Platelet-rich plasma injections for knee osteoarthritis

2.1 Osteoarthritis of the knee is the result of progressive deterioration of the articular cartilage and menisci of the joint, usually because of trauma, and wear and tear. This leads to exposure of the bone surface. Symptoms include pain, stiffness, swelling and difficulty walking.

2.2 Treatment depends on the severity of the symptoms. Conservative treatments include analgesics and corticosteroid injections to relieve pain and inflammation, and physiotherapy and prescribed exercise to improve function and mobility. When symptoms are severe, surgery may be indicated: options include upper tibial osteotomy and unicompartmental or total knee replacement.

2.3 Platelet-rich plasma is prepared by a clinician or a technician. Blood is taken from the patient and centrifuged to obtain a concentrated suspension of platelets in plasma. Different preparation methods may affect the concentrations of platelets and the level of contamination with red and white blood cells. Different agents such as calcium chloride or thrombin may be added.

2.4 The platelet-rich plasma is injected into the joint space in the knee, usually under ultrasound guidance. Platelets contain growth factors that are thought to stimulate chondrocyte proliferation, leading to cartilage repair. The aim is to relieve symptoms, potentially delaying the need for joint replacement surgery. This guidance refers to the use of platelet-rich plasma injections alone and not as part of a combination therapy.