Perineural Prolotherapy in Chronic Knee Osteoarthritis Pain.

Inclusion Criteria: 1. Patients of both sexes 2. Age \>38 years 3. Body Mass Index (BMI) up to 42 kg/m2 4. Diagnosis of knee osteoarthritis, according to the clinical criteria of the American College of Rheumatology. Osteoarthritis if the following combinations are present: A, B, C, D or A, B, E or A, D, E: A) Knee pain most days of the previous month B) Cracking during active joint movement C) Morning stiffness lasting at least 30 minutes D) Age at least 38 years E) Bone swelling of the affected knee on physical examination 5. Chronic knee pain on the Numerical Rating Scale (NRS) \> 5 for at least 3 months prior to the study 6. Grade 2 or 3 osteoarthritis, according to the Kellgern-Lawrence classification 7. Pain, creaking, and stiffness in the knee joint that persists for at least three months prior to the study. Exclusion Criteria: 1. Any infection of the skin of the knee joint, such as cellulitis, or periarticular or intraarticular infection during the last 3 months 2. Poorly controlled diabetes mellitus or connective tissue disease affecting the knee joint 3. History of previous total knee arthroplasty or other knee surgery. 4. History of periarticular or intraarticular injection of corticosteroids, local anesthetic, hyaluronic acid, platelet-rich plasma, radiofrequency, prolotherapy within the last trimester 5. History of knee injury or fracture within the last 3 months 6. History of acute lumbosacral radiculopathy or peripheral neuropathy, neurological, psychiatric disease 7. Pain limited in the posterior aspect of the knee 8. History of limb malignancy 9. History of bleeding disorder 10. Pregnancy 11. Allergy to local anesthetics, needle phobia 12. Difficulty communicating (severe hearing loss, dementia, language problems) 13. Non-guaranteed transportation to hospital for treatments and re-evaluations