PRP Joint Injections: How Platelet-Rich Plasma Therapy Works for Joint Pain

You've tried the cortisone shots. You've done the anti-inflammatory rounds. Maybe you even rested for weeks, hoping the knee or shoulder would just get better on its own. And it didn't.

If that sounds like your situation, you're not alone. Joint pain is one of the most common complaints we see at Med Matrix, and for many patients, conventional options have either stopped working or never addressed the actual damage. PRP joint injections offer a different approach: using your own blood to help damaged tissue repair itself, without surgery and without long-term medication.

What Is PRP (Platelet-Rich Plasma)?

PRP stands for platelet-rich plasma. Platelets are cells in your blood that contain growth factors, proteins your body uses to repair tissue, reduce swelling, and recruit healing cells to an injury site. Every time you cut your finger or twist an ankle, platelets rush to that area and start the repair process.

A PRP injection concentrates those platelets from a small sample of your own blood, then delivers them directly into a damaged joint. The goal is straightforward: put a high dose of your body's natural repair signals exactly where the damage is.

The process is simple. A small blood draw (similar to routine lab work), a spin in a centrifuge to separate and concentrate the platelets, and an injection guided by imaging into the affected joint. Start to finish, the procedure itself takes about 30 to 45 minutes.

How PRP Injections Work for Joint Pain

Platelet-rich plasma therapy works through several biological mechanisms at once. The concentrated growth factors in PRP stimulate tissue repair at the cellular level. They signal your body to send stem cells and other repair cells to the injection site, reduce inflammatory chemicals in the joint space, and promote the growth of new cartilage and connective tissue.

This is different from cortisone, which masks pain by suppressing inflammation temporarily. Cortisone doesn't rebuild anything. Repeated cortisone injections can actually weaken cartilage and tendons over time. PRP works in the opposite direction: it triggers a controlled healing response instead of shutting one down.

Most patients notice gradual improvement over 4 to 8 weeks as the tissue repair process takes hold. Some patients need a single injection. Others benefit from a series of two or three treatments spaced several weeks apart, depending on the severity of the damage.

Conditions That Respond to PRP Therapy

PRP injections are used for a range of joint and soft tissue problems. The most common conditions we treat include:

• Knee osteoarthritis. Cartilage breakdown in the knee is one of the best-studied applications for PRP. Multiple clinical trials show improvements in pain scores and joint function compared to hyaluronic acid or saline injections.
• Shoulder injuries. Rotator cuff tears (partial), frozen shoulder, and shoulder bursitis respond well to PRP, especially when surgery isn't warranted or the patient wants to avoid it.
• Hip arthritis and bursitis. PRP can reduce pain and improve mobility in hip joints affected by wear and tear or chronic bursitis.
• Tennis and golfer's elbow. Chronic tendon pain in the elbow (lateral and medial epicondylitis) is one of the earliest proven uses for PRP.
• Achilles tendinopathy. Stubborn Achilles tendon pain that hasn't responded to physical therapy or rest.
• Plantar fasciitis. Heel pain from plantar fascia damage, particularly cases that have lasted more than 6 months.

PRP is also used for arthritis in smaller joints (hands, wrists, ankles) and for ligament sprains that haven't healed fully.

What to Expect: The PRP Injection Process

Knowing what happens step by step tends to take the anxiety out of the procedure.

Before Your Appointment

You'll be asked to stop taking NSAIDs (ibuprofen, naproxen) for about 5 to 7 days before the injection. These medications interfere with platelet function, which would reduce the effectiveness of the treatment. Acetaminophen (Tylenol) is fine during this period if you need pain relief.

Stay hydrated in the days leading up to your appointment. Good hydration makes the blood draw easier and can improve platelet quality.

During the Procedure

A small blood sample is drawn from your arm, typically 30 to 60 mL (about 2 to 4 tablespoons). That sample goes into a centrifuge, which spins for about 10 to 15 minutes to separate the platelet-rich layer from red blood cells and other components.

The concentrated PRP is then injected into the affected joint using ultrasound or fluoroscopic guidance for precision. The injection itself takes only a few minutes. Some patients feel pressure or mild discomfort at the injection site, but most tolerate it well.

After the Injection

Expect some soreness and mild swelling at the injection site for 2 to 5 days. This is actually a good sign. It means the inflammatory healing cascade is starting. Ice can help with comfort, but avoid NSAIDs (they would counteract the treatment).

Most patients can return to normal daily activities within a day or two. High-impact exercise and heavy lifting should wait 2 to 4 weeks. Your provider will give you a specific timeline based on the joint treated and the severity of your condition.

PRP vs. Other Joint Treatments

Patients often ask how PRP compares to other options they've been offered. Here's a straightforward breakdown:

Cortisone injections reduce pain quickly (within days) but wear off in weeks to months. They don't promote healing and can damage cartilage with repeated use. PRP takes longer to show results but aims to actually repair tissue.

Hyaluronic acid injections (viscosupplementation) add lubrication to the joint. They can help with mild to moderate osteoarthritis. PRP goes further by stimulating the body's own repair process in addition to reducing inflammation.

Surgery (arthroscopy, joint replacement) is sometimes necessary, but many patients can delay or avoid surgery with PRP, especially for early to moderate osteoarthritis and partial tendon tears.

PRP isn't a replacement for all of these. For severe joint destruction where bone is grinding on bone, a joint replacement may still be the right call. But for mild to moderate damage, chronic tendon issues, and patients who want to preserve their joints as long as possible, PRP fills a gap that other treatments miss.

Who Is a Good Candidate for PRP?

PRP works best for patients who have mild to moderate joint damage or chronic soft tissue injuries. Good candidates typically include people with:

• Early to moderate osteoarthritis (before bone-on-bone stage)
• Chronic tendon pain that hasn't responded to physical therapy
• Partial ligament or tendon tears
• Joint pain limiting daily activities or exercise
• A desire to avoid or delay surgery

PRP may be less effective for patients with advanced joint destruction, active infections, blood disorders that affect platelet function, or certain cancers. A thorough evaluation, including imaging and lab work, helps determine whether PRP is likely to help your specific situation.

How Med Matrix Approaches PRP Therapy

PRP injections are available at plenty of clinics. What makes the approach different at a functional medicine practice is that we don't treat the joint in isolation.

Joint pain rarely exists in a vacuum. The same patient dealing with a degenerating knee may also have systemic inflammation driving cartilage breakdown, thyroid dysfunction slowing tissue repair, nutrient deficiencies limiting the raw materials the body needs to heal, or hormonal imbalances affecting muscle strength and joint stability.

Our team of 7 providers works together to look at the full picture. That starts with testing 80+ biomarkers to identify what's actually going on beneath the surface. If inflammation markers are elevated, we address that. If hormone levels are off, we address that. If the gut is compromised and nutrient absorption is poor, we address that too.

The PRP injection handles the local joint damage. The broader protocol addresses the systemic factors that caused or accelerated that damage in the first place. This combination, local repair plus whole-body optimization, tends to produce better and longer-lasting results than PRP alone.

Recovery Timeline After PRP Injections

Recovery from PRP is not instant. The treatment works by triggering a biological healing process, and that process takes time. Here's a general timeline (individual results vary):

Week 1: Mild soreness and swelling at the injection site. Rest the joint. Light walking is fine.

Weeks 2 to 4: Soreness fades. Many patients start noticing reduced pain compared to pre-injection levels. Light activity can resume.

Weeks 4 to 8: This is when most patients experience meaningful improvement. The growth factors have had time to stimulate tissue repair, and inflammation in the joint decreases.

Months 3 to 6: Continued improvement as new tissue matures and strengthens. Full benefits are typically realized by this point.

Some patients see results that last a year or more from a single treatment series. Others may benefit from periodic maintenance injections (once or twice a year) to sustain results, especially with progressive conditions like osteoarthritis.

Combining PRP with Other Therapies

PRP works well alongside other treatments. At Med Matrix, we commonly pair PRP injections with:

• Peptide therapy to support tissue repair and reduce systemic inflammation
• Anti-inflammatory nutrition protocols to create a better healing environment
• Physical therapy and targeted exercise to strengthen the muscles supporting the treated joint
• Inflammation management to address the root drivers of joint breakdown

For patients dealing with chronic fatigue or autoimmune conditions alongside joint pain, the functional medicine approach becomes even more important. These conditions share overlapping mechanisms, and treating them together produces better outcomes than treating each one separately.

Frequently Asked Questions About PRP Joint Injections

How many PRP injections will I need?

Most patients receive 1 to 3 injections spaced 4 to 6 weeks apart. The number depends on the severity of the damage, the joint being treated, and how you respond to the first injection. Some patients get significant relief from a single treatment. Others with more advanced damage benefit from a full series. Your provider will recommend a plan based on your imaging and clinical evaluation.

Is PRP therapy painful?

The injection itself causes mild to moderate discomfort, similar to a standard joint injection. Local anesthetic is used to numb the area before the PRP is delivered. Most patients describe it as pressure rather than sharp pain. The soreness after the procedure (lasting 2 to 5 days) is manageable with ice and acetaminophen.

Does insurance cover PRP injections?

Most insurance plans do not currently cover PRP therapy, as it is still considered an emerging treatment by many insurers. Med Matrix accepts HSA, FSA, CareCredit, and all major credit cards. We're upfront about costs during your consultation so there are no surprises.

How soon can I return to exercise after PRP?

Light activities like walking can resume within a day or two. Low-impact exercise (swimming, cycling) is typically fine after 1 to 2 weeks. High-impact activities, running, jumping, and heavy lifting, should wait 3 to 4 weeks minimum. Your provider will give you specific guidance based on which joint was treated and how the injection site is healing.

Take the Next Step

If joint pain is keeping you from the activities you care about, and standard treatments haven't given you lasting relief, PRP therapy is worth exploring. At Med Matrix in South Portland, Maine, we combine PRP injections with a full functional medicine evaluation to treat both the joint and the underlying factors driving your pain.

With 3,000+ patients treated and 150+ five-star reviews, our team has the experience to help you figure out whether PRP is the right fit. Get Your Free Guide + $100 Voucher and take the first step toward getting back to what you love.