OBJECTIVE To evaluate the clinical efficacy of waist and knee simultaneous scraping therapy for knee osteoarthritis (KOA) of cold-dampness obstruction syndrome, and to preliminarily explore its possible mechanism based on serum metabolomics.

METHODS Seventy-two patients with KOA of cold-dampness obstruction syndrome were enrolled from April to August 2025 at the Affiliated Hospital of Nanjing University of Chinese Medicine, and randomly divided into an experimental group and a control group , with 36 cases in each group. Finally, 34 cases in each group completed the study. Both groups received basic education on disease health and exercise rehabilitation. The control group received additional topical application of diclofenac diethylamine emulsion in addition to the basic education, while the experimental group received additional scraping therapy for the waist and knees in addition to the basic education. The treatment course for both groups was 4 weeks, with a 1-month follow-up after treatment. Western Ontario and McMaster Universities Arthritis Index (WOMAC) scores, Lequesne scores, TCM syndrome scores, and clinical efficacy were assessed before treatment, on day 28 of treatment, and at 1-month follow-up. Meanwhile, 34 non-KOA subjects were included as a normal control group. Ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) was used to analyze and compare the serum metabolic profiles of the experimental group before and after treatment and those of the normal control group.

RESULTS On day 28 of treatment and at the 1-month follow-up, the total WOMAC and Lequesne scores as well as the total TCM syndrome scores in both groups were significantly improved compared with those before treatment (P<0.01). Furthermore, the improvements in the experimental group were significantly superior to those in the control group at the same time points (P<0.01), and the total clinical effective rate of the experimental group was significantly superior to that of the control group (P<0.05, P<0.01). No adverse reactions related to the study medications or scraping therapy occurred in either group during treatment. Serum metabolomics analysis identified 169 significantly differential metabolites between the experimental group before treatment and the normal control group, 98 of which were significantly reversed in the experimental group after treatment. These metabolites were primarily involved in 8 metabolic pathways, including ascorbate and aldarate metabolism, valine, leucine and isoleucine degradation, and pentose and glucuronate interconversions, which are mainly associated with antioxidant, anti-inflammatory, and cartilage matrix metabolism.

CONCLUSION Waist and knee simultaneous scraping therapy effectively alleviates the clinical symptoms of cold-dampness obstructive KOA, which may be attributed to the regulation of organismal metabolism and the subsequent modulation of antioxidant, anti-inflammatory, and cartilage matrix metabolic pathways.