The use of platelet-rich plasma therapy in treating tennis elbow: A critical review of randomised control trials

Tennis elbow (TE) is a painful and debilitating condition of the elbow. Recently, the use of orthobiologics, such as platelet-rich-plasma (PRP), has been proposed to promote tendon regeneration. Despite their popularity, there is a paucity of updated reviews on the use of PRP compared with other treatment modalities for treating TE. The aim of this review is to summarise high quality studies that compare the use of PRP therapy with other therapies for TE and to identify areas where further research is warranted. This systematic review was performed in accordance to the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines. A comprehensive literature search of PubMed, Scopus and Cochrane Library databases was undertaken in May 2021. Articles were screened for the following criteria: randomised control trials (RCTs) involving PRP in at least one of the treatment arms for tennis elbow. The quality of the RCTs included were analysed for their risk of bias using the modified Cochrane Collaboration Risk of Bias Assessment Tool for randomised trials. A total of 20 RCTs of which 1520 TE patients were analysed. The RCTs included in this review compared PRP with various treatment modalities routinely used in clinical practice such as physiotherapy, steroid injections, Autologous Whole Blood (AWB) and surgical interventions. With regards to the quality of RCTs, collectively, selection bias was found to be low risk however, performance bias in terms of blinding of participants and personnel performed poorly. Of the 20 RCTs, only 5 studies were classified as low risk of bias. In these 5 studies, 2 RCTs compared PRP with steroids and reported contrasting results, 1 RCT compared PRP with AWB injections which reported both to be similarly efficacious, 3 RCTs included a placebo group and only 1 reported superior effects with PRP. There are 2 main types of PRP classified according to the number of pro-inflammatory leukocyte i.e. leukocyte-rich and leukocyte-poor PRP. However, only 8 studies documented the formulation of PRP used. While the heterogeneity of PRP formulations could in-part explain the reported differences in outcomes, overall there is limited robust evidence to recommend PRP therapy for TE. Further research is required to establish the optimal formulation and administration of PRP injections. Proper documentation of TE patients need to be standardised before concrete recommendations on the use of PRP therapy may be offered.