TABLE 1.

Characteristics of Included Studies^a

Author (Year)	Study Design	Target Population	Treatment Duration, mo	n	Study Groups	Time Between Injections, wk	Type of PRP Used
Görmeli et al9 (2017)	Randomized, double-blind, placebo-controlled	Knee OA	6	(1) 44 (2) 39	(1) Single PRP injection (2) Triple PRP injection	(1) NA (2) 1	2A,b P4-Aαc
Uslu Güvendi et al34 (2018)	Randomized, blinded, controlled	Knee OA	6	(1) 19 (2) 14	(1) Single PRP injection (2) Triple PRP injection	(1) NA (2) 1	1B,b P3-Aαc
Kavadar et al13 (2015)	Randomized, blinded, controlled	Knee OA	6	(1) 33 (2) 32 (3) 33	(1) Single PRP injection (2) Double PRP injection (3) Triple PRP injection	(1) NA (2) 2 (3) 2	2A,b P3-x-Aαc
Patel et al24 (2013)	Randomized, double-blind, placebo-controlled	Bilateral knee OA	6	(1) 27 (2) 25	(1) Single PRP injection (2) Double PRP injection	(1) NA (2) 3	4B,b P4-x-Bβc
Simental-Mendía et al30 (2019)	Randomized, controlled	Knee OA	12	(1) 18 (2) 17	(1) Single PRP injection (2) Triple PRP injection	(1) NA (2) 2	4B,b P2-x-Bβc

^aNA, not applicable; OA, osteoarthritis; PRP, platelet-rich plasma.

^bMishra classification for PRP.²¹

^cPlatelets, activation method, and white cells classification for PRP.⁴