Interview with Dr. John Kennedy chief of the division of foot and ankle surgery and professor in the department of orthopedic surgery at NYU Langone in New York City.

Here, Dr. Kennedy shares his insight into the future of platelet-rich plasma and stem cell therapy in sports medicine.

Question: How do you see platelet-rich plasma and stem cell therapy developing in sports medicine?

Dr. John Kennedy: This is a massive industry and yet there is significant divergence of opinion as to how effective these interventions are in sports medicine. Up until recently there was a paucity of good quality and level of evidence supporting these therapies. However, there is now an increasing body of evidence to support their use in augmenting and supporting regeneration and repair.

In cartilage injuries there is little or no innate potential for self-repair. Therefore, in areas like the ankle, the predominant cause for arthritic change is trauma. Up until recently, there was little we could do to alter the relentless and progressive nature of the arthritic process. Using biologic adjuncts including platelet-rich plasma and concentrated bone marrow aspirate, we can alter the biologic milieu and provide an immune modulated chondroprotective environment.

In tendon injuries we know PRP can up regulate tenocytic repair, and therefore its use has been advocated in tendon pathologies from hamstring to Achilles. While the basic science evidence for this augmented repair has been sound, it is only recently that the clinical evidence is mounting to support its use in tendon pathology. The concern is that there has been a heterogenicity of PRP being used and reported. Standardization of the intervention is impossible and therefore reported outcomes have to be examined carefully to determine the type of PRP used and what pathology it was used for.

There is significant debate at the moment as to the value of neutrophils in the PRP preparation and as to whether neutrophil deleted PRP is best in acute or chronic tendinopathies. More work will need to be done before this debate can be resolved.

While PRP has no stem cells, other therapies offer stem cells, and these may have the potential to further augment biologic repair. CBMA is a common orthopedic biologic augment. Aspirated from the iliac crest, this is concentrated and provides stem cells, growth factors and a powerful anti-inflammatory IL1RA.

CBMA was shown to be effective in improving the quality of cartilage repair in bone marrow stimulation therapies as well as improving graft integration in osteochondral autograft and allograft transplants in the ankle and knee.

It has also been shown to improve the quality of Achilles repair and speed to return to sport following CBAM augmented Achilles repair.

In all stem cell therapies, we need to be careful what we are offering our patients. Harvested stem cells may not actually be involved in the repair or regeneration of the tissue into which they are administered. Instead they may provide an immune modulation that can mediate a trophic effect on the host tissue up regulating local stem cell proliferation and repair processes.

Advances in stem cell and growth factor science has been mediated by careful and thoughtful bench research and clinical application. Unfortunately, there is a tendency for many clinicians — and indeed industry — to expand the indications of these useful therapies beyond their capability to affect a positive effect. When we have a hammer, everything looks like a nail and so there is concern that these therapies are being used in an unregulated fashion. This is seen in the emergence of regeneration centers in many metropolitan areas. This is a concerning development as the majority of these are unregulated without university, state or federal oversight, and are advertising treatment and cures that are simply beyond the scope of what we currently can substantiate with scientific evidence. It is incumbent upon the orthopedic community to know more about biologics before we recommend them so we can gather data in a scientific fashion that will help further their indications as well as determine areas in which they have no role.  

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