Fig. 4.

Forest plot of the included studies pooled using a random-effects model to assess long-term (≥1 year) pain relief: comparison between PRP injections and control interventions. The forest plot was acquired from meta-analyses of detailed data about differences in visual analog scale pain scores. The vertical line indicates no difference between the intervention groups. PRP: platelet-rich plasma, SD: standard deviation, IV: inverse variance, CI: confidence interval, HA: comparator hyaluronic acid, PT: physical therapy, HD: comparator hydro-dissection, HA+PRP: comparator combination of hyaluronic acid and platelet-rich plasma.