Retention versus removal of the posterior cruciate ligament in total knee replacement: A systematic literature review within the Cochrane framework

Figures & data

Table 1.  Search strings

Dimension	Search strings
Diagnosis	Posterior cruciate ligament [MH]
	Cruciate [TW]
	PCL [TW]
	Gonarthrosis [TW]
	Osteoarthritis [TW]
	Rheuma* [TW]
	“Arthritis, Rheumatoid” [MH]
	Arthrosis [TW]
	Arthrit* [TW]
	Arthritis [MH]
Treatment	“Knee replacement” [TW]
	Arthroplasty [TW]
	Prosthesis [TW]
	Prostheses [TW]
	Endoprosthesis [TW]
	Endoprostheses [TW]
	Implant [TW]
	Prostheses and implants [MH]
	Prosthesis implantation [MH]
Study design
	RANDOMIZED-CONTROLLED TRIAL [PT]
	RANDOMIZED-CONTROLLED-TRIALS [TW]
	“Controlled Clinical Trial” [PT]
	RANDOM-ALLOCATION [TW]
	DOUBLE-BLIND-METHOD [TW]
	SINGLE-BLIND-METHOD [TW]
	CLINICAL-TRIAL [PT]
	Random* [TW]
	RESEARCH DESIGN [MH]
	“Multicentre study” [TW]
	“Multicenter study” [PT]
	“Review, Multicase” [PT]
	Trial [TW]
	“Random allocation” [MH]
	Controlled [TW]
	Prospective* [TW]
	“Prospective studies” [MH]

TW: text word; MH: mesh heading; PT: publication type

Table 2.  Methodological criteria

Checklist	Aspect	Description	Item
Van Tulder et al. (1997, 2003)	Randomization	Is a valid randomization technique applied?	A
	Allocation concealment	Was the treatment allocation concealed?	B
	Prognostic factors	Are the patient groups comparable on prognostic factors?	C
	Patient blinding	Is the patient blinded for the treatment allocation?	D
	Surgeon blinding	Is the surgeon blinded for the treatment allocation?	E
	Outcome assessor blinding	Is the outcome assessor blinded for the treatment allocation?	F
	Co-interventions	Are the co-interventions described in sufficient detail?	G
	Compliance	Is the compliance acceptable?	H
	Drop-out	Is the dropout rate given, and acceptable?	I
	Timing	Is the timing of the outcome assessments comparable between groups and consistent within groups?	J
	Intention to treat	Is an intention to treat analysis given?	K
Jadad et al. (1996)	Randomization	Was the study described as randomized?	J1
		Was the method of randomization described and appropriate?	J2
	Blinding	Was the study described as double blind?	J3
		Was the method of blinding described and appropriate?	J4
	Lost patients	Was there a description of withdrawals and dropouts?	J5

Table 3.  Characteristics of randomized controlled trials included

Study	Methods	Participants	Interventions	Outcomes
Catani et al. (2004)	RCT. Method of randomization, allocation concealment or blinding not described	Group A: 20; Group B: 20 Inclusion: Not described (OA selected) Exclusion: Not described	Brand: Optetrak, Exactech, Gainesville, FL, US PCL: Group A – retention; Group B – PS Patella: Not described Bearing: Not described Cement: Yes Flexion space: AP/ML not described	RSA KS score HSS score ROM
Clark et al. (2001)	RCT, multicentre, stratified by surgeon. Method of randomization, allocation concealment or blinding not described	Group A: 59; Group B: 69 Inclusion: Speaking English, 57–89 years of age, OA, OA plus psoriasis, or fracture OA, intact PCL Exclusion: Previous total knee arthroplasty, patellectomy, high tibial osteotomy, cruciate ligament reconstruction, knee sepsis, flexion < 90°, flexion contracture > 15°, willing to comply with the assessments, varus° 20° and valgus > 15°	Brand: AMK, DePuy / Johnson & Johnson, Warsaw Indiana, US PCL: Group A – retention; Group B – resection + PS Patella: Yes Bearing: Not described Cement: Yes Flexion space: AP – spacer blocks; ML – not described	KS score ROM SF-12 WOMAC
Maruyama et al. (2004)	RCT, bilateral procedures. Method of randomization, allocation concealment or blinding not described	Group A: 10; Group B: 10 Inclusion: Bilateral procedure, within 2 years, OA, correction of alignment can be achieved with retention of the PCL Exclusion: Significant fixed deformity	Brand: PFC from DePuy / Johnson & Johnson, Warsaw, Indiana, US PCL: Group A – retention; Group B – excision + PS Patella: Not described Bearing: Not described Cement: ? Flexion space: AP – not described; ML – posterior condylar axis	KS score Extension angle Flexion angle ROM Joint line
Misra et al. (2003)	RCT, table generated, observer blinded. Method of allocation concealment not described.	Group A: 51; Group B: 54 Inclusion: Not described (OA/RA selected) Exclusion: Not described	Brand: Press Fit Condylar (PFC), DePuy, Warsaw Indina, US PCL: Group A: Retention; Group B: Resection Patella: Criteria for resurfacing Bearing: Not described Cement: Yes Flexion space: AP/ML – not described	HSS Score ROM Satisfaction Rollback Loosening
Shoji et al. (1994)	RCT, bilateral procedures. Method of randomization, allocation concealment or blinding not described	Group A: 28; Group B: 28 Inclusion: Not described (OA/RA selected) Exclusion: Not described	Brand: Total Condylar Modifier, Biomed, Warsaw Indiana, US PCL: Group A: Retention; Group B: Resection Patella: Not described Bearing: Not described Cement: Not described Flexion space: AP/ML – not described	HSS score HSS Pain subscore HSS Muscle power subscore ROM
Strawet al. (2003)	RCT, observer blinded. Method of randomization or allocation concealment not described	Group A: 66; Group B: 101 Inclusion: Not described (OA/RA selected) Exclusion: Not described	Brand: Genesis I, Smith & Nephew PCL: Group A – retention; Group B – resection Patella: Yes Bearing: Not described Cement: Not described Flexion space: AP and ML – Monogram balancer	KS score KS score Function ROM KSS Knee pain AP stability ML stability
Swanik et al. (2004)	RCT, table generated, patient blinded. Method of allocation concealment not described.	Group A: 10; Group B: 10 Inclusion: Unilateral grade 2-3 OA Exclusion: VV > 10°, flexion contracture > 10°, peripheral neuropathy, history of cerebrovascular incidents, diabetes mellitus, RA, history of total knee arthroplasty	Brand: Nexgen, Zimmer, Warsaw, Indiana, US PCL: Group A – retention; Group B – resection + PS Patella: Not described Bearing: Not described Cement: Not described Flexion space: AP/ML– not described	Reproduction of passive positioning Threshold to detection of passive motion Balance index
Tanzer et al. (2002)	RCT, patient and observer blinded. Method of randomization or allocation concealment not described	Group A: 20; Group B: 20 Inclusion: Not described (OA, RA, avascular necrosis selected) Exclusion: Not described	Brand: Retention: Nexgen; Posterior stabilized: Legacy Zimmer, Warsaw Indiana, US PCL: Group A – retention; Group B – resection + PS Patella: Partly Bearing: Not described Cement: Yes Flexion space: AP – spacer blocks; ML – epicondylar axis	KS score Clinical KS score Functional Flexion

PCL: Posterior cruciate ligament, PS: Posterior stabilized, KS: Knee Society, HSS: Hospital Surgery, ROM: Range of motion

Table 4.  Methodological quality of randomized controlled trials found in the review

	Van Tulder Items												Jadad Items
Study	A	B	C	D	E	F	G	H	I	J	K	Total	J1	J2	J3	J4	J5	Total
Catani et al. (2004)	?	?	Yes	?	?	?	No	Yes	Yes	Yes	Yes	5	Yes	No	No	NA	Yes	2
Clark et al. (2001)	?	?	Yes	?	No	?	Yes	Yes	No	Yes	?	4	Yes	No	No	NA	No	1
Maruyama et al. (2004)	?	?	?	No	No	No	No	Yes	Yes	Yes	Yes	4	Yes	No	No	NA	No	1
Misra et al. (2003)	Yes	No	Yes	?	No	Yes	No	Yes	No	Yes	?	5	Yes	Yes	No	NA	Yes	3
Shoji et al. (1994)	?	?	?	?	No	?	No	?	Yes	No	Yes	2	Yes	No	No	NA	No	1
Straw et al. (2003)	?	?	Yes	No	No	Yes	Yes	No	No	?	?	3	Yes	No	No	NA	Yes	2
Swanik et al. (2004)	Yes	?	?	Yes	No	Yes	No	Yes	Yes	?	Yes	5	Yes	Yes	No	NA	No	2
Tanzer et al. (2002)	?	?	Yes	Yes	No	Yes	Yes	Yes	Yes	Yes	Yes	8	Yes	No	Yes	?	Yes	3

See list of items in Table 2

Figure 1. Meta-analyses of range of motion for all studies combined.

Figure 2a. Meta-analyses of range of motion for combination of studies comparing PCL retention with sacrifice in the same kind of prosthesis.

Figure 2b. Meta-analyses of range of motion for combination of studies comparing PCL retention with sacrifice and replacement with a post-and-cam mechanism.

Table 5.  Complications

Study	Complications PCR	Complications PCS/PS
Catani et al. (2004) (n = 20/20)	1 lateral release and patella resurfacing for anterior knee pain, 1 manipulation for limited ROM	2 lateral release and patella resurfacing for anterior knee pain
Maruyama et al. (2004) (n = 10/10)	None	1 superficial wound infection
Misra et al. (2003) (n = 51/54)	3 instability, 1 infection, 2 aseptic loosening, 2 stiffness	3 instability, 3 aseptic loosening, 2 stiffness, 1 reflex sympathetic dystrophy
Tanzer et al. (2002) (n = 20/20)	No revisions or migration, non-progressive radiolucencies in 3 patella, 1 tibial and 1 femoral component	No revisions or migration, non-progressive radiolucencies in 2 patella, 2 tibial and 4 femoral components

PCR: posterior cruciate retaining; PCS: posterior cruciate sacrifice; PS: posterior-stabilized.

Table 6.  Methodological aspects that need attention in the process of design and reporting of randomized controlled trials

Stage of study	Aspect	Points of attention
Design / Methods	Randomization	Describe the randomization technique used. A valid technique is applied just before the treatments are given or allocation is adequately concealed, thus ensuring unpredictable allocation.
	Allocation	Describe the measures taken to keep the treatment allocation concealed.
	concealment	Valid techniques are sealed envelopes or a telephone call to a research center for the treatment allocations.
	Selection procedure	Provide explicit selection criteria (with inclusion criteria as well as exclusion criteria).
	Treatments	Provide detailed characteristics of the treatment. In TKA, these are currently type of insert (fixed, meniscal, mobile), the status of the PCL, cementing of tibia and/or femur, coating of the implant, posterior tibial slope, and patella resurfacing.
	Outcome parameter	In studies evaluating PCL treatment in TKA, this should be flexion, stability, and contact position. When, however, more generally accepted outcome parameters are also used, the trials can be grouped together in future systematic reviews.
	Follow-up	Describe the follow-up occasions. At the very least, short-term outcome should be assessed at 1 and 2 years and long-term outcome at 5 and 10 years.
Data presentation	Acquired population	Give details of the proportion of osteoarthrosis and rheumatoid arthritis patients, deformity characteristics, age, and preoperative range of motion.
	Follow-up	Give results for the separate follow-up occasions, not only for the final follow-up.

van Tulder M W, Assendelft W J, Koes B W, Bouter L M. Method guidelines for systematic reviews in the Cochrane Collaboration Back Review Group for Spinal Disorders. Spine 1997; 22(20)2323–30

 PubMed Web of Science ®Google Scholar

van Tulder M, Furlan A, Bombardier C, Bouter L. Updated method guidelines for systematic reviews in the cochrane collaboration back review group. Spine 2003; 28(12)1290–9

 PubMed Web of Science ®Google Scholar

Jadad A R, Moore R A, Carroll D, Jenkinson C, Reynolds D J, Gavaghan D J, McQuay H J. Assessing the quality of reports of randomized clinical trials: is blinding necessary?. Control Clin Trials 1996; 17(1)1–12

 PubMedGoogle Scholar

Catani F, Leardini A, Ensini A, Cucca G, Bragonzoni L, Toksvig-Larsen S, Giannini S. The stability of the cemented tibial component of total knee arthroplasty: posterior cruciate-retaining versus posterior-stabilized design. J Arthroplasty 2004; 6(19)775–82

 Google Scholar

Clark C R, Rorabeck C H, MacDonald S, MacDonald D, Swafford J, Cleland D. Posterior-stabilized and cruciate-retaining total knee replacement: a randomized study. Clin Orthop 2001, 392: 208–12

 PubMedGoogle Scholar

Maruyama S, Yoshiya S, Matsui N, Kuroda R, Kurosaka M. Functional comparison of posterior cruciate-retaining versus posterior stabilized total knee arthroplasty. J Arthroplasty 2004; 19(3)349–53

 PubMedGoogle Scholar

Misra A N, Hussain M R, Fiddian N J, Newton G. The role of the posterior cruciate ligament in total knee replacement. J Bone Joint Surg (Br) 2003; 85(3)389–92

 PubMedGoogle Scholar

Shoji H, Wolf A, Packard S, Yoshino S. Cruciate retained and excised total knee arthroplasty. A comparative study in patients with bilateral total knee arthroplasty. Clin Orthop 1994, 305: 218–22

 PubMedGoogle Scholar

Straw R, Kulkarni S, Attfield S, Wilton T J. Posterior cruciate ligament at total knee replacement. Essential, beneficial or a hindrance? J Bone Joint Surg (Br) 2003; 85(5)671–4

 PubMedGoogle Scholar

Swanik C B, Lephart S M, Rubash H E. Proprioception, kinesthesia, and balance after total knee arthroplasty with cruciate-retaining and posterior stabilized prostheses. J Bone Joint Surg (Am) 2004; 86(2)328–34

 PubMedGoogle Scholar

Tanzer M, Smith K, Burnett S. Posterior-stabilized versus cruciate-retaining total knee arthroplasty: balancing the gap. J Arthroplasty 2002; 17(7)813–9

 PubMedGoogle Scholar