PRP and Knee Osteoarthritis

Knee Osteoarthritis Injection Choices: Platelet- Rich Plasma (PRP) versus Hyaluronic Acid 2015 Outcome:  This study suggests that PRP injection is more efficacious than gel injections in reducing symptoms of pain and improving quality of life.

Multiple PRP injections are more effective than single injections for knee osteoarthritis 2015  Outcome: The clinical results of this study suggest IA PRP and HA treatment for all stages of knee OA. For patients with early OA, multiple (3) PRP injections are useful in achieving better clinical results.

PRP Injections for the Treatment of Knee Osteoarthritis: A Meta-Analysis of Randomized Controlled Trials 2020 Outcome: The effect of platelet concentrates goes beyond its mere placebo effect, and PRP injections provide better results than other injectable options. This benefit increases over time, being not significant at earlier follow-ups but becoming clinically significant after 6 to 12 months.

The effects of repeated intra-articular PRP injections on clinical outcomes of early osteoarthritis of the knee 2014 Outcome: A series of PRP injections improved pain and function in patients with early knee OA and repeating the series at 1 year improved long term benefit.

Treatment With Platelet-Rich Plasma Is More Effective Than Placebo for Knee Osteoarthritis: A Prospective, Double-Blind, Randomized Trial 2013 Outcome: PRP injections were better than placebo for knee pain from osteoarthritis

The Short-Term Effect of PRP on Chronic Pain in Knee Osteoarthritis 2019 Outcome:  A series of 3 PRP injections results in a reduction in knee pain and an improvement in function.

Comparison between intra-articular infiltrations of placebo, steroids, hyaluronic and PRP for knee osteoarthritis: a Bayesian network meta-analysis 2020 Outcome: Injections of PRP demonstrated the best overall outcome compared to steroids, hyaluronic acid and placebo for patients with knee osteoarthrosis at 3, 6 and 12-months follow-up.

Comparing efficacy of intraarticular single cross linked Hyaluronan (HYAJOINT Plus) and platelet-rich plasma (PRP) versus PRP alone for treating knee osteoarthritis  2021 Outcome: Injection of PRP was beneficial for knee pain from osteoarthritis and combining a gel injection with it improved pain reduction

Intra-articular platelet-rich plasma (PRP) injections for treating knee pain associated with osteoarthritis of the knee in the Japanese population: a phase I and IIa clinical trial Outcome:  Injection of PRP for knee OA was beneficial for mild-moderate knee OA

Does Intra Articular Platelet Rich Plasma Injection Improve Function, Pain and Quality of Life in Patients with Osteoarthritis of the Knee? A Randomized Clinical Trial 2014 Outcome: This study showed that intra articular PRP knee injection combined with therapeutic exercise can be more effective in pain reduction and improvement of stiffness and quality of life, compared with therapeutic exercise alone.

Effect of single injection of platelet-rich plasma in comparison with corticosteroid on knee osteoarthritis: a double-blind randomized clinical trial. 2015 Outcome: Our 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 CS.

Single- and double-dose of platelet-rich plasma versus hyaluronic acid for treatment of knee osteoarthritis: A randomized controlled trial 2019 Outcome: PRP is a safe and efficient therapeutic option for treatment of knee osteoarthritis. It was demonstrated to be significantly better than hyaluronic acid. We also found that the efficacy of PRP increases after multiple injections

The effects of platelet-rich plasma injection in knee and hip osteoarthritis: a meta-analysis of randomized controlled trial 2021 Outcomes:  Intra-articular PRP injection provided better effects than other injections for OA patients, especially in knee OA patients, in terms of pain reduction and function improvement at short-term follow-up

MRI Changes After Platelet Rich Plasma Injection in Knee Osteoarthritis (Randomized Clinical Trial) 2020 Outcome: In this study, PRP improved knee pain, function and improved cartilage volume and synovial health

The influence of platelet rich plasma on synovial fluid volumes, protein concentrations, and severity of pain in patients with knee osteoarthritis 2017 Outcome:  3 PRP injections, ( 1 per month) were given and swelling in the knee decreased, and proteins associated with anti-agin increased and those associated with inflammation decreased.

Randomized controlled trial comparing hyaluronic acid, platelet-rich plasma and the combination of both in the treatment of mild and moderate osteoarthritis of the knee 2016 Outcome: The findings of the study support the use of autologous PRP as an effective treatment of mild to moderate knee osteoarthritis. It also shows that the combination of HA and PRP resulted to better outcomes than HA alone up to 1 year and PRP alone up to 3 months. Furthermore, the results suggest that combination of PRP and HA could potentially provide better functional outcomes in the first 30 days after treatment with both PRP and HA alone.

Comparison of the Clinical Effectiveness of Single Versus Multiple Injections of Platelet-Rich Plasma in the Treatment of Knee Osteoarthritis 2019 Outcome: According to our results, a single injection was as effective as multiple PRP injections in pain improvement; however, multiple injections seemed more effective in joint functionality than a single injection at 6 months. We consider that the available evidence is still insufficient, and future research on this specific topic is needed to confirm our results.

Clinical outcomes are associated with changes in ultrasonographic structural appearance after platelet‐rich plasma treatment for knee osteoarthritis 2018 Outcome: Intra‐articular injection of PRP is an effective treatment that reduced pain and improved functional status in patients with KOA. The clinical outcomes of the intra‐articular injections of PRP are associated with improved synovial hypertrophy and vascularity scores, and less effusion

Platelet-Rich Plasma Injections for Advanced Knee Osteoarthritis: A Prospective, Randomized, Double-Blinded Clinical Trial 2017 Outcome: A single PRP intra-articular injection is effective for relieving pain and improving activities of daily living and quality of life in late-stage knee OA. For patients with late-stage knee OA who are 67 years or older, 1 intra-articular injection of PRP has similar results to 1 shot of corticosteroid.

Platelet-Rich Plasma Versus Hyaluronic Acid for Knee Osteoarthritis: A Systematic Review and Meta-analysis of Randomized Controlled Trials 2021 Outcome: Patients undergoing treatment for knee OA with PRP can be expected to experience improved clinical outcomes when compared with HA. Additionally, leukocyte-poor PRP may be a superior line of treatment for knee OA over leukocyte-rich PRP, although further studies are needed that directly compare leukocyte content in PRP injections for treatment of knee OA.

The effects of platelet-rich plasma injection in knee and hip osteoarthritis: a meta-analysis of randomized controlled trials 2021 Outcome: Intra-articular PRP injection provided better effects than other injections for OA patients, especially in knee OA patients, in terms of pain reduction and function improvement at short-term follow-up

Efficacy of Platelet-Rich Plasma on Pain and Function in the Treatment of Knee Osteoarthritis: A Prospective Cohort Study 2021 Outcome: Intra-articular injections gave significant pain and flexion improvement in grades II, III and IV in OA patients, especially with multiple injection in the short-term follow-up. As a result, recommendation of repeated multiple injections up to four times is efficient in providing long time relief in knee OA.

Effect of Platelet Rich Plasma Injection Effect on Knee Osteoarthritis in Elderly: Single Dose versus Double Dose Randomized Clinical Trial 2021 Outcome: Both single and double dose injections of PRP improved pain and knee function

Does Intra-Articular Injection of Platelet-Rich Plasma Have an Effect on Cartilage Thickness in Patients with Primary Knee Osteoarthritis? 2021 Outcome: Treatment with PRP injections can reduce pain and improve knee function in patients with various degrees of articular degeneration

 Miscellaneous PRP Studies of Interest:

Comparing Intra-articular Injections of Leukocyte-Poor Platelet-Rich Plasma Versus Low–Molecular Weight Hyaluronic Acid for the Treatment of Symptomatic Osteoarthritis of the Hip: A Double-Blind, Randomized Pilot Study 2021 Outcome: Intra-articular hip injections of LP-PRP in patients with hip OA resulted in an improvement in WOMAC scores and hip internal rotation at 6 months and delayed the need for THA or a hip resurfacing procedure compared with treatment with LMW-HA.

The Effectiveness of Platelet-Rich Plasma Injections in Gluteal Tendinopathy: A Randomized, Double-Blind Controlled Trial Comparing a Single Platelet-Rich Plasma Injection With a Single Corticosteroid Injection 2018 Outcomes: Patients with chronic gluteal tendinopathy >4 months, diagnosed with both clinical and radiological examinations, achieved greater clinical improvement at 12 weeks when treated with a single PRP injection than those treated with a single corticosteroid injection

Percutaneous Tendon Fenestration Versus Platelet‐Rich Plasma Injection for Treatment of Gluteal Tendinosis 2016 Outcome: Both needle Fenestration and PRP injections resulted in 71% and 79% improvement in pain and function by 92 days

Leucocyte-Rich Platelet-Rich Plasma Treatment of Gluteus Medius and Minimus Tendinopathy: A Double-Blind Randomized Controlled Trial With 2-Year Follow-up 2019 Outcome: Pain and function improved progressively over 104 weeks in the PRP group more than the steroid group

Platelet-Rich Plasma Injections With Needle Tenotomy for Gluteus Medius Tendinopathy: A Registry Study With Prospective Follow-up 2016 Outcome: Patients with chronic moderate to severe gluteal tendinosis and partial gluteal tendon tears improved with ultrasound-guided intratendinous PRP injections

Platelet-Rich Plasma Versus Surgery for the Management of Recalcitrant Greater Trochanteric Pain Syndrome: A Systematic Review 2020 Outcome: Both PRP and surgical intervention for the treatment of recalcitrant GTPS showed statistically and clinically significant improvements based on PROs. Although not covered by most medical insurance companies, PRP injections for recalcitrant GTPS provides an effective and safe alternative after failed physical therapy.

The Effectiveness of Platelet-Rich Plasma in the Treatment of Tendinopathy: A Meta-analysis of Randomized Controlled Clinical Trials 2016 Outcomes: There is good evidence to support the use of a single injection of LR-PRP under ultrasound guidance in tendinopathy. Both the preparation and intratendinous injection technique of PRP appear to be of great clinical significance.

Outcomes After Ultrasound-Guided Platelet-Rich Plasma Injections for Chronic Tendinopathy: A Multicenter, Retrospective Review 2013  Outcome: In this retrospective study, in which we evaluated administration of PRP for chronic tendinopathy, we found that the majority of patients reported a moderate (>50%) improvement in pain symptoms.

Ultrasound-guided Platelet-rich Plasma Application Versus Corticosteroid Injections for the Treatment of Greater Trochanteric Pain Syndrome: A Prospective Controlled Randomized Comparative Clinical Study 2020 Outcome: In conclusion, patients with GTPS present better and longer-lasting clinical results when treated with US-guided PRP injections compared to those with cortisone

Ultrasound‐Guided Intratendinous Injections With Platelet‐Rich Plasma or Autologous Whole Blood for Treatment of Proximal Hamstring Tendinopathy 2015 Outcome: Both PRP and WB groups showed improvements in all outcome measures at 6 months. The PRP group showed significant improvements in 6‐month ADL and IHOT‐33 scores. The WB group reached significance in 15‐minute sitting pain. No significant between‐group differences were observed at any time point.

Platelet-rich plasma treatment improves outcomes for chronic proximal hamstring injuries in an athletic population 2014 Outcome: Six months after the injection, 10/18 patients had 80% or greater improvement in their VAS. Overall, the average improvement was 63%

Platelet-Rich Plasma in Patients With Partial-Thickness Rotator Cuff Tears or Tendinopathy Leads to Significantly Improved Short-Term Pain Relief and Function Compared With Corticosteroid Injection: A Double-Blind Randomized Controlled Trial 2021 Outcome: Patients with PTRCTs or tendinopathy experienced clinical improvement in pain and patient-reported outcome scores after both ultrasound-guided CS and PRP injections. Patients who received PRP obtained superior improvement in pain and function at short-term follow-up (3 months).

Subacromial Platelet Rich Plasma Injections Decrease Pain and Improve Functional Outcomes in Patients with Refractory Rotator Cuff Tendinopathy. 2021 Outcome: In most patients with refractory rotator cuff tendinopathy, subacromial injections of leukocyte-rich PRP significantly decreased pain, improved functional outcomes and resolved sleep disturbances. Moreover, most of the athletes returned to sports at the same level they had before the injury.

PRP and Achilles Tendonitis: Monto et al 2013 -30 patients with Chronic Achilles Tendinopathy for > 6 months received a single PRP injection. Pain and function improved significantly and 27 had healthy achilles tendons on repeat MRI.

PRP for Plantar Fasciitis:Martinelli et al 2013
-14 patients with chronic plantar fasciitis received 3 PRP injections. At 12 months follow up, patients reported their results were excellent in nine (64.3 %), good in two (14.3 %), acceptable in two (14.3 %) and poor in one (7.1 %) patient. Pain scores reduced from an average of 7 to 2.

Hip Arthritis and PRP vs PRP with Hyaluronic Acid
Results indicated that intra-articular PRP injections offer a significant clinical improvement in patients with hip OA
without relevant side effects. The benefit was significantly more stable up to 12 months as compared with the other tested treatments.
The addition of Hyaluronic Acid to PRP did not lead to a significant improvement in pain symptoms.

PRP and Knee Osteoarthritis: Sampson et al 2010
-3 Injections of PRP were given over 12 weeks. 60% of patient’s had improvement in pain and function. 50% had imaging demonstrated thickening of their knee cartilage.

PRP vs Placebo for Knee Osteoarthritis: Patel et al 2013
– 78 people with bilateral knee OA randomized to injections of saline, 1 injection of PRP or 2 injections of PRP. Those injected with PRP had significant improvements in pain, stiffness and function for at least 6 months as compared to those who received the placebo saline injection.

Knee Osteoarthritis and PRP:  Smith et al 2016
-A randomized trial where patients with mild-moderate osteoarthritis of the knees received either 3 injections of PRP or saline(salt water) over 3 weeks. Patients were followed for one year and the pain and function improved by 78% in those receiving PRP and only by 7% in those who received salt water as a placebo.

PRP vs Hyaluronic Acid Injections in Knee Osteoarthritis: Raeissadat et al 2015
-2 knee joint injections with PRP was more effective then 3 injections of hyaluronic acid (viscosupplementation)
PRP vs Hyaluronic Acid Injections in Knee Osteoarthritis: Kon et al 2011
-PRP injections showed more and longer effect than hyaluronic acid injections in reducing pain and symptoms and recovering articular function. Better results were achieved in younger and more active patients with a low degree of cartilage degeneration, whereas a worse outcome was obtained in more degenerated joints and in older patients, in whom results similar to those of viscosupplementation have been observed.

PRP and Hip Osteoarthritis: Sanchez et al 2011
-40 patients with severe hip osteoarthritis received 3 PRP injections over 3 weeks.
Patients had statistically significant reductions in pain and function questionnaires at 7 weeks and 6 months. 57.5% of patients reported a clinically relevant reduction of pain (45%, range 30–71%). 40% of these patients were classified as excellent responders who showed an early pain reduction at 6–7 weeks, which was sustained at 6 months, and a parallel reduction of disability. Side effects were negligible and were limited to a sensation of heaviness in the injection site.


Efficacy of Intra-articular Platelet-Rich Plasma Injections in Knee Osteoarthritis: A Systematic Review. Meheux CJ, et al. Arthroscopy. 2015.

Comparative effectiveness of platelet-rich plasma injections for treating knee joint cartilage degenerative pathology: a systematic review and meta-analysis. Chang KV, et al. Arch Phys Med Rehabil. 2014.

Efficacy of platelet-rich plasma injections in osteoarthritis of the knee: a systematic review and meta-analysis. Laudy AB, et al. Br J Sports Med. 2015.

Applications of Platelet-Rich Plasma in Musculoskeletal and Sports Medicine: An Evidence-Based Approach Rosalyn T Nguyen MD, Joanne Borg-Stein MD, Kelly McInnis DO.PM&R; 2011 Mar; 3(3): 226-250.

Platelet-Rich Plasma: A Milieu of Bioactive Factors Boswell SG, Cole BJ, Sundman EA, Karas V, Fortier LA
Arthroscopy 2012 Jan 25.

Musculoskeletal Applications of Platelet-Rich Plasma: Fad or Future? Kenneth S Lee, John J Wilson, David P Rabago, Geoffrey S Baer, Jon A Jacobson, Camilo G Borrero.AJR Am J Roentgenol. 2011 Mar;196(3):628-36.