Complex Network Analysis of Acupoint Combinations in The Treatment of Knee

Abstract

Introduction and Objectives: Osteoarthritis (OA) of the knee is a significant and increasing health problem. In traditional Chinese medicine (TCM), it is categorized as "Bi Syndrome" (Bi Zheng). The main causes are attributed to wind, cold, and dampness (external pathogenic factors) and deficiency of the internal organs, resulting in the stagnation of qi and blood circulation. Acupuncture is a critical treatment that helps alleviate pain and restore knee joint function. The objective of this study was to investigate the patterns of acupoint combinations used in the treatment of knee osteoarthritis, primarily utilizing complex network analysis (CNA) as the main tool to reveal underlying clinical principles.

          Methods: This study employed a documentary research design combined with quantitative analysis. This involved systematically searching for clinical research reports related to acupuncture treatment for knee osteoarthritis published from 2005 to 2023 from the following data sources: CNKI, Wanfang data, and Weipu data. Selected research reports were collected in a data collection form developed in Microsoft 365, comprising the following variables: title, publication year, experimental group, control group, gender, age, concomitant treatment methods, and the names of acupoints used. The results were analyzed using the Gephi program, a tool utilized for the visualization and analysis of complex networks. The network components were defined as nodes, edges, and weights. All analysis results were subsequently discussed by linking the important network metrics: degree centrality, betweenness centrality, and top co–occurrence pairs.

Results: A search for data using the keywords knee osteoarthritis, acupuncture, acupoints, complex network analysis from the CNKI, Wanfang data, and Weipu data databases found 298 research articles. After filtering based on the inclusion and exclusion criteria, 119 articles met the criteria. The resulting network structure analysis comprised 30 nodes (acupoints), 237 edges (pairs), and a total weight of 2,769 counts. The determination of Core Acupoints using degree centrality analysis showed Dubi, Zusanli, Yanglingquan, Neixiyan and Xuehai as the top 5 acupuncture points ranked by frequency of use. These points are the most frequently used in combinations and are considered the core that defines the structure of the treatment network. Strategic bridge points (betweenness centrality) the points with the highest betweenness centrality (BC) are Zusanli and Yanglingquan, which function as bridges linking local treatment with systemic regulation. Distal points – those far from the knee joint and important from the perspective of the meridian system such as Sanyinjiao, Xuanzhong, and Taixi – also showed high BC values. This indicates that these points are crucial intermediaries in connecting local treatment to the systemic balancing of the body within the meridian network. Highest frequency of pairing (top co–occurrence pairs) the pair with the highest co–occurrence frequency was Neixiyan–Dubi, which emphasizes localized treatment. This was followed by pairs that integrate a local point with a distal point. These pairings focus on using local points near the knee to reduce pain and enhance local circulation.

          Discussion: The principle of local focus involves selecting acupuncture points that are local to the area of discomfort, such as Neixiyan and Dubi, both of which are located directly on the knee joint. This pairing emphasizes the principle of local acupoint selection, which involves choosing acupuncture points specific to the area of the symptoms. It urgently stimulates the circulation of qi and blood in the knee joint area to relieve pain and stiffness in the joint. The integration of distal points (systemic integration) is primarily a combination of local points with distal points. Examples include: Zusanli is a point used to tonify qi and nourish the body (e.g., Spleen/Stomach). Yanglingquan is hui–meeting point of the tendons and sinews, aiming to relax the tendons and manage blood stasis. Xuehai is a point used to activate blood circulation, targeting blood stasis, which is a key pathological feature of knee osteoarthritis. This integrated treatment approach aims at relaxing tendons and managing blood stasis, among other pathological factors. The presence of pairs directly linked to whole–system balancing, such as Zusanli–Yanglingquan and Zusanli–Xuehai, serves as a core strategy confirmation. This confirms that even with localized symptoms in the knee, clinical treatment still prioritizes addressing the underlying deficiency of the spleen/stomach and regulating the liver and kidney systems. According to TCM theory, these internal organ disharmonies form the fundamental root cause of knee osteoarthritis.

          Conclusion and Recommendations: This study successfully revealed the systematic structure and underlying rules of acupoint selection for the acupuncture treatment of knee osteoarthritis, which is consistent with TCM theory. The research findings can serve as an evidence–based foundation for the future development of more precise and systematic standards and guidelines for acupuncture treatment. It is recommended that further studies should be conducted with a larger amount of data and, importantly, should directly correlate the findings with clinical outcomes. Future research should specifically focus on randomized controlled trials (RCTs) to validate the efficacy of the core acupoint combinations identified in this network analysis.