This review provides an update on the current status of platelet-rich plasma (PRP). Topics covered include the current regulatory environment, economic outlook, and current clinical evidence.

The global PRP market is expected to grow to between 380 million and 4.5 billion (USD) over the next 5-10 years. The cost of a single treatment, which is not covered by most insurance, is roughly $500-$2500, with patients often returning for additional treatments. While PRP is not 'FDA-approved', it can be legally offered in the clinic 'off-label' in the USA for a myriad of musculoskeletal indications. Recently published meta-analyses have demonstrated statistically significant improvements that, in some cases, suggest that PRP may have clinically meaningful effects. However, given the fact that clearance is not synonymous with approval, PRP is a costly treatment not covered by insurance, and clinical trials have not demonstrated definitive efficacy, we recommend informing patients when providing PRP 'off-label'.

One of the suspected deleterious effects of androgenic-anabolic steroids (AAS) is the increased risk for tendon rupture. However, investigations to date have produced inconsistent results and it is still unclear how AAS influence tendons. A systematic review of the literature was conducted to identify studies that have investigated the mechanical, structural, or biologic effects that AAS have on tendons. In total, 18 highly heterogeneous studies were identified. Small animal studies made up the vast majority of published research, and contradictory results were reported frequently. All of the included studies focused on the potential deleterious effects that AAS have on tendon, which is striking given the recent use of AAS in patients following tendon injury. Rather than providing strong evidence for or against the use of AAS, this review highlights the need for additional research. Future studies investigating the use of AAS as a possible treatment for tendon injury/pathology are supported by reports suggesting that AAS may counteract the irreparable structural/functional changes that occur in the musculotendinous unit following rotator cuff tears, as well as studies suggesting that the purported deleterious effects on tendon may be transient. Other possible areas for future research are discussed in the context of key findings that may have implications for the therapeutic application of AAS. © 2018 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res.