Over the last several years, a lot of exciting work has done in the use of concentrated platelets taken from the patient’s own blood, and putting in joints, tendons and inflamed areas. Platelets are the cells in our blood that assist in clotting and healing tissues that have been damaged. Platelets are full of growth factors that help tissues heal.
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 in a centrifuge in a sterile manner, so they can be injected into the knee joint. 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 2-3 years in very select patients. If you have bone on bone arthritis, the usefulness of all of this options is limited.
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). Cortisone 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. Many insurance companies now require a trial of a cortisone injection before use of hyaluronic acid (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. Recent papers indicate that it’s effectiveness is not as strong as once thought.
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.
There are 4 excellent papers that have been published in the past 2-3 years that were done to the highest quality. This is called a double blind, randomized trial. This means the patients and doctors do not know whether they received the PRP or HA or saline. (Level 1).
In one study, PRP was compared to saline and the results indicated that 2 injections of PRP were not better than one, and that the PRP patients activity and pain scores in both groups were statistically better than those injected with saline. In fact, the group injected with saline (salt water) got worse over time. The results improved up to 6 months when the study ended. Other studies from Italy, have shown improvement of over a year. http://ajs.sagepub.com/content/early/2013/01/07/0363546512471299.abstract
A second study, also a Level 1 study compared PRP and HA. This study injected the knees 4 times with either HA or PRP, and compared them at 6 months. The PRP group showed a statistically significantly better outcomes than HA (p<.001). http://ajs.sagepub.com/content/40/12/2822.abstract
The other 2 studies also indicate that at 6-12 months, patients undergoing PRP injections have less pain. The level of function was not significantly different. It seems to act by restricting the rate at which enzymes in the knee break down cartilage.
It should be noted that PRP is not covered by the insurers yet, so patients would have to pay for these out of pocket. The cost varies so it is important to check out your local options and pricing.
These papers are exciting because there is finally some hard science looking at the results of several options for injections in patients with osteoarthritis. We anxiously await more Level 1 studies, so hopefully, insurers will finally recognize this as a reasonable alternative to treatment.
Risks: The risk of complications is quite low. Infection, pain after the injection, swelling may occur.
You need to not use any aspirin or blood thinning medications such as Motrin, Alleve or other anti-inflammatories for 7 days before and after the injection, since these interfere with the platelet activity. Pain relief is not as quick as a cortisone injection and can take several weeks, and continue to improve over a few months. Occasionally, a second injection is needed.
If you have any questions, please do not hesitate to contact me. I look forward to being of service to you.
Lesley J Anderson MD