PRP and orthobiologics: the better-studied end of the field

The definition

Platelet-rich plasma is made by drawing your own blood, spinning it to concentrate the platelets, and injecting that concentrate into an injured tendon, ligament or joint. Platelets carry growth factors, and the working hypothesis is that concentrating them at an injury site supports the body's own repair response.

Orthobiologics is the broader umbrella term that also covers bone marrow aspirate concentrate and similar same-day autologous preparations.

Where the material comes from

From you, on the day, in the same visit. Nothing is cultured, banked or donor-derived. That single fact is why the regulatory and logistical picture is so much simpler than for cell therapies, and why randomised trials have been easier to run.

Studied uses versus marketed uses

PRP has accumulated a substantial body of human research in knee osteoarthritis, tendinopathies such as tennis elbow and patellar tendinopathy, and some rotator cuff and plantar fascia conditions. Johns Hopkins describes it as used for chronic tendon injuries, acute injuries and after surgery, while noting that its use is still being studied and that results vary.

It is also marketed for hair loss, skin rejuvenation and sexual function. Those uses have much thinner support than the musculoskeletal ones, and should not inherit the credibility of the tendon and joint literature.

Evidence and regulatory reality

The comparison problem is the defining feature of this literature. Platelet concentration, whether white cells are included, the volume injected, the number of injections, whether imaging guided the needle and what rehabilitation followed all differ between studies. Pooled analyses therefore combine treatments that are not really the same treatment.

PRP is often handled under same-day autologous procedure rules rather than as a manufactured medicine, which is why availability is broad. Broad availability is not the same as established benefit for a given indication.

Questions worth asking a provider

• Which preparation system is used, and what platelet concentration does it produce?
• Is the preparation leukocyte-rich or leukocyte-poor, and why that choice for my condition?
• How many injections are planned, and over what interval?
• Will the injection be image-guided?
• What rehabilitation programme goes with it, and who supervises that?
• What outcome measure will we use, and when do we decide whether it worked?