Platelet-Rich Plasma (PRP) Therapy
Introduction
Platelet-rich plasma (PRP) is an autologous cellular therapy that falls under regenerative medicine. There has been growing interest and research in using PRP injections to treat pain and promote tissue healing for musculoskeletal conditions, as well as for skin rejuvenation, hair loss treatment, breast augmentation, and wound healing.[1][2]
PRP is prepared from the patient's own blood through centrifugation, which concentrates platelets that release growth factors. The addition of PRP to an injured site is believed to initiate tissue repair through a natural healing response, stimulating synthesis of new connective tissues and promoting revascularisation. Due to the use of autologous blood, there are limited adverse reactions compared to other injection-based therapies, such as corticosteroid injections.[1]
PRP Classifications
PRP is typically classified into three groups based on cellular composition[1]:
- Pure platelet-rich fibrin (P-PRF)
- Leukocyte-rich PRP (LR-PRP): Pro-inflammatory with high concentration of growth factors[3]
- Leukocyte-poor PRP (LP-PRP): Anti-inflammatory profile[3]
Evidence suggests that LP-PRP may be more effective than LR-PRP for certain conditions, particularly osteoarthritis, due to its anti-inflammatory properties.
Indication
Some studies have found PRP to be more beneficial in the treatment of osteoarthritis (OA) compared to saline, hyaluronic acid, or corticosteroids[2]. Tendinopathy disorders have also demonstrated good results from PRP in clinical trials, including rotator cuff disorders, gluteal tendinopathy, and lateral epicondylalgia.[2]
Achilles Tendinopathy
A 2019 meta-analysis assessed five randomised controlled trials examining the effect of PRP on Achilles tendinopathy compared to placebo treatment[4]. The only significant difference was found at 6 weeks post-treatment, with higher function in the PRP group compared to placebo. However, further follow-ups showed no significant difference between groups, suggesting benefits may be short-term only.
PRP injections for treating Knee Osteoarthritis
PRP injections are suggested to have both greater long term and short term effects on Knee OA compared to the effects of PRP and hyaluronic acid treatments in knee OA[3]. The review compared 18 randomised controlled trials and found that PRP groups demonstrated larger improvements in both short-term and long-term outcome measures compared to hyaluronic acid groups. The amount of injections and formulations used varied between trials. LP-PRP injections are recommended in some systematic reviews as the preferred type of injection[1].
Leukocyte-poor PRP formulations are emerging as the gold standard for knee osteoarthritis management, according to a 2024 systematic review of six high-quality RCTs (n=1,162 patients). The evidence is compelling: patients receiving PRP injections demonstrated significant improvements in both pain and function that remained sustained at 6-12 months post-injection, with leukocyte-poor preparations consistently outperforming other formulations.[5]
Not all evidence supports PRP for knee OA, and physiotherapists should counsel patients accordingly. A well-designed Australian RCT (n=288 patients with mild to moderate medial knee OA) found no significant advantage of PRP over saline placebo at 12 months for either symptoms or joint structure. This conflicting evidence underscores a critical clinical reality: PRP may not be a one-size-fits-all solution. Treatment decisions should be individualized based on patient-specific factors such as OA severity, previous treatment response, and functional goals rather than relying on PRP as a universal recommendation.[6]
Ankle Osteoarthritis
A randomised controlled trial conducted in the Netherlands (2018-2020) investigated the effects of intra-articular PRP injections in 100 patients with ankle osteoarthritis.[7] The study found that PRP injections, compared with placebo, did not significantly improve ankle symptoms and function over 26 weeks.
Lateral Epicondylalgia
Randomised controlled trials demonstrate better improvements in pain and function for long-term outcomes from PRP injections compared to corticosteroid injections in patients with lateral epicondylalgia.[8] PRP may be considered for patients who have failed conservative management.
Ulnar Collateral Ligament Tear
Partial and complete tears of the ulnar collateral ligament (UCL) are commonly seen in overhead throwing athletes, particularly baseball players. Case series report good functional outcomes and successful return to sport with the combination of PRP injections and structured physical therapy programs.[9]
Contraindications
Contraindications for PRP therapy include[8]:
- Immunocompromised state
- Active infection
- Inability to understand and comply with post-procedure modifications
- Coagulopathy or anticoagulation therapy
- Prosthetic joints
- Prosthetic hardware infection
- Severe cases of advanced osteoarthritis
Procedure
For the procedure, blood is collected from the patient (typically 30-60 mL) and placed into a centrifuge to separate the blood into its components. The platelet-rich portion is then extracted and injected into the targeted site, often under ultrasound or fluoroscopic guidance to ensure accurate placement.
There is currently no recognized standard for the ideal formulation of PRP. Significant heterogeneity exists regarding platelet concentration, white blood cell content, activation methods, and other growth factors in the final preparation.[2] This variability in preparation protocols contributes to inconsistent results across studies and makes direct comparisons challenging.
Post-Procedure
Post-procedure protocols vary depending on the injection location and type of injury being treated. Management may include periods of relative rest, activity modification for 1-2 weeks, and gradual progression back to function and/or sport through a structured rehabilitation program.
Post-procedure protocols have not been standardized in the available research, and practices vary by clinician and injection site. Patients are often advised to avoid taking NSAIDs in the initial post-procedure healing phase (typically 1-2 weeks) to avoid interfering with the intended pro-inflammatory healing response of PRP, though high-quality evidence for this recommendation is limited.[8]
References
- ↑ 1.0 1.1 1.2 1.3 Everts P, Onishi K, Jayaram P, Lana JF, Mautner K. Platelet-rich plasma: new performance understandings and therapeutic considerations in 2020. International journal of molecular sciences. 2020 Oct 21;21(20):7794.
- ↑ 2.0 2.1 2.2 2.3 Samadi P, Sheykhhasan M, Khoshinani HM. The use of platelet-rich plasma in aesthetic and regenerative medicine: a comprehensive review. Aesthetic plastic surgery. 2019 Jun 15;43:803-14.
- ↑ 3.0 3.1 3.2 Belk JW, Kraeutler MJ, Houck DA, Goodrich JA, Dragoo JL, McCarty EC. Platelet-rich plasma versus hyaluronic acid for knee osteoarthritis: a systematic review and meta-analysis of randomized controlled trials. The American journal of sports medicine. 2021 Jan;49(1):249-60.
- ↑ Liu CJ, Yu KL, Bai JB, Tian DH, Liu GL. Platelet-rich plasma injection for the treatment of chronic Achilles tendinopathy: a meta-analysis. Medicine. 2019 Jun;98(16).
- ↑ Nawaz H, Jawwad M, Khan M, et al. Efficacy of Platelet-Rich Plasma Injections in Knee Osteoarthritis: A Systematic Review and Meta-Analysis. Cureus. 2024 Jul 6;16(7):e63788.
- ↑ Bennell KL, Paterson KL, Metcalf BR, Duong V, Eyles J, Kasza J, Wang Y, Cicuttini F, Buchbinder R, Forbes A, Harris A. Effect of intra-articular platelet-rich plasma vs placebo injection on pain and medial tibial cartilage volume in patients with knee osteoarthritis: the RESTORE randomized clinical trial. Jama. 2021 Nov 23;326(20):2021-30.
- ↑ Paget LD, Reurink G, de Vos RJ, Weir A, Moen MH, Bierma-Zeinstra SM, Stufkens SA, Kerkhoffs GM, Tol JL, Goedegebuure S, Krips R. Effect of platelet-rich plasma injections vs placebo on ankle symptoms and function in patients with ankle osteoarthritis: a randomized clinical trial. Jama. 2021 Oct 26;326(16):1595-605.
- ↑ 8.0 8.1 8.2 Peter I, Wu K, Diaz R, Borg-Stein J. Platelet-rich plasma. Physical Medicine and Rehabilitation Clinics. 2016 Nov 1;27(4):825-53.
- ↑ Mlynarek RA, Kuhn AW, Bedi A. Platelet-rich plasma (PRP) in orthopedic sports medicine. The American journal of orthopedics. 2016 Jul;45(5):290-326.