Table 1.

Baseline information of all included studies.

Study	Research year	Type of study	Region	Number of knees	Group	Postoperative follow-up time	Outcome measures	Results
Baumann 2016	2013–2014	Prospective cohort study	Germany	20	1. BCR	9 months	ROM	BCR implants could provide improved functional properties.
				20	2. PS
Chaudhary 2008	1999–2003	RCT	Canada	49	1. PS	3 and 24 months	ROM WOMAC RAND-36 Complication	The two treatment groups had a similar range of motion of the knee over the initial two-year postoperative period.
				51	2. CR
Harato 2008	1997–2000	RCT	Canada	99	1. CR	60 months	ROM KSS WOMAC Complication	PS design does appear to support significantly improved postoperative ROM compared with the CR design.
				93	2. PS
Scarvell 2017	2006–2010	RCT	Australia	116	1. BCS	24 months	ROM OKS KSS Complication Revision	There was no evidence of clinical superiority of one implant over the other at 2 years
				122	2. PS
Schimmel 2014	2002–2013	RCT	Netherlands	62	1. BCS	24 months	ROM KSS Complication Revision	Patients who receive a BCS system compared with those who receive a conventional PS system have comparable knee flexion characteristics and clinical and functional outcomes.
				62	2. PS
Troelsen 2019	2014–2015	RCT	Denmark	25	1. BCR	24 months	OKS FJS Revision	They found no differences between the BCR and CR implants in terms of patient-reported outcome measure scores at 2 years.
				25	2. CR
Boom 2019	2008–2011	RCT	Netherlands	59	1. CR	12 months	ROM WOMAC	There are no differences in speed of recovery of WOMAC or ROM during the first postoperative year after CR or PS TKA.
				55	2. PS
Ward 2011	2007–2010	RCT	Australia	13	1. BCS	36 months	OKS PTA	The BCS TKR produced a higher mean PTA than the PS TKR.
				15	2. PS
Tanzer 2002	2000–2010	RCT	Canada	20	1. CR	3, 6, 12 and 24 months	KSS ROM Complication	They could find no difference in the clinical, functional, or radiographic outcome of CR or PS TKAs at 2 years postoperatively.
				20	2. PS
Cho 2016	2015–2016	Prospective cohort study	Korea	51	1. CR	3 months	KSS ROM	The KSS and ROM were not significantly different between two groups.
				51	2. PS
Ozturk 2016	2007–2008	RCT	Germany	33	1. CR	1, 2, 3, 12 and 84 months	KSS ROM	PS knees gained faster and larger active flexion arc than CR knees
				28	2. PS
Christensen 2016	2013–2014	Retrospective cohort study	America	66	1. CR	12 months	ROM	BCR implant has inferior survivorship compared with a conventional CR implant.
				237	2. BCR
Baumann 2017	2013–2015	Prospective cohort study	Germany	34	1. BCR	18 months	FJS VAS EQ-5D Complication	The group of PS-TKA patients had a lower mean score value in the FJS compared to the BCR-group.
				34	2. PS
Beaupre 2016	1999–2003	RCT	Canada	32	1. CR	120 months	WOMAC RAND-36 Revision	Over 10 years postoperatively, low levels of revision or re-operation were reported in the PS and CR TKA group.
				30	2. PS
Maruyama 2004	1998–2000	RCT	Japan	20	1. CR	31.7 months	ROM KSS	There were no significant differences between the CR and PS TKAs in postoperative knee scores. However, postoperative improvement in range of motion was significantly superior in the PS group.
				20	2. PS	30.6 months
Binabdrazak 2013	2007–2008	Retrospective cohort study	Singapore	112	1. CR	24 months	ROM KSS OKS SF-36 Complication	The PS group had a significantly better final range of motion as compared to the CR group. There were no significant differences in the other outcome scores.
				83	2. PS
Carvalho 2014	2008–2009	Prospective cohort study	Brazil	14	1. CR	30.6 months	ROM	There were no differences in ROM between CR and PS TKA.
				24	2. PS
Catani 2004	NA	RCT	Sweden	20	1. CR	3, 6, 12, 24 months	ROM HSS IKS Complication	PS knee implants do not show a statistically significantly different migration of the tibial component concerning CR implants.
				20	2. PS
Chen 2014	2001–2010	Prospective cohort study	Singapore	33	1. CR	6, 24 months	KSS OKS	Although PS prostheses offer better knee flexion in TKA after the previous HTO, the knee stability, clinical scores and revision rate at 6 months and 2 years post-TKA are comparable between CR and PS prostheses.
				100	2. PS
Conditt 2004	NA	Retrospective cohort study	America	28	1. CR	12 months	KSS ROM	Substitution for the PCL may not fully restore the functional capacity of the intact PCL, particularly in high-demand activities that involve deep flexion.
				21	2. PS
Kolisek 2009	NA	Prospective cohort study	America	45	1. CR	60 months	KSS ROM	This study did not conclusively demonstrate the superiority of one knee design over the other.
				46	2. PS
Inui 2020	2012–2017	Retrospective cohort study	Japan	56	1. BCS	24 months	ROM KOOS	BCS TKA showed more normal-like kinematics and better clinical results than PS TKA.
				55	2. PS
Laidlaw 2010	NA	Retrospective cohort study	America	55	1. CR	61.2 months	ROM KSS	Passive ROM after TKA was significantly greater than pre-operative passive ROM for each cohort.
				42	2. BCR	10.5 months
				30	3. BCS	27.6 months
Lavoie 2018	2009–2013	Retrospective cohort study	Canada	100	1. BCR	6 weeks, 6, 12, 24 months	ROM KSS	Postoperative ROM was similar between BCR TKA and PS TKA when preoperative knee flexion was 130 degrees or more, and when there was no preoperative flexion contracture
				100	2. PS
Matsumoto 2012	2003–2005	RCT	Japan	25	1. CR	71.9 months 70.6 months	KSS ROM	There were no significant differences in clinical outcomes between CR and PS at the 5-year follow-up.
				25	2. PS
Moro-oka 2007	NA	Prospective cohort study	Japan	5	1. CR	72 months 70 months	KSS ROM	Preserving both cruciate ligaments in total knee arthroplasty appears to maintain some basic features of normal knee kinematics in these activities.
				9	2. BCR
Mugnai 2013	2007–2009	Retrospective cohort study	Italy	84	1. PS	30 months 29 months	ROM KOOS Complication	The bearing geometry and kinematic pattern of different guided-motion prosthetic designs can affect the clinical–functional outcome and complications type in primary TKA.
				103	2. BCS
Sando 2015	1995–2000	Prospective cohort study	Canada	143	1. CR	12.7 years	KSS WOMAC SF-12 ROM revision	PS performed better than CR in terms of clinical scores and range of motion.
				271	2. PS
Song 2020	2015–2017	Prospective cohort trial	Korea	90	1. CR	12 months	KSS WOMAC ROM	There was no notable difference in functional outcome, range of motion, kinematics, and survival rate between CR and PS TKAs.
				64	2. PS
Boom 2014	NA	Prospective cohort study	Netherlands	9	1. CR	6–9 months	KSS WOMAC ROM	The study showed no differences in kinematics and kinetics between the PS and the CR TKA design.
				12	2. PS
Vermesan 2015	NA	RCT	Italy	25	1. CR	6, 24 months	KSS ROM	Both implants had the potential to assure great outcomes.
				25	2. PS
Victor 2005	NA	RCT	America	22	1. CR	60 months	KSS WOMAC SF-36	Despite similar clinical outcomes, there are significant kinematic differences between cruciate-retaining and cruciate-substituting arthroplasties.
				22	2. PS
Yoshiya 2005	1998–2000	Prospective cohort study	Japan	20	1. CR	18–53 months	ROM	Flexion kinematics for the PS TKA was characterized by the maintenance of a constant contact position under weight-bearing conditions and posterior femoral rollback in passive flexion.
				20	2. PS

BCR: Bi-cruciate retaining; BCS: Bi-cruciate substituting; CR: Cruciate-retaining; EQ-5D: EuroQol five dimensions questionnaire; FJS: Forgotten Joint Score; HSS: Hospital for Special Surgery; HTO: High tibial osteotomy; IKS: International Knee Society; KOOS: Knee Injury and Osteoarthritis Outcome Score; KSS: Knee Society Score; NA: Not available; OKS: Oxford Knee Score; PCL: Posterior cruciate ligament; PS: Posterior-stabilized; PTA: Patellar tendon angle; RAND-36: RAND 36-Item Health Survey; RCT: Random controlled trial; ROM: Range of knee motion; SF-12: Short Form-12; SF-36: Short Form-36; TKA: Total knee arthroplasty; TKR: Total knee replacement; VAS: Visual Analogue Scale; WOMAC: Western Ontario and McMaster Universities Osteoarthritis Index.