There have been some important papers published in the past year comparing the benefits of injection of platelet rich plasma (PRP), hyaluronic acid (HA) and saline (placebo). These papers show statistically significant improvement in pain relief with platelet rich plasma over HA and saline. These findings offer an additional weapon in treating pain in patients with moderate osteoarthritis.
As an introduction, for decades steroids (cortisone) has been used to treat the swelling and pain of osteoarthritis. Arthritis can be mild (Grade 1-2), with softening of the cartilage that covers the end of the bone, to moderate (Grade 2-3), to severe, when the cartilage is worn down to bone (Grade 4). It has been very successful in relieving swelling and offers short term improvement in pain, but long term relief is not as predictable. It is low cost, easy to administer during an office visit, and does not require lengthy authorization and paperwork from the insurance companies. However, repetitive use of steroid injections is not healthy for the articular cartilage in the knee, and is usually restricted to at most 2-3 a year in most cases. (This is different if the patient has rheumatoid arthritis or inflammatory arthritis, which is a different problem); Many insurance companies now require a trial of a cortisone injection before use of HA.
Because of the limitations of cortisone or steroid injections, hyaluronic acid injections were developed to try to replace some of the chemical imbalance seen in the knee in osteoarthritis. The claims that HA can regrow cartilage in some of the advertising media is just not true. It acts to relieve pain in 70% of patients for up to 6-8 months in many of the series published. It is quite expensive, and requires authorization from the insurers. The patient receives one to 5 injections a week apart, but most companies have 3 injections. (There are several companies that sell HA such as Synvisc, Eufflexa, Orthovisc, or Suppartz). The risks are small, from swelling after the injection, allergic reaction to the medication, and infection.
Platelet rich plasma has been used in many areas of musculoskeletal care. The science on its benefits has been sparse, but its popularity has been widespread with the use by many famous athletes. PRP is prepared from the patients’ own blood, and involves taking a small amount of blood, and separating the platelets from the red cells and concentrating the platelets so they can be injected into the knee. This is done in the office and the injection is done at the same visit. This procedure has been done in Europe for several years, and in our office for the past 1-2 years in very select patients.
Lesley J. Anderson, MD