Hyaluronic Acid (HA) was FDA approval for the treatment of osteoarthritis of the knee since the 1990’s. The major mechanisms of actions are proposed to restore the normal viscosity (thickness) of the joint fluid and the reduction of inflammatory products produced by an osteoarthritic joint. Interestingly enough, hyaluronic acid can be formed into many different shapes as a scaffold for three dimensional mesenchymal stem cell growth. The problem with hyaluronic acid treatments in the past has been the low response rate. Only 50 to 60% of the patients receiving hyaluronic injections in the knee have a positive response. This has lead some organizations such as the American Academy of Orthopedic Surgeons (AAOS) to rescind its initial recommendation of this treatment for arthritis.
Platelet Rich Plasma (PRP) has also been used in orthopedics since the 1990’s but mainly to enhance procedures using large bone grafts. Recently, this has been expanded to treat common tendon and joint problems with some success. The mechanisms of action of PRP are also numerous, but two main proposed actions include reduction of harmful biochemicals as well as the delivery of important growth factors necessary for joint hemostasis (the balance between damage and repair with each of our joints). Since, PRP is made from the host (you), it is not considered a drug and thus, does not need FDA approval. Numerous studies have been conducted comparing PRP to HA and although both provide positive benefits, PRP has been shown to have wider response in a greater number of patients over a longer period of time. Yet, there are still failures of both treatments. This led researchers to ponder the thought of combining HA with PRP to see if there is synergistic effect.
Basic research into the possibility of combining the positive benefits of restoring the natural thickness and function of the joint fluid with the growth factor benefits of platelet rich plasma led to the proposal of a three armed study comparing HA, PRP and the combination therapy of PRP and HA. In addition, a sequence of basic science studies proposed numerous positive mechanisms of action to reduce proinflammatory chemical production; protection of the cartilage and meniscus; as well as reducing the production of osteoarthritis immune cells. Thus, scientists followed these recommendations and designed a few studies on human knee osteoarthritis to see if these proposals are true.
Researchers in China have performed controlled studies examining the clinical effects of combining hyaluronic acid and platelet rich plasma for two very common orthopedic conditions, namely arthritis of the knee and partial rotator cuff tears of the shoulder. Both studies had positive results.
In the knee arthritis study, researchers conducted a double blinded, placebo controlled study over a 52 week period. This is one of the most powerful methods to determine if a treatment is equal to or superior to another treatment. Both the patients and the researchers are blinded, or unable to know which treatment each patient received. Patients either received a placebo ( a saline injection) , hyaluronic acid, PRP or a combination of PRP and hyaluronic acid injection. At the end of the study, the patients receiving the hyaluronic acid injections alone had an average increase in function and a decrease in pain by 10.9 points through a very standard method of measurement called the Western Ontario & McMaster Universities Arthritis Index abbreviated WOMAC . The PRP patients had an increase of 15.9 points, but the combination of hyaluronic acid and PRP had an amazing increase of 23.7 points! Thus, combining the two may provide superior relief for over a year period. If we compare this to some studies on knee replacement, the average improvement after a year is about 24 points. Although, this is not a direct comparison study and it is hard to compare the two results, it does give us some baseline information for future studies. 
In the shoulder study, patients were split into 4 groups of about 50 patients into each group. All the patients had a partial tear of the rotator cuff which is a common condition causing pain and weakness of the shoulder. One group received normal saline as a placebo, Group 2 received Hyaluronic Acid ( HA), Group 3 received PRP and Group 4 received the combination of PRP + HA. Again, patients were followed closely with follow up visits at 1,3,6 and 12 months and a repeat MRI. Patients were asked to complete two surveys ( the Constant Score and the American Shoulder and Elbow Surgeon). As expected, the PRP and the PRP+HA groups improved. The PRP + HA group improved the pain and function ASES score by 40.82 points and the PRP group improved by 27.02 while the HA group only improved 11.34 points and the Saline group worsened by 1.21 points. The Constant score confirmed these findings with an improvement of the PRP+HA group by 33.19 pts. The PRP group improved by 23.73 pts and the HA group by 12.93 pts. However, surprisingly the MRI scoring of the size and retraction of the rotator cuff also improved. In the combination therapy group, the score improved 5.85 pts; the PRP group also had an improvement of 2.89 pts and the HA group only improved 0.41 pt. However, the saline group worsened by 2 pts. What this data shows is that not only does the combination of HA and PRP provide far superior clinical results with reduction of pain and increased function of the shoulder, but it also demonstrates healing of the partial rotator cuff tears.
Thus, we can see a developing pattern of superior results not only in the knee, but also in the shoulder with very similar results at one year. This confirmed by patient surveys and now also by MRI evidence.
The best part of this treatment is the value for patients. A good portion of this treatment is covered by most (but not all) insurance carriers for knee arthritis. Medicare and many major carriers cover the hyaluronic acid injections and a standard PRP injection is only $500. If you have a Health Spending Account (HSA) the PRP may also be fully covered. If you have standard insurance and a HSA, you could have very good pain relief for little to no cost. There are very limited complications and side effects from these treatments, and the only drawback is the fact that you may need to have this repeated every 1-2 years. Compare this to a joint replacement costing over $35,000 and more than $4,000 out of pocket expenses as wells as a complication rate of anywhere from 3% to 16% and more than 6 weeks away from work or recreation. Most of these injections require no time off work and the complication rates are very low. Many of the current treatments for either knee arthritis or rotator cuff tears have very high costs; long periods of time away from work or physical activity and have higher rates of complications. Thus, you could argue that the combination treatment of HA and PRP is one of the best values in orthopedic medicine.
Could the combination of Hyaluronic Acid and Platelet Rich Plasma be the best idea since peanut butter combined with chocolate? As the announcer would say…”only time will tell.”
