The goal of this clinical trial is to evaluate the effectiveness and safety of an autologous platelet-rich concentrated growth factor (CGF) preparation kit for the treatment of knee osteoarthritis in patients diagnosed with this condition. The main question it aims to answer is:

Can the CGF preparation kit effectively improve symptoms and reduce pain in patients with knee osteoarthritis compared to a control intervention? Researchers will compare the CGF treatment group to a control group using platelet-rich plasma (PRP) to see if the CGF intervention results in greater improvements in knee function and pain relief.

Participants will:

Undergo three intra-articular injections of CGF or PRP into the knee joint at weekly intervals.

Complete assessments including the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) and Visual Analog Scale (VAS) for pain at specified intervals.

Be monitored for safety and potential adverse events throughout the study period.

Study design: Prospective, multicenter, single-blind, randomized controlled, non-inferiority clinical trial.

Sample size: 104 cases, with 52 cases in the experimental group and 52 cases in the control group.

This study predefines the conversion between non-inferiority and superiority tests: first, a non-inferiority test is performed. If the non-inferiority conclusion is valid, a superiority test can be performed. If the superiority conclusion is valid, the research conclusion is superiority; if the superiority conclusion is invalid, the research conclusion is non-inferiority.

Inclusion Criteria:

• Age ≥ 18 years, with no gender restrictions;
• Patients diagnosed with knee osteoarthritis according to the "Chinese Guidelines for the Diagnosis and Treatment of Osteoarthritis (2024 Edition)" by the Chinese Osteoarthritis Diagnosis and Treatment Guidelines Expert Group;
• Radiographic evidence of knee osteoarthritis with Kellgren-Lawrence grading of II to IV;
• Visual Analog Scale (VAS) pain score ≥ 4 (moderate or higher pain) and WOMAC score ≥ 24;
• For participants with eligible bilateral knee osteoarthritis, the more severely affected knee will be treated, while the other knee will not be intervened during the study period. If the severity is equal on both sides, the left knee will be selected for intervention;
• The patient or their legal guardian is able to understand the purpose of the study and provide informed consent.

Exclusion Criteria:

• Patients with a confirmed diagnosis of other inflammatory diseases of the knee joint, such as rheumatoid arthritis, psoriatic arthritis, or gouty arthritis; Patients with a confirmed diagnosis of bleeding disorders (e.g., allergic purpura, hemophilia, idiopathic thrombocytopenic purpura), hematologic malignancies (e.g., leukemia), or those with unconfirmed bleeding disorders but coagulation dysfunction (coagulation parameters PT, APTT, INR > 1.5 times the upper limit of normal);
• Patients who have undergone or are planned to undergo knee osteoarthritis surgery within the past 6 months or during the trial period;
• Patients with local infections at the injection site (e.g., septic arthritis, tuberculous arthritis, or local soft tissue infections) or severe systemic infections (e.g., sepsis);
• Patients with untreated malignant diseases such as malignancies, which may interfere with the safety and efficacy assessments of the study and affect the patient's participation in the study;
• Patients with severe hepatic or renal dysfunction [hepatic function indicators alanine aminotransferase (ALT), aspartate aminotransferase (AST) > 2 times the upper limit of normal; renal function indicators serum creatinine (Cr), blood urea nitrogen (BUN) > 2 times the upper limit of normal];
• Patients with hemoglobin < 10 g/dL or platelet count < 125 × 10^9/L;
• Patients who have used any Chinese or Western medications or therapies for the treatment of knee osteoarthritis within 1 week prior to randomization;
• Patients who have received intra-articular injections or related drug therapies within the past 3 months;
• Women who are planning a pregnancy, breastfeeding, or pregnant during the entire clinical study period;
• Patients who have participated in other interventional drug or medical device clinical trials within 1 month prior to enrollment;
• Other situations where the investigator deems the patient unsuitable for participation in this study.

As the primary outcome measure of this study relies on subjective evaluation by the participants, a single-blind design is adopted to avoid bias introduced by participants' evaluations. During the informed consent process, investigators should clearly inform participants that they will be randomly assigned to one of the two treatment groups, but they will not be informed of which group they have been allocated to until the end of the study.