Table 4.

Literature review of knee flexion and component loosening in high-flexion design knees

Study	Prosthesis	Implant type	Mean followup (years)	Loosening	Mean flexion (°)	Number of knees
Cho et al. [8]	NexGen® LPS-Flex	PS	4.2	30	131	218
Choi et al. [9]	P.F.C.® Sigma® RP-F	Rotating platform	2.3	0	128	85
Endres and Wilke [13]	NexGen® CR-Flex	CR	5	0	122	75
Han et al. [16]	NexGen® LPS-Flex	PS	2.7	27	129	72
Kim et al. [19]	NexGen® CR-Flex NexGen® LPS-Flex	CR PS	2.3/2.3	0/0	133/135	85/85
Lee et al. [21]	NexGen® LPS-Flex	PS	2		131	41
Current study	NexGen® CR-Flex NexGen® LPS-Flex	CR PS	6.2/6/0	0/0	135/134	47/42

PS = PCL substituting; CR = PCL retaining.