Pain in the knee is a sign of pathological processes affecting the cartilage, bone or soft tissue structures of the femoral-tibial and femoral-patellar joints. Arthralgia can be based on injuries, inflammatory and degenerative diseases of the articular apparatus and periarticular structures. Patients may complain of sharp, aching, burning, throbbing and other types of pain that occur at rest or when moving, supporting, bending and unbending the leg at the knee. Diagnosis of causative pathology includes methods of instrumental imaging (Rg, ultrasound, CT or MRI, arthroscopy), puncture of the articular bag, biochemical and immunological analyzes. Until the diagnosis is clarified, rest, joint immobilization, NSAIDs and analgesics are recommended.