Platelet-rich plasma (PRP) is an autologous blood product containing a high concentration of platelets,
growth factors, and
cytokines, which basic science studies have shown may improve
tendinopathy. However, there is controversy over its clinical efficacy with randomized controlled trials and subsequent meta-analysis finding mixed results when treating shoulder rotator cuff
tendinopathy. The effect of leukocyte concentration on PRP has been shown to be paramount, with different concentrations being favored for different pathologies. In those with
tendinopathy, it is unclear whether leukocyte-rich or leukocyte-poor PRP is superior. Recent research shows that PRP
injections produced a significant improvement in most patients with rotator cuff
tendinopathy. However, improvement in symptoms and functional outcomes is worse in patients who have a partial-thickness
rotator cuff tear compared with isolated
tendinopathy without a partial tear. PRP may be more advantageous than
corticosteroids. Both function as
anti-inflammatories, but PRP may be potentially anabolic, whereas as
corticosteroids have a catabolic effect on tendons, which may reduce repairability if patients proceed with surgery. Additionally, there are higher
infection rates if patients ultimately go on to surgery within 3 months after
corticosteroid injections. Ultimately, we must refine the indications for best use for PRP shoulder
injections and determine the 5 R's: right patient, right
drug, right dose, right route, and right time. Finally, we must remember that patients can first try
conservative management, including
physical therapy.