Data relating to Figure 4: Number of studies using either particle method or scratching the implant surfaces directly and the bearing material combinations used

		Metal-on-Polyethylene	Ceramic-on-Polyethylene	Ceramic-on-Metal	Ceramic-on-Ceramic	Metal-on-Metal	Other
Particle method	Hip	13	4	1	2	3	
	Knee	5	1				
	Pin-on-Plate/Disc	10	1				1
Scratching counterfaces directly	Hip	12	1				1
	Knee	6					2
	Pin-on-Plate/Disc	10	3				1