TY - JOUR T1 - Platelet-rich plasma injection is not more effective than hyaluronic acid to treat knee osteoarthritis when using a random-effects model JF - British Journal of Sports Medicine JO - Br J Sports Med SP - 953 LP - 954 DO - 10.1136/bjsports-2015-095512 VL - 50 IS - 15 AU - Zhicong Wang AU - Yuehong Liu AU - Mozhen Liu Y1 - 2016/08/01 UR - http://bjsm.bmj.com/content/50/15/953.abstract N2 - In a recent meta-analysis by Laudy et al,1 the authors used a fixed-effects model when there was significant heterogeneity for Western Ontario and McMaster Universities Osteoarthritis (WOMAC) knee pain (refer to figure 11 of the article, χ2=17.12, I2=94%, p<0.0001) and WOMAC physical function (refer to figure 13 of the article, χ2=16.40, I2=94%, p<0.0001), and stated that platelet-rich plasma (PRP) reduced pain and improved function more effectively than hyaluronic acid (HA).Fixed-effects and random-effects models are the most commonly used statistical methods for meta-analysis, and systematic reviewers often need to choose one of the two models. In the presence of small heterogeneity, the fixed-effects model is more appropriate, while it inclines to the random-effects model when heterogeneity is large. Thus, dealing with heterogeneity is one of the most challenging tasks in meta-analysis.Although I2 statistics are considered good indicators for assessing heterogeneity,2 it has been found that the test has poor … ER -