Joost Peerbooms

115 PRP in plantar fasciitis if compared to a previous study, where the same GPS and injections techniques were used, for patients with chronic lateral epicondylitis. 23 Here the authors also concluded that the corticosteroid group initially was better and then declined, whereas the PRP group progressively improved. According to Gonnade et al. 10 in their recent article, previous observational studies and a few randomized clinical trials on plantar fasciitis have concluded that PRP is an effective therapy in chronic cases, but still there is controversy due to lack of Level 1 evidence. In a single-blinded prospective randomized longitudinal case series of 40 patients, Monto 21 concluded that PRP injection is more efficacious and long-lasting than cortisone injection in the long-termmanagement of severe chronic plantar fasciitis. One trial by Shetty et al . 28 also compared PRP with cortisone, but they found no difference between the two. The drawback of Shetty et al.’s study is the short follow-up of only 3 months. The most recent study by Mahindra et al . 18 found that PRP and cortisone are better than placebo, but at 3 months of follow-up, PRP injection was significantly better than corticosteroid injection. To our knowledge, this is the first randomized that compared PRP with corticosteroids in > 100 patients with plantar fasciitis. Treatment of patients with chronic plantar fasciitis with PRP seems to reduce pain and increase function as compared with the effect of corticosteroid injection. Our findings are comparablewith other studies, but this study had a 1-year follow up. All other randomized studies had a maximum follow-up of 3 months. 10 There are some limitations of our study. First, we have to address the violation of protocol. Sixteen patients were treated with a 30-mL PRP kit instead off the 60-mL PRP kit as described in the protocol. This was due to logistic reasons and occurred in only 1 of the treating centres. Because the results suggest that the injection dosage did not affect the differences between the treatment groups in their change on the outcomes over time, we did not exclude them from this study. Our statistical analyses were also been adjusted to accommodate for this protocol violation. Furthermore, there is a large heterogeneity among different systems with regard to the concentrations of platelets, leukocytes, and growth factors in PRP. The choice for the most appropriate type of PRP should be based on the specific clinical field of application, 22 but there is no significant difference between the concentrations of PRP obtained with the GPS II (30-mL blood) and GPS III (60-mL blood). 12 Second, we did not use ultrasound-guided injections for both groups. There is always a debate about the fact that injections would not been given at the exact spot where they are needed. Ultrasound-guided technique is advocated in previous studies. 10 Kane et al. 11 showed no advantages of ultrasound guidance over direct palpation of the most tender area for guidance for the injections. A final limitation is that we have no data on the patient’s characteristics, between the study group and the 8 patients who were not suitable for further allocation. Potentially, this could lead to a bias. 7