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Caring Medical
Regenerative Medicine Clinics

Chicagoland office
715 Lake Street, Suite 600
Oak Park, IL 60301
708.393.8266 Phone

Southwest Florida office
9738 Commerce
Center Court
Fort Myers, FL 33908
239.303.4069 Phone

855.779.1950 Fax

Platelet Rich Plasma Therapy for Knee Osteoarthritis


In this article, Ross Hauser MD discusses the use of Platelet Rich Plasma Therapy for the treatment of knee osteoarthritis, also known as PRP Knee Injections.

A new research paper was published online on August 2, 2015 in which investigators compared the effectiveness of multiple and single platelet-rich plasma (PRP) injections as well as hyaluronic acid (HA) injections in different stages of osteoarthritis of the knee.

One hundred and sixty-two patients with different stages of knee osteoarthritis were randomly divided into four groups receiving:

  • three dose injections of platelet-rich plasma,
  • one injection of platelet-rich plasma,
  • one injection of hyaluronic acid or
  • a saline injection as a control. Please see our article on Prolotherapy that shows saline injection may not be the best control.

The test patients were separated into two groups: early osteoarthritis  and advanced osteoarthritis.

The patients were evaluated before the injection and at the 6-month follow-ups.

There was a statistically significant improvement in all the treatment groups compared with the control group.

The knee scores of patients treated with three PRP injections were significantly better than those patients of the other groups.

There was no significant difference in the scores of patients injected with one dose of PRP or hyaluronic acid.

However, there was no significant difference in the clinical results of patients with advanced osteoarthritis among the treatment groups. (Note for three shots of PRP). For an experienced Prolotherapist, PRP may be used in conjunction with other types of Prolotherapy to ensure the root of the problem is fully addressed and treated.

This research supports other research we reported on in mid July 2015 which added to the growing medical evidence for the effectiveness of Platelet Rich Plasma Therapy for knee osteoarthritis.

In this study a comparision is made between the effects of a one-time injection of PRP and corticosteroid  (cortisone shot) for the patients suffering from osteoarthritis.

Patients suffering from Grade II or Grade III  knee osteoarthritis were randomly divided into two groups: intra articular injection of PRP and cortsione.

Forty-one participants (48 knees) were involved in the research (66.7% women with and average age of 61).

Compared to the group treated with corticosteroid, PRP showed significant results for:

  • pain relief
  • being symptom free,
  • activities of daily living and quality of life

But sporting ability was not different between the 2 groups. PRP prescription was significantly more helpful for relieving patients’ pain compared to corticosteroids .It’s also notable that using PRP was more helpful in improving the 20-meter-walk test than corticosteroid treatment but none of the treatments had any impact on active flexion Range of Motion ،passive flexion Range of Motion and flexion contracture.

This study demonstrated that one shot of PRP injection, decreased joint pain more and longer-term, alleviated the symptoms, and enhanced the activity of daily living and quality of life in short-term duration in comparison with corticosteroid.2

The pitfalls of basing opinion on a single injection of Platelet Rich Plasma Therapy are many and outlined below. Fortunately in the above research, the study authors make it clear they were testing one injection of PRP vs one injection of cortisone. In other studies the entire classification of PRP can be given a positive or negative outcome based on a single injection – this of course would not be accurate as discussed below.

Some research is now moving away from trying to prove or not prove Platelet Rich Plasma Therapy is effective for knee osteoarthritis. Now research is more trying to explain how PRP works and move forward with treatment guidelines from there.

Another new study acknowledges that Platelet-rich plasma (PRP) contains high concentrations of autologous (from you) growth factors that can repair the knee. Further they found that PRP may also provide the lubrication needed to protect the cartilage. The study researchers summarized that intra-articular injections of PRP have the potential to relieve the symptoms of osteoarthritis in the knee and that there is an influence on superficial zone protein (SZP) which is a boundary lubricant in articular cartilage and plays an important role in reducing friction and wear and therefore is critical in cartilage regeneration.

Further, bovine cartilage explants (injection) were found to be influenced by PRP’s ability to stimulate natural knee lubricants. They concluded that PRP significantly stimulates cell proliferation and SZP secretion by articular cartilage and synovium of the human knee joint.3

In other words PRP is acting like hyaluronic acid, except it is healing and regenerating the knee which hyaluronic acid is not designed to do.

When treating the knee, our medical team utilizes a Comprehensive Prolotherapy injection technique which may include a combination of healing factors. PRP is commonly used in conjunction with Dextrose Prolotherapy and Stem Cell Therapy. If stem cells are used, they would be drawn from the patient and then re-injected into the knee to stimulate tissue regrowth, such as in instances of knee osteoarthritis. This is to ensure that a more thorough treatment is given to the weakened area, versus a one-shot PRP approach. Please see this article for a discussion on the general treatment of osteoarthritis including a detailed description of the PRP therapy injections and for a comparison of types of knee osetoarthritis injection therapy.

PRP and Osteoarthritis of the knee

Dextrose Prolotherapy alone has been shown to improve the quality of life in patients with knee osteoarthritis,  “suggesting that Prolotherapy may have a pain-specific disease-modifying effect.”4  With the addition of PRP the results are even more remarkable. 

The PRP affects repair of the damaged cartilage, and the Dextrose Prolotherapy strengthens the supportive structures such as the weakened ligaments and tendons that most likely led to the cartilage degeneration in the first place. The goal of this type of Comprehensive Prolotherapy treatment is to repair the entire knee.

While Platelet Rich Plasma therapy is a very promising regenerative treatment, it must be utilized by physicians who are experienced in its use. Some physicians may use PRP as a single dose treatment rather than as part of a comprehensive treatment program. Used this way PRP may not be as effective. For this reason, some researchers see the components, healing mechanisms, and outcomes of PRP as challenging, and though the treatment has repairative functions in osteoarthritis of the knee even with the single dose usage, they would like to see a standardized protocol.5

This is alluded to in another new paper which says:

“The number of publications demonstrating the therapeutic and regenerative benefits of using platelet-rich plasma as a treatment for knee osteoarthritis has been increasing in recent years. In spite of encouraging results, there are still only a few randomised control studies with strong clinical evidence, lacking clarity on points such as the optimum formulation or the mechanism of action of platelet-rich plasma. Up to this point and based on the results of clinical studies, not all patients can benefit from this therapy.”6

More than one PRP injection needed

Testing whether or not Platelet-rich plasma (PRP) provides symptomatic relief in early knee osteoarthritis in athletes, researchers looked at 78 patients with bilateral knee osteoarthritis. The patients were then divided randomly into three groups.

  • Group A (52 knees) received a single injection of PRP
  • Group B (50 knees) received 2 injections of PRP 3 weeks apart
  • Group C (46 knees) received a single injection of normal saline

The three groups were compared with each other and no improvement was noted in group C as compared with groups A and B.

The next part is interesting: there was no difference between groups A and B, which means that a single dose of PRP is as effective as two injections to alleviate symptoms in early knee osteoarthritis. The results, however, deteriorate after six months. Both groups treated with PRP had better results than did the group injected with saline only.

Other than the fact that the PRP was found effective at alleviating symptoms of osteoarthritis in the knee is the subsequent findings. Two PRP injections were no more effective than one and that the results deteriorated after six months.7

Now these findings are somewhat in agreement with other recent research that suggests a single dose of PRP worked very well for a six-month time period but the results deteriorated.8

Can PRP Prolotherapy help the patient who has already undergone knee surgery?

Yes, PRP is effective at decreasing pain and improving symptoms and quality of life in patients with chronic knee pain after surgery. Surgery entails cutting and the removal of structures. The knee joint requires these structures for cushion and stability and proper functioning. Without them, knee instability occurs. Knee ligament instability is the main cause of knee pain before and after a total knee replacement. “Instability of the knee is one of the most common causes of failure in knee arthroplasty,” because of “intraoperative injuries or excessive release of important coronal stabilizers such as the medial collateral ligament.”9 Another researcher reports, “Ligament instability is the primary reason for revision total knee arthroplasty.”10

PRP Prolotherapy strengthens the weakened ligaments and tendons that are causing instability and stabilizes the knee. PRP Prolotherapy helps the body repair the weakened structures and tissue so the knee can function optimally.

PRP Knee Injection


1. Görmeli G, Görmeli CA, Ataoglu B, Çolak C, Aslantürk O, Ertem K. Multiple PRP injections are more effective than single injections and hyaluronic acid in knees with early osteoarthritis: a randomized, double-blind, placebo-controlled trial. Knee Surg Sports Traumatol Arthrosc. 2015 Aug 2. [Epub ahead of print]

2. Forogh B, Mianehsaz E, Shoaee S, Ahadi T, Raissi GR, Sajadi S. Effect of single injection of Platelet-Rich Plasma in comparison with corticosteroid on knee osteoarthritis: a double-blind randomized clinical trial. J Sports Med Phys Fitness. 2015 Jul 14. [Epub ahead of print]

3. Sakata R, McNary SM, Miyatake K, Lee CA, Van den Bogaerde JM, Marder RA, Reddi AH. Stimulation of the Superficial Zone Protein and Lubrication in the Articular Cartilage by Human Platelet-Rich Plasma. Am J Sports Med. 2015 Mar 26. pii: 0363546515575023. [Epub ahead of print]

4.Rabago D et al. Association between disease-specific quality of life and magnetic resonance imaging outcomes in a clinical trial of prolotherapy for knee osteoarthritis. Arch Phys Med Rehabil. 2013 Nov;94(11):2075-82. doi: 10.1016/j.apmr.2013.06.025. Epub 2013 Jul 10.

5. Chang KV, Hung CY, Aliwarga F, Wang TG, Han DS, Chen WS. Comparative Effectiveness of Platelet-Rich Plasma Injections for Treating Knee Joint Cartilage Degenerative Pathology: A Systematic Review and Meta-Analysis. Arch Phys Med Rehabil. 2013 Nov 27. pii: S0003-9993(13)01212-4. doi: 10.1016/j.apmr.2013.11.006. [Epub ahead of print]

6. Simental-Mendía MA, Vílchez-Cavazos JF, Martínez-Rodríguez H. [Platelet-rich plasma in knee osteoarthritis treatment].Cir Cir. 2015 Jun 23. pii: S0009-7411(15)00100-0. doi: 10.1016/j.circir.2014.06.001. [Epub ahead of print]

7. Patel S, Dhillon MS, Aggarwal S, Marwaha N, Jain A. Treatment With Platelet-Rich Plasma Is More Effective Than Placebo for Knee Osteoarthritis: A Prospective, Double-Blind, Randomized Trial. Am J Sports Med. 2013 Jan 8. [Epub ahead of print]

8. Halpern B, Chaudhury S, Rodeo SA, Hayter C, Bogner E, Potter HG, Nguyen J. Clinical and MRI Outcomes After Platelet-Rich Plasma Treatment for Knee Osteoarthritis. Clin J Sport Med. 2012 Dec 12. [Epub ahead of print]

9. Del Gaizo DJ, Della Valle CJ. Instability in primary total knee arthroplasty. Orthopedics. 2011 Sep 9;34(9):e519-21. doi: 10.3928/01477447-20110714-46.

10. Graichen H, et al. Ligament instability in total knee arthroplasty–causal analysis. Orthopade. 2007 Jul;36(7):650, 652-6.

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