PRP Injection

Background and indications

Platelet-rich plasma (PRP) is an autologous product obtained by centrifugation of the patient's blood, concentrating platelets and their growth factors (PDGF, TGF-β, VEGF, IGF). Injected into a joint, tendon, or ligament, it aims to stimulate tissue healing and reduce inflammation. Image guidance (ultrasound or CT) ensures precise injection into the anatomical target.

Main indications include: moderate osteoarthritis of the knee, hip, or shoulder (as an alternative or complement to corticosteroid injections), chronic tendinopathies (lateral epicondylitis, Achilles tendinopathy, patellar tendinopathy, plantar fasciitis), partial ligament injuries, and muscle injuries.

Pre-procedure assessment

Assessment includes recent imaging (MRI or ultrasound) confirming the diagnosis and injection target, blood tests (platelet count, coagulation panel), and verification that anti-inflammatory drugs (NSAIDs) have not been taken in the preceding 5 days (NSAIDs inhibit platelet activation).

Procedure

A venous blood draw (15-30 mL) is performed, then centrifuged to isolate the platelet-rich fraction. The resulting PRP (3-6 mL) is then injected under ultrasound or CT guidance into the target (joint, tendon, enthesis). The procedure takes approximately 30 to 45 minutes. Depending on the protocol, 1 to 3 sessions spaced 2 to 4 weeks apart may be needed.

Results and scientific evidence

For knee osteoarthritis, a meta-analysis of 1,069 patients showed PRP superiority over hyaluronic acid and corticosteroids in terms of pain relief and functional improvement at 12 months (Laudy et al., British Journal of Sports Medicine, 2015; DOI: 10.1136/bjsm.2014.094036). For lateral elbow tendinopathy (tennis elbow), PRP showed superior results to corticosteroids at medium-term follow-up (Mishra et al., American Journal of Sports Medicine, 2014; DOI: 10.1177/0363546513494359).

Improvement is generally progressive over 4 to 12 weeks and may last 6 to 12 months. Results are better in moderate osteoarthritis (Kellgren-Lawrence grades II-III) than severe.

Risks and complications

As PRP is an autologous product (from the patient themselves), risks are minimal: injection site pain (common in the first 2-3 days), transient joint swelling (10-15%), puncture site bruising. Infection and allergic reaction risks are exceptional.

Recovery

Relative rest for 24-48 hours is recommended. NSAIDs should be avoided for 2 weeks after injection (they counteract the PRP effect). Gradual return to physical activities is encouraged after 1 week. Improvement is gradual and maximal at 6-12 weeks.

Practical information

The procedure is performed on an outpatient basis. It is performed by an interventional radiologist. PRP is currently not reimbursed by basic health insurance in Switzerland for most indications.