Knee osteoarthritis occurs when cartilage within the joint gradually wears down, leading to pain, stiffness, and reduced mobility. In the United States, PRP injections are often considered for patients with mild to moderate osteoarthritis who continue to have symptoms despite conservative treatments such as physical therapy or medications. The procedure involves injecting a concentrated portion of the patient’s own platelets into the knee joint, where they can help regulate inflammation and influence the joint environment. Some clinical studies have reported improvements in pain and function over several months, making PRP a potential non surgical option for selected patients.

Adult holding knee joint with visible discomfort, representing osteoarthritis treated with PRP injection

Platelet rich plasma helps regulate inflammation and stimulate biological repair signals within the knee joint. PRP contains concentrated platelets that release growth factors involved in tissue repair and inflammation control. Growth factors such as platelet derived growth factor, transforming growth factor beta, and insulin like growth factor can influence the activity of chondrocytes, which are responsible for maintaining cartilage tissue. These signals may stimulate production of extracellular matrix components including collagen and proteoglycans that support cartilage structure. PRP also contains cytokines that may reduce inflammatory mediators in synovial fluid. By modifying the biological environment of the joint, platelet rich plasma may help decrease inflammation while supporting cellular processes that contribute to improved joint stability and knee function.

A PRP injection for knee arthritis involves collecting a small blood sample, concentrating platelets using a centrifuge, and injecting the platelet rich plasma into the knee joint. The procedure typically begins with a blood draw of approximately 30 to 60 milliliters from the patient’s arm. The blood is processed in a centrifuge that separates red blood cells from plasma and concentrates platelets within the plasma layer. The resulting platelet rich plasma is then placed into a sterile syringe. Most orthopedic physicians perform the injection using ultrasound guidance so the needle can be accurately placed inside the knee joint space. The procedure usually takes about 20 to 30 minutes in an outpatient clinic. Patients are commonly advised to avoid strenuous activity for several days while the biological healing response begins.

Platelet rich plasma may provide longer lasting symptom improvement than some traditional knee injection therapies. Corticosteroid injections often reduce inflammation quickly but their effects may diminish within several weeks. Hyaluronic acid injections aim to improve joint lubrication and shock absorption within the knee. PRP differs because it delivers concentrated growth factors that influence biological repair processes rather than only suppressing inflammation. Randomized clinical trials have reported improvements in pain scores and knee function for some patients receiving PRP compared with hyaluronic acid injections at follow up periods of six to twelve months. Treatment outcomes can vary depending on the severity of osteoarthritis, platelet concentration, and the injection technique used.

Most orthopedic treatment protocols recommend one to three PRP injections for knee osteoarthritis depending on the severity of symptoms. These injections are commonly spaced two to four weeks apart to allow the biological effects of platelet derived growth factors to influence the joint environment. Some patients notice gradual improvements in knee pain and mobility within four to eight weeks after treatment. Clinical studies have reported symptom improvement lasting six months to one year in certain patients, particularly those with earlier stages of cartilage degeneration. Physicians frequently combine PRP therapy with strengthening exercises, weight management, and physical therapy to support long term joint stability and functional improvement.

Find doctors offering platelet rich plasma treatment for knee osteoarthritis near you.

This information is educational and not a substitute for professional medical advice. Platelet rich plasma treatments are not FDA approved for all orthopedic uses. Patients should consult a licensed U.S. healthcare professional before pursuing treatment.