounding muscles and tendons [1]. When cartilage mechanoreceptors sense physical stress, chondrocyte metabolic activity is altered, causing a decrease in the extracellular matrix and irreversible cartilage destruction [4]. In the subchondral bone, remodeling can be seen in response to mechanical stress. Osteoblasts secrete more pro-inflammatory cytokines and degenerative enzymes [5]. Synovial inflammation causes synovial cell proliferation and lymphocyte infiltration [6] and is associated with clinical symptoms [7]. The muscles and tendons surrounding the knee joint are inflamed in patients with knee osteoarthritis [8]. Furthermore, muscle dysfunction around the knee joint is observed, leading to functional limitation [9].

Osteoarthritis can cause pain, loss of mobility, and swollen joints, resulting in poor quality of life. Common treatment methods include non-steroidal anti-inflammatory drugs, intraarticular injections of hyaluronic acid, and surgery [10]. Traditional Chinese medicine therapies, such as acupuncture, can help relieve symptoms of osteoarthritis [11]. The theory behind acupuncture is that when the flow of energy (qi) in the body is interrupted through the various channels (meridian), disease ensues and acupuncture needles are used to stimulate points in the channels (acupuncture points) to restore energy balance and relieve disease [12]. The effect of acupuncture on knee osteoarthritis can be explained in two ways. First, acupuncture activates molecules, such as opioids, to relieve pain and reduce pro-inflammatory cytokines by decreasing COX-2 [13]. Second, it modulates pain by preventing cortical thinning and decreasing the connectivity of neurons in the major areas of the brain related to pain [14].

A unique form of acupuncture called acupotomy was recently recommended for knee osteoarthritis by consensus of Chinese medicine experts [15]. Acupotomy, also known as a needle knife, stiletto needle, and miniscalpel needle, is a combination of microinvasive surgery and acupuncture [16]. It differs from traditional acupuncture in that the needle used in acupotomy has a blade-like structure at the tip [17]. Acupotomy can be used to treat bone hyperplasia and soft tissue inflammation because the blade-like structure can be used to dissect inflamed, adhesive tissue and release tissue tension [18]. Animal studies investigating the biochemical mechanisms of acupotomy have revealed that in addition to its anatomical effects, acupotomy is a promising technique for alleviating osteoarthritis symptoms. It also has an effect on chondrocytes [19]. Acupotomy has been used in China for a long time, but strong evidence of its efficacy remains lacking. Therefore, we conducted a systematic review and meta-analysis of randomized controlled trials (RCTs) to compare the effectiveness of acupotomy and acupuncture in relieving symptoms of knee osteoarthritis.