Table 1.

Characteristics of the included studies

Author	Country	Patients (EM)/(IM)	Age (EM)/(IM)	Gender (EM)/(IM)	Total knee system	EM system
Jung 2013 [9]	South Korea	56/50	70.4/68.5	Female:male 6:1/5.3:1	PS prosthesis (Stryker)	Mechanical axis marker with IFD measurement
Jeon 2012 [28]	South Korea	40/40	70.1/69.2	Female	PS prosthesis (Stryker)	Markers attached to skin
Baldini 2008 [8]	Italy	50/50	71/70	Female:male 2:1/1.7:1	Posterior stabilized flex fixed-bearing prosthesis (Zimmer)	An extramedullary device with preoperative templated data
Engh 1990 [7]	USA	32/40	69.11(38-88)	Female: 53 Male: 19	Depuy	HDisc–peg taped to skin for intraoperative location

EM extramedullary group, IM intramedullary group, IFD inter-femoral head distance, ASIS anterosuperior iliac spine