Platelet rich plasma

PRP is deeived from autologous blood using a centrifugation system to facilitate growth factor released from the alpha granules found in platelets.

These growth factors modulate the intra-articular environment and potentially facilitate an anti-inflammatory, anabolic, and analgesic effect.

A platelet activator/agonist is added to activate the clotting cascade, producing a platelet gel, producing a platelet concentration of 3-5x that of native plasma.

Platelets play a fundamental role in hemostasis and are a source of growth factors.

Growth factors, stored within platelet alpha-granules, include platelet derived growth factor (PDGF), insulin like growth factor (IGF), vascular endothelial growth factor (VEGF), platelet derived angiogenic factor (PDAF), transforming growth factor beta (TGF-B), and fibroblastic growth factor.

These substances have protean anabolic properties including the capacity to remodel bone and blood vessels and promote angiogenesis, chondrogenesis, and collagen synthesis.

Collectively these processes are involved in healing following musculoskeletal injury.

The release of these growth factors is triggered by the activation of platelets.

Platelet activation can be initiated by thrombin, calcium chloride, or collagen.

Growth factors are involved in wound healing and regenerative processes including chemotaxis, proliferation, differentiation, and angiogenesis.

In addition to growth factors, platelets release numerous other substances (e.g., fibronectin, vitronectin) important in wound healing.

PRP is a fibrin framework over platelets that has the potential to support regenerative matrix.

The rationale for using PRP are to accelerate vascularization of a graft, improve soft tissue healing, reduce post operative morbidity, and enhance bone regeneration.

Advantages of using an autologous PRP include no risk of cross reactivity, immune reaction or disease transmission.

The use of PRP to enhance bone regeneration has been documented in periodontal defects,extraction sockets, during implant placement, and in guided bone regeneration procedures around implants, including sinus augmentation.

A shortened graft healing time of 50% has been demonstrated in sinus augmentation.

Studies have failed to demonstrate enhanced bone regeneration when PRP is combined with non-living graft materials.

In humans, early controlled studies demonstrated enhanced healing and bone regeneration with PRP application.

Several studies utilizing non vital grafting material have failed to show any beneficial effect.

Numerous reports have been published regarding the favorable effects of PRP on wound healing after bone augmentation.

However, many are case reports lacking

Safety of PRP remains to be an issue since increases GF in a local area may be a cancer promoting effects.

Other concern is the use of bovine thrombin in activating the PRP release to cause immunogenic reaction.

There is a paucity of critical scientific data regarding the beneficial effects of platelet rich plasma in clinical procedures.

Injections of PRP are most commonly used for disorders involving the knee and shoulder, followed by foot and ankle and lateral epicondyle.

It is thought that the disease processes noted above are most amenable to PRP are soft tissue pathology of tendons, ligaments, the labrum, and by meniscus, followed by cartilage pathology.

There are studies both purporting and refuting its adjunctive positive effect.

Among patients with symptomatic mild to moderate radiographic knee osteoarthritis, intra-articular injection of plasma rich platelets compared with injection of saline placebo, did not does not significantly result in a difference in symptoms or join structure at 12 months: not supporting the use of plasma rich platelets for the management of osteoarthritis (Bennell Kl).

Studies using PRP for lateral epicondylitis have been promising.

Platelet rich plasma  for osteoarthritis in Achilles tendinitis have been mixed.