Platelet-rich plasma (PRP) injection is a regenerative therapy generating increasing interest in sports and musculoskeletal medicine. Unlike conventional anti-inflammatory treatments, PRP aims to stimulate your body's own natural healing mechanisms. This educational guide explains what PRP is, how it works, which conditions it treats, and what results you can realistically expect.
What is Platelet-Rich Plasma (PRP)?
Platelet-rich plasma is a preparation derived from the patient's own blood. PRP contains a high concentration of platelets — blood cells that play a central role in coagulation and tissue repair — along with numerous growth factors released during platelet activation.
These growth factors (PDGF, TGF-β, VEGF, IGF, among others) can stimulate cell proliferation, promote collagen synthesis, accelerate vascularization, and modulate the inflammatory response at the injury site. PRP therefore harnesses the patient's own biological resources to promote tissue healing where natural recovery capacity is limited — such as in tendons or cartilage.
Because PRP is derived from the patient's own blood, the risk of allergic reaction or rejection is minimal. This autologous nature is one of the therapy's key advantages.
How Does PRP Treatment Work?
PRP's mechanism of action is based on the concentrated release of growth factors directly at the injury site. These signaling molecules recruit repair cells, stimulate new extracellular matrix production, and promote regeneration of damaged collagen fibers.
In tendons — whose spontaneous healing capacity is naturally limited due to poor blood supply — PRP growth factors can stimulate tenocytes (tendon cells) to produce new collagen and restore tissue architecture. In osteoarthritis, PRP can modulate the intra-articular environment and reduce certain inflammatory markers while supporting chondrocytes (cartilage cells).
It is important to understand that PRP is a regenerative therapy — its action unfolds gradually over several weeks, not in a few days like a conventional anti-inflammatory. Improvement is often gradual, and patience is part of the treatment.
Main Indications for PRP
PRP injections are used for several musculoskeletal conditions, particularly those where conventional treatments have shown limited results. The best-documented indications include:
Chronic Tendinopathies
- Lateral epicondylitis (tennis elbow) — one of the best-documented indications for PRP tendinitis treatment
- Patellar tendinopathy (jumper's knee) — patellar tendon pain in athletes
- Achilles tendinopathy — pain and thickening of the Achilles tendon
- Rotator cuff tendinopathy — for chronic cases resistant to physiotherapy
- Chronic plantar fasciitis — persistent heel pain resistant to conventional treatments
Osteoarthritis
- Knee osteoarthritis (gonarthrosis) — PRP injection knee Montreal and region; improvement in pain and joint function
- Hip osteoarthritis — as part of comprehensive management
- Small joint osteoarthritis — fingers, wrist, shoulder
Muscle and Ligament Injuries
- Partial muscle tears — to accelerate recovery in a sporting context
- Partial ligament injuries — grade II sprains with incomplete recovery
- Partial rotator cuff tears — an option to consider before surgery
To learn more about the injection services offered by Dr. Labrecque-Sauvé, visit our services page.
PRP Procedure: Step by Step
The PRP procedure takes place in several steps, generally completed in a single office visit:
- Medical consultation and evaluation — The physician confirms the clinical indication, discusses realistic expectations, and answers your questions.
- Blood draw — A venous blood sample (typically 15 to 60 mL) is drawn from your arm, just like a routine blood test.
- Centrifugation — The blood is placed in a medical centrifuge that spins at high speed for 8 to 15 minutes. This process separates blood components by density and concentrates the platelets and growth factors in the plasma fraction.
- PRP preparation — The platelet-rich fraction is collected. Platelet concentration is typically 3 to 5 times higher than in ordinary blood.
- Ultrasound-guided injection — The PRP is injected directly at the injury site under real-time ultrasound guidance for optimal precision.
- Post-procedure follow-up — Clear instructions are provided regarding permitted activities, medications to avoid, and signs to watch for.
The total procedure takes approximately 30 to 60 minutes, including consultation, blood draw, centrifugation, and injection.
Expected Results and Timeline
PRP is a biological therapy whose effects manifest progressively. Unlike cortisone, whose action can be felt within days, PRP requires more patience:
- First weeks (0-2 weeks) — A slight increase in pain may occur in the first few days — this is an expected physiological inflammatory response, indicating the growth factors are active.
- Early improvement (2-6 weeks) — Most patients begin to notice gradual improvement in pain and function.
- Optimal results (3-6 months) — Maximum benefit is generally achieved between 3 and 6 months, once tissue regeneration processes have had time to fully develop.
- Durability — Available studies suggest that the positive effects of PRP may persist 6 to 18 months, or longer for certain well-responding tendinopathies.
For chronic tendinopathies, a series of 1 to 3 injections spaced 4 to 6 weeks apart may be recommended based on clinical response. It is crucial to approach PRP with realistic expectations — results vary from patient to patient, and your physician will discuss the probability of benefit based on your specific situation.
Side Effects and Contraindications
Because PRP uses the patient's own blood, its safety profile is generally favorable. Side effects are most often mild and transient:
- Pain and tenderness at injection site — Most common. Typically lasts 2 to 5 days.
- Mild local inflammatory reaction — Moderate swelling, warmth and redness for a few days
- Bruising at blood draw site — Temporary and benign
- Infection risk — Very low with rigorous aseptic technique
Main contraindications include:
- Thrombocytopenia (low platelet count) or platelet disorders
- Severe anemia
- Active infection — local or systemic
- Active cancer or recent cancer history
- Anticoagulants — some may be temporarily suspended on medical advice
- Recent systemic corticosteroid therapy — may interfere with platelet response
Unlike cortisone, PRP contains no corticosteroids and therefore does not carry the risks associated with repeated corticosteroid injections. A complete medical evaluation is required to determine whether PRP is appropriate for your situation.
PRP vs. Cortisone vs. Viscosupplementation: Comparison
Here is an educational comparison of the three main injection options in sports medicine:
| Treatment | Mechanism | Main Indications | Onset of Action | Duration of Effect |
|---|---|---|---|---|
| PRP | Biological growth factors — stimulates tissue regeneration | Chronic tendinopathies, osteoarthritis, partial tears | 2 to 6 weeks | 6 to 18 months (variable) |
| Cortisone | Potent synthetic anti-inflammatory | Bursitis, inflammatory flare, inflammatory tendinopathy | 1 to 7 days | 1 to 6 months |
| Viscosupplementation | Joint lubrication via hyaluronic acid | Primarily knee osteoarthritis | 2 to 4 weeks | 6 to 12 months |
The choice between these approaches is based on individualized clinical judgment. To learn more, read our article on cortisone injection or visit our services page.
FAQ — Frequently Asked Questions About PRP Injection
Is PRP injection covered by insurance in Quebec?
PRP injections are not covered by the RAMQ (Quebec public health insurance). Some private insurance plans may cover part of the cost — check with your insurer. For pricing details, visit our pricing page.
How many PRP injections are typically needed?
For most tendinopathies, 1 to 3 injections spaced 4 to 6 weeks apart are considered based on clinical response. For osteoarthritis, 1 to 2 injections per year may be discussed. The optimal protocol will be determined with your physician based on your condition and individual response.
Is PRP more effective than cortisone for tendinitis?
For certain chronic tendinopathies (particularly lateral epicondylitis and patellar tendinopathy), recent scientific data suggests that PRP may offer longer-lasting benefit. Cortisone provides faster relief, but its effect may be shorter-lived for chronic tendinopathies. Your sports medicine physician will guide you to the option best suited to your specific situation.
Should I stop anti-inflammatory medications before a PRP injection?
Yes, generally. Non-steroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen can interfere with platelet response and reduce PRP efficacy. Your physician will give you precise instructions on medications to avoid in the days before and after the injection.
Can I return to sport after a PRP injection?
A relative rest period of 3 to 7 days is recommended to allow the initial inflammatory phase essential to the healing process. Progressive return to activity is then planned with your physician and, ideally, a physiotherapist. To book an appointment, use our online booking system.