Orthobiologics

I perform many of my own ultrasound-guided injections in the office. With ultrasound, I can see the joint, tendon, bursa, or muscle on the screen and follow the needle all the way to its target. Compared with placing an injection by feel, this improves accuracy for many sports medicine procedures, particularly in deep areas like the hip.

Because I do these injections myself, the surgeon who examined you and reviewed your imaging is the same person delivering your treatment. I can also check the tissue with ultrasound at that visit, without radiation, and adjust your plan on the spot. If an injection does not give you the relief we hoped for, we already have a shared understanding of the next step, whether that is a change in therapy or a surgical discussion.

How PRP Is Made

To make PRP, I draw a small amount of your blood and spin it in a centrifuge. This separates the platelets and gathers them into a small volume of plasma. Platelets release growth factors and other signals that help direct healing and inflammation. PRP is made entirely from your own blood and contains no stem cells.

PRP is not one standard product. The number of platelets, whether white blood cells are kept or removed, how the sample is processed, and how many injections are given all vary from clinic to clinic and from study to study. That variation is one reason published results do not always line up.

Knee Arthritis

Knee arthritis has the most PRP research of any condition. In patients with mild to moderate arthritis, a number of randomized trials and pooled analyses show better pain and function scores with PRP than with hyaluronic acid (gel) injections or saline, often lasting 6 to 12 months. Leukocyte-poor PRP and higher platelet doses tend to perform best. Results are not uniform: one large placebo-controlled trial in JAMA found no benefit at 12 months. PRP helps symptoms in the right patient. It does not rebuild cartilage.

Tendon Problems

How well PRP works for a tendon depends on which tendon it is. Chronic tennis elbow has the best supporting evidence, and a randomized trial in chronic gluteal tendon pain at the side of the hip found PRP outperformed a steroid injection over two years. In contrast, a large placebo-controlled trial of chronic Achilles tendon pain showed no advantage with PRP, and studies of jumper’s knee are mixed. I use PRP for tendons together with a progressive strengthening program, never in place of one.

Muscle Strains

For acute muscle strains, especially of the hamstring, PRP has not consistently shortened recovery or lowered reinjury rates. I do not recommend it as a routine way to speed up muscle healing; a guided rehabilitation program is still the treatment that matters most. Platelet-poor plasma (PPP), the fluid left behind once platelets are separated out, is being studied for muscle injury. Early findings are encouraging, but it remains an area of active research.

What to Expect

Since PRP comes from your own blood, allergic reactions are uncommon. It is normal to feel sore, swollen, or stiff for a few days afterward, and pain can briefly worsen before it improves. Any needle carries a small risk of bleeding or infection. Most side effects reported in trials are mild and go away without treatment.

Many insurance plans do not cover PRP, so it is often paid for directly. Before scheduling, we will go over the cost, the type of PRP I use, what improvement is realistic for you, and your alternatives.

“Stem-cell injection” sounds like one treatment, but clinics use the term for many different products. These products differ in what they contain and in how the FDA regulates them, so the results of one cannot be applied to another.

• Bone marrow aspirate concentrate (BMAC): Marrow is drawn, usually from the back of the pelvis, and concentrated the same day. True stem or stromal cells make up only a tiny share of the cells, and most of the effect likely comes from the signals the cells release. The American Academy of Orthopaedic Surgeons rates the evidence for knee arthritis as limited.
• Fat-derived (adipose) products: A small amount of fat is removed with a mini-liposuction. Minimally processed fat is treated differently by the FDA than stromal vascular fraction, which is broken down with enzymes and regulated as a drug.
• Lab-grown (culture-expanded) cells: Cells are removed and multiplied in a laboratory over several weeks. The FDA classifies these as drugs, and in the United States they are available only within approved clinical trials.
• Umbilical cord, Wharton’s jelly, amniotic products, and exosomes: These come from donors. After processing, many contain few or no living cells despite being sold as stem cell treatments. The FDA has not approved any of them for an orthopedic condition and has issued public warnings about clinics that market them.

Will It Regrow My Cartilage?

This is the question I hear most, and it is where marketing goes furthest beyond the data. Some patients in cell-based studies report less pain, and a few studies show changes on MRI or in blood markers. No large trial, though, has shown that these injections restore normal cartilage or reverse arthritis. In a multicenter randomized trial published in Nature Medicine, bone marrow, fat, and umbilical cord injections did no better than a standard steroid injection for knee arthritis pain at one year. If a clinic promises you a “new knee” or guarantees you will never need surgery, be skeptical.

Whether you are considering treatment with me or elsewhere, these questions will help you judge an orthobiologic offer:

1. What exactly is being injected, and where does it come from? You should get a specific product name, not a general label like “stem cells.”
2. Has it been tested in people with my condition? Laboratory and animal studies are a starting point, not proof.
3. What has it been shown to do? Less pain, better function, faster return to sport, and regrown tissue are very different claims.
4. Is it FDA-approved for this use? A product that is “registered,” “listed,” “from a tissue bank,” or included on gov is not necessarily approved to treat anything.
5. How does it compare with my other options, including therapy, medication, standard injections, and surgery, in benefit, risk, and cost?

I am excited about where orthobiologics are headed, and PRP already has a place for selected knee arthritis and tendon problems. My goal is to offer these treatments when the evidence supports them, deliver them precisely, and be clear with you about what they can and cannot do.

Ultrasound-guided injections

1. Finnoff JT, et al. American Medical Society for Sports Medicine (AMSSM) Position Statement: Interventional Musculoskeletal Ultrasound in Sports Medicine. Br J Sports Med. 2015. PubMed
2. Daniels EW, et al. Existing Evidence on Ultrasound-Guided Injections in Sports Medicine. Orthop J Sports Med. 2018. PubMed

How PRP is made

3. Chahla J, et al. A Call for Standardization in Platelet-Rich Plasma Preparation Protocols and Composition Reporting. J Bone Joint Surg Am. 2017. PubMed

PRP for knee arthritis

4. Belk JW, et al. Platelet-Rich Plasma Versus Hyaluronic Acid for Knee Osteoarthritis: A Systematic Review and Meta-analysis of Randomized Controlled Trials. Am J Sports Med. 2021. PubMed
5. PRP Injections for the Treatment of Knee Osteoarthritis: The Improvement Is Clinically Significant and Influenced by Platelet Concentration. Am J Sports Med. 2025. PubMed
6. Bennell KL, et al. 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. PubMed
7. AAOS Technology Overview Summary: Platelet-Rich Plasma for Knee Osteoarthritis. J Am Acad Orthop Surg. 2024. PubMed

PRP for tendons and muscle

8. Fitzpatrick J, Bulsara M, Zheng MH. The Effectiveness of Platelet-Rich Plasma in the Treatment of Tendinopathy: A Meta-analysis of Randomized Controlled Clinical Trials. Am J Sports Med. 2017. PubMed
9. Platelet Concentration Explains Variability in Outcomes of Platelet-Rich Plasma for Lateral Epicondylitis. Am J Sports Med. 2025. PubMed
10. Fitzpatrick J, et al. Leucocyte-Rich Platelet-Rich Plasma Treatment of Gluteus Medius and Minimus Tendinopathy: A Double-Blind Randomized Controlled Trial With 2-Year Follow-up. Am J Sports Med. 2019. PubMed
11. Kearney RS, et al. Effect of Platelet-Rich Plasma Injection vs Sham Injection on Tendon Dysfunction in Patients With Chronic Midportion Achilles Tendinopathy. JAMA. 2021. PubMed
12. Reurink G, et al. Platelet-Rich Plasma Injections in Acute Muscle Injury. N Engl J Med. 2014. PubMed

Cell-based treatments

13. AAOS Technology Overview Summary: Concentrated Bone Marrow Aspirate for Knee Osteoarthritis. J Am Acad Orthop Surg. 2023. PubMed
14. Mautner K, et al. Cell-Based Versus Corticosteroid Injections for Knee Pain in Osteoarthritis. Nat Med. 2023. PubMed

FDA resources for patients

15. S. Food and Drug Administration. Important Patient and Consumer Information About Regenerative Medicine Therapies. FDA
16. S. Food and Drug Administration. Consumer Alert on Regenerative Medicine Products Including Stem Cells and Exosomes. FDA