Platelet-Rich-Plasma (PRP): What You Need to Know
What Is Platelet-Rich Plasma?
Platelet-rich plasma — commonly called PRP — is a regenerative medicine treatment that uses a concentrated preparation of your own blood to promote healing in damaged tissue. It is not a medication in the traditional sense. There is no drug, no foreign substance, and no synthetic compound involved. Everything injected into you comes from you.
Here is how it works. Blood is drawn from your arm — typically the same amount as a standard blood draw. That sample is placed in a centrifuge, a machine that spins the blood at high speed to separate its components by density. This process concentrates the platelets — small blood cells that play a central role in tissue repair — into a small volume of plasma. That concentrated preparation is what gets injected into the target tissue.
Platelets are best known for their role in clotting, but their function in healing goes far beyond stopping a bleed. Platelets are rich in growth factors — signaling proteins that instruct the body to recruit repair cells, stimulate new tissue formation, reduce inflammation, and promote the regeneration of cartilage, tendon, and other connective tissue. When a high concentration of these growth factors is delivered precisely to an area of damaged or degenerative tissue, the goal is to amplify and accelerate the body's own healing response.
Why Do Tendons and Joints Struggle to Heal on Their Own?
To understand why PRP can be so valuable, it helps to understand why certain tissues heal poorly in the first place.
Cartilage — the smooth cushioning tissue inside your joints — has virtually no blood supply of its own. Because healing depends on blood-borne repair cells and growth factors reaching damaged tissue, cartilage has an extremely limited capacity to repair itself once it is worn down. This is why arthritis is progressive rather than self-correcting.
Tendons are similarly challenged. While tendons do have some blood supply, it is sparse — particularly in regions that are most prone to injury and degeneration, such as the mid-portion of the Achilles tendon, the rotator cuff near its insertion on the bone, and the common extensor tendon at the lateral elbow. Chronic tendon problems — called tendinopathy — often involve areas of tendon that have undergone degenerative changes rather than true acute inflammation, meaning the normal healing cascade has essentially stalled or failed to activate meaningfully.
By delivering a high concentration of growth factors directly to these poorly vascularized tissues, PRP attempts to restart or amplify a healing response that the body has been unable to mount on its own.
How Is PRP Different From a Cortisone Shot?
This is one of the most common questions patients ask, and the distinction is important.
Corticosteroid injections — commonly called cortisone shots — work by suppressing inflammation. They are fast-acting and highly effective at reducing pain in the short term. For acute flares of inflammation, they can be an excellent tool. However, corticosteroids do not promote healing or tissue repair. In fact, there is evidence that repeated cortisone injections into tendons and joints can have a negative effect on tissue integrity over time, potentially accelerating the very degeneration they are being used to treat.
PRP takes the opposite approach. Rather than suppressing the biological environment around damaged tissue, it enriches it — delivering concentrated signals that promote cellular repair, tissue regeneration, and a more durable restoration of function. The tradeoff is that PRP typically takes longer to produce noticeable results — weeks to months rather than days — because it is working through a biological healing process rather than chemical suppression of symptoms.
For patients who are looking for a treatment that addresses the underlying problem rather than managing symptoms in the short term, PRP represents a fundamentally different strategy.
What Does the Evidence Say?
PRP has been studied extensively across a range of musculoskeletal conditions over the past two decades. The evidence is not uniform — it is stronger for some conditions than others — and it is worth being honest about where the science is robust and where more research is still needed. Here is a straightforward summary of where things stand for the most common conditions treated with PRP in a peripheral joint and soft tissue practice.
Knee Osteoarthritis: The Strongest Evidence Base
If there is one condition for which the evidence supporting PRP is overwhelming, it is knee osteoarthritis.
Multiple high-quality randomized controlled trials and several comprehensive systematic reviews and meta-analyses — the highest levels of medical evidence — have consistently shown that PRP injections for knee osteoarthritis outperform both placebo injections and hyaluronic acid (viscosupplementation) injections for reducing pain and improving function. This finding has been replicated across studies conducted in different countries, using different PRP preparation methods, and in patients with varying degrees of arthritis severity.
A 2021 systematic review and meta-analysis published in the American Journal of Sports Medicine — one of the most rigorous analyses to date — concluded that PRP provided significantly greater pain relief and functional improvement compared to hyaluronic acid and placebo at both short-term and long-term follow-up. Other landmark studies have shown benefits sustained at one and two years following injection.
The evidence is particularly strong for mild to moderate knee osteoarthritis. Patients with severe, bone-on-bone arthritis tend to show more modest responses, though many still report meaningful improvement in pain and function.
What makes knee OA such a compelling target for PRP is the biology. Articular cartilage — the smooth tissue lining the knee joint — has almost no capacity for self-repair due to its lack of blood supply. PRP delivers growth factors directly into this environment, stimulating the chondrocytes (cartilage cells) that remain to become more active, reducing the inflammatory mediators that accelerate cartilage breakdown, and improving the quality of the synovial fluid that lubricates the joint.
For patients with knee osteoarthritis who want to pursue a treatment that addresses the biology of the condition — not just the symptoms — PRP is now supported by a body of evidence strong enough that multiple major orthopedic and sports medicine societies have acknowledged it as a viable treatment option.
Shoulder Conditions: Good and Growing Evidence
The evidence for PRP in the shoulder is meaningful and continues to grow, with the strongest support coming from two common conditions: rotator cuff tendinopathy and glenohumeral (shoulder joint) osteoarthritis.
Rotator Cuff Tendinopathy and Partial Tears
The rotator cuff is a group of four tendons that stabilize and move the shoulder. Rotator cuff tendinopathy — degeneration and chronic pain within the tendon without a complete tear — is one of the most common causes of shoulder pain in active adults. Multiple randomized controlled trials have demonstrated that PRP injections into the rotator cuff produce superior long-term outcomes compared to corticosteroid injections, with the advantage of PRP becoming more apparent at three, six, and twelve months following treatment.
For partial thickness rotator cuff tears — tears that do not go all the way through the tendon — PRP has shown promising results both in terms of symptom relief and in some studies, structural improvement in tendon integrity on follow-up imaging. This is a particularly meaningful finding because it suggests PRP may be doing more than just masking symptoms — it may be promoting actual tissue repair.
Shoulder Osteoarthritis
Glenohumeral osteoarthritis — arthritis of the ball-and-socket shoulder joint — is less common than knee arthritis but can be significantly disabling. The evidence base for PRP in shoulder osteoarthritis is smaller than for the knee but is consistently positive, with studies showing meaningful improvements in pain and range of motion. For patients who are not ready for or interested in shoulder replacement surgery, PRP represents one of the more evidence-backed non-surgical options available.
Subacromial Bursitis
For subacromial bursitis — inflammation of the bursa between the rotator cuff and the overlying bone — PRP has shown comparable or superior results to corticosteroid injection in several studies, with a more durable response over time.
Hip Conditions: Good Evidence, Particularly for Osteoarthritis
The hip is a less studied target than the knee but the evidence for PRP is positive and clinically meaningful, particularly for hip osteoarthritis and greater trochanteric pain syndrome.
Hip Osteoarthritis
Several randomized controlled trials and prospective studies have demonstrated that intra-articular PRP injections for hip osteoarthritis produce significant reductions in pain and improvements in function, with results that compare favorably to corticosteroid and hyaluronic acid injections. As with the knee, benefits tend to become more apparent over time — patients often report continued improvement at three and six months following injection, in contrast to the rapid but short-lived relief seen with cortisone.
The hip joint is deeper and more technically challenging to inject accurately than the knee, which is one reason ultrasound or fluoroscopic guidance is essential for hip PRP to ensure the medication is delivered inside the joint.
Greater Trochanteric Pain Syndrome (Gluteal Tendinopathy)
Greater trochanteric pain syndrome — pain on the outer side of the hip caused by degeneration of the gluteal tendons where they attach to the bony prominence of the femur — is a condition for which PRP has shown consistently favorable outcomes in the available literature. This condition responds poorly to corticosteroid injection over the long term, and PRP's ability to target the degenerative tendon tissue directly makes it a logical and increasingly supported treatment choice.
Lateral Epicondylitis (Tennis Elbow): Strong Evidence
Tennis elbow — degeneration of the common extensor tendon where it attaches to the outer elbow — is one of the conditions with the most consistent evidence supporting PRP. Multiple randomized controlled trials have compared PRP to corticosteroid injection and to autologous whole blood injection, and PRP has consistently demonstrated superior outcomes at medium and long-term follow-up.
The pattern in these studies is notable: cortisone injections tend to outperform PRP in the first four to eight weeks — consistent with cortisone's potent short-term anti-inflammatory effect — but PRP significantly outperforms cortisone at three months, six months, and one year. This pattern reinforces the understanding that PRP is not a quick fix but a treatment that works by driving a biological healing process that takes time to fully manifest.
For patients with chronic tennis elbow that has not responded to physical therapy, activity modification, and bracing, PRP is now considered a first-line regenerative option and is supported by some of the strongest evidence in the PRP literature.
Plantar Fasciitis: Solid Supporting Evidence
Plantar fasciitis — degeneration and pain at the attachment of the plantar fascia on the heel — is another condition where PRP has performed well in clinical trials. Studies comparing PRP to corticosteroid injection have generally found that PRP produces more durable relief over six to twelve months, with cortisone providing faster initial improvement that tends to diminish over time.
For patients with chronic plantar fasciitis that has persisted beyond three to six months despite conservative measures, PRP is a well-supported next step before considering more invasive surgical options.
Achilles Tendinopathy: Promising but More Mixed
The evidence for PRP in Achilles tendinopathy is more variable than for some other conditions. Several well-designed trials have shown benefit, while others — particularly those comparing PRP to a rigorous eccentric exercise program — have shown more modest differences. The current weight of evidence suggests PRP is a reasonable option for mid-portion Achilles tendinopathy, particularly when combined with an appropriate rehabilitation program, but it may not be the slam-dunk that it is for knee osteoarthritis or lateral epicondylitis.
For insertional Achilles tendinopathy — degeneration at the point where the tendon meets the heel bone — the evidence is more limited and the technical challenge of injecting this area safely requires careful consideration of needle placement.
What Is the Treatment Process Like?
The preparation
Blood is drawn from your arm with a quantity depending on the preparation system being used. The sample is placed in a centrifuge and prepared using specific settings. The resulting PRP layer is separated and prepared for injection. The entire preparation process takes about 30 minutes and happens in the same appointment as the injection.
The injection
The injection is performed under ultrasound or fluoroscopic guidance to ensure precise placement at the target tissue. For joint injections, the PRP is delivered inside the joint space. For tendon injections, the PRP is placed at the site of degeneration or partial tearing within the tendon, often using a technique called fenestration — passing the needle through the damaged area multiple times to stimulate a local healing response alongside the growth factor delivery.
The injection itself takes only a few minutes once guidance is confirmed. Most patients describe the sensation as pressure and a familiar deep ache at the target site, which is actually a useful sign that the medication is reaching the intended tissue.
After the injection
Some increase in soreness at the injection site is common in the first few days and is considered a normal part of the inflammatory phase of healing that PRP is designed to trigger. Anti-inflammatory medications such as ibuprofen or naproxen should be avoided for one to two weeks following PRP, as they can blunt the inflammatory healing response the treatment is designed to stimulate — which is the opposite of what you want. Ice should also be avoided for similar reasons.
Activity restrictions vary depending on the target tissue. Joint injections typically require a few days of reduced activity followed by a gradual return to normal. Tendon injections may require a more structured rehabilitation protocol, as loading the tendon appropriately during the healing phase is an important part of the recovery process.
How many injections are needed?
This varies by condition and by how well you respond. For knee and hip osteoarthritis, one to three injections over a series of weeks is a common protocol. For tendon conditions, one injection followed by a rehabilitation program is often the starting point, with a second injection considered if the initial response is incomplete.
Who Is a Good Candidate for PRP?
PRP is most appropriate for patients who have a confirmed diagnosis of a condition with good supporting evidence, have tried and not achieved lasting relief with conservative treatments such as physical therapy and activity modification, are not yet at a stage that requires surgical intervention or are looking to delay surgery, and do not have contraindications such as active infection, blood disorders affecting platelet function, or certain malignancies.
It is also important to have realistic expectations. PRP is not a cure for arthritis — it does not regrow cartilage that is already gone. It works best in the earlier to moderate stages of joint degeneration, where there is still meaningful tissue to support and repair. For tendon conditions, it works best when combined with a rehabilitation program that appropriately loads the healing tissue rather than as a standalone treatment.
What About Insurance Coverage?
PRP injections are currently not covered by most commercial insurance plans or Medicare for musculoskeletal conditions. This is one of the most important practical considerations for patients considering this treatment. Despite the growing body of evidence — particularly for knee osteoarthritis — most insurers continue to classify PRP as investigational or experimental, which means the cost is typically borne by the patient out of pocket.
Costs vary by practice and geography. Your doctor's office can provide you with specific pricing information. For many patients, the cost is worth weighing against the cost of repeated cortisone injections that provide diminishing returns, the cost of ongoing pain management, and the considerably higher cost of surgical intervention down the road.
Questions to Ask Your Doctor
Is PRP appropriate for my specific diagnosis, and what does the evidence say for my condition?
How many injections are you recommending, and what is the expected timeline for seeing results?
Should I stop any medications — particularly anti-inflammatories — before and after the procedure?
Will the injection be performed under ultrasound guidance?
What rehabilitation program should I follow after the injection?
What results are realistic for someone at my stage of joint degeneration or tendon damage?
What is the cost, and are any financing options available?
If PRP does not provide adequate relief, what are the next steps?
This article is for educational purposes only and does not replace a conversation with your physician. Treatment decisions should always be made together with your care team based on your individual history, exam findings, and imaging. Specific study citations referenced in this article reflect the state of the literature at the time of writing and should not be interpreted as an endorsement of any particular PRP preparation system or protocol. If you have questions about whether PRP is right for you, please schedule a consultation.