Long-Term Study of CartiPRO for Knee Pain Due to Osteoarthritis or Cartilage Damage

Inclusion Criteria * Age 19 years and older * Diagnosed with unilateral or bilateral knee osteoarthritis according to American College of Rheumatology (ACR) criteria, with at least 3 of the following 6 features: * Age ≥50 years * Morning stiffness \<30 minutes * Crepitus on active motion * Bony tenderness * Bony enlargement * No palpable warmth * Radiographic evidence of Kellgren-Lawrence grade I, II, or III osteoarthritis within 6 months prior to screening or at screening visit * Weight-bearing pain Visual Analogue Scale (VAS) score ≥40 mm in at least one knee joint at screening * Able to walk without assistive devices (walkers or canes), OR if using a walking aid routinely for past 6 months, able to continue using the same device throughout the study * Able to understand and complete efficacy assessment questionnaires * Willing and able to provide written informed consent Exclusion Criteria * Body Mass Index (BMI) ≥32 kg/m² * Chronic inflammatory joint disease (e.g., rheumatoid arthritis) * Inflammatory joint disease (e.g., septic arthritis) * Secondary knee osteoarthritis due to ochronosis, hemochromatosis, or systemic disease * Painful musculoskeletal conditions (e.g., Sudeck's atrophy, Paget's disease, herniated intervertebral disc) * Polyarticular disease with severe osteoarthritis in other joints (e.g., hip) that may affect knee pain evaluation * Radiographic evidence of definite loss of patellofemoral joint space * Moderate to severe joint effusion confirmed by positive patellar tap test or equivalent * History of myocardial infarction, congestive heart failure, other serious cardiac disease, or uncontrolled hypertension (≥140/90 mmHg despite treatment with ≥3 antihypertensive agents) * History of autoimmune disease * Active infection requiring parenteral antibiotics * History of psychiatric disorder or epilepsy * Cancer diagnosis within 5 years prior to screening * Uncontrolled type 1 or type 2 diabetes mellitus (HbA1c \>7%) * Surgical procedures (including arthroscopy) on target knee within 1 year (surgery on contralateral knee or hip may be exclusionary if it could affect target knee assessment) * Intra-articular corticosteroid injection into target knee within 12 weeks * Systemic corticosteroid use within 4 weeks (topical and inhaled corticosteroids permitted) * Surgery or radiation therapy to knee joint within 12 weeks, or not fully recovered from side effects * Immunosuppressive therapy (e.g., Cyclosporine A, Azathioprine) within 6 weeks * Intra-articular injections (e.g., hyaluronic acid) into knee joint within 6 months * Prohibited concomitant medications within 2 weeks (unless washout period is adequate) * Anticoagulants (e.g., warfarin, NOACs), antiplatelet agents (e.g., aspirin \>100 mg/day, clopidogrel; low-dose aspirin ≤100 mg/day permitted), thrombolytic agents (e.g., urokinase, alteplase), or Vitamin E \>1000 IU/day within 2 weeks (unless adequate washout) * Habitual use (≥3 months) of psychoactive drugs or narcotic analgesics that may affect pain perception * History of cell therapy or gene therapy to target joint * Planned cell therapy or gene therapy to target joint * Abnormal laboratory values at screening: * ALT, AST, BUN, or serum creatinine \>2× upper limit of normal * Engaged in high-intensity aerobic or heavy anaerobic exercise that may affect the knee joint * Dermatological disease at injection site or site deemed unsuitable for injection * Ligament instability of Grade II or higher in target knee (Grade 0: none; Grade I: 0-5 mm; Grade II: 5-10 mm; Grade III: \>10 mm) * Known hypersensitivity to investigational product or its components * Pregnant or breastfeeding women * Women or men of childbearing potential unwilling to use acceptable contraception during study (acceptable methods: intrauterine device, tubal ligation, sterilization surgery, condom or diaphragm with spermicide, natural family planning) * Participation in another clinical trial within 4 weeks * Cognitive impairment or dementia preventing informed consent * Any other condition that makes the subject unsuitable for study participation per investigator judgment