Intra-articular injections of platelet-rich plasma to treat knee osteoarthritis do not improve patients’ symptoms.
3% of the population under age 45 has osteoarthritis, 65% after age 65, and 80% over age 80. Osteoarthritis of the knee is characterized by deterioration of the cartilage in the joints of one or both knees. It is a disease that can lead to disability and for which there is no cure. The treatment options available to patients are mainly aimed at slowing the progression of the disease. These are mainly dietary measures such as weight loss or medications to relieve pain during episodes of inflammation. For example, corticosteroid injections into the joint or wearing a knee brace can relieve pain.
Intra-articular injections are no more effective than a placebo
In recent years, another treatment method has been developed: intra-articular injection of platelet-rich plasma, or PRP. Platelets – a type of cell – from the patient’s own blood are injected into the joint. The goal of this treatment is to regenerate the damaged cartilage. However, according to a study published in the journal JAMA Network, these injections are not effective, at least no more effective than a placebo. To reach this conclusion, researchers studied 288 adults at least 50 years old with mild to moderate knee osteoarthritis. Some received intra-articular injections of PRP, while others received only placebo injections.
No improvement in pain or cartilage
After one year, the researchers compared outcomes between the two groups and found no significant difference. Participants who received intra-articular PRP injections experienced almost the same change in pain scores as those who received a placebo. Worse, the average decrease in cartilage volume after one year was -1.4% in the first group versus -1.2% in the placebo group. The researchers, therefore, concluded that this treatment by intra-articular injection of PRP is not effective in patients with knee osteoarthritis, as it does not improve perceived pain or symptoms of this disease after one year.
Femorotibial and femoropatellar OA.
Osteoarthritis of the knee can affect several joints. When it affects the joint between the femur and tibia it is called femorotibial osteoarthritis and is the most common. It may be due to a deviation from the mechanical axis of the leg. If the affected joint is located between the femur and the kneecap it is called femoropatellar osteoarthritis, and usually occurs in younger people after a trauma that has damaged the cartilage, after deformation of the bone, or after an imbalance of the muscles. These two forms of osteoarthritis can occur together in 15 to 20% of cases.
Bennell KL, Paterson KL, Metcalf BR, et al. Effect of Intra-articular Platelet-Rich Plasma vs Placebo Injection on Pain and Medial Tibial Cartilage Volume in Patients With Knee Osteoarthritis: The RESTORE Randomized Clinical Trial. JAMA. 2021;326(20):2021–2030. https://doi.org/10.1001/jama.2021.19415