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Surgical Techniques

Posterior cruciate-retaining vs posterior-stabilized TKA: Understanding the similarities Cruciate-retaining and posteriorstabilizing prosthetic devices Total knee arthroplasty (TKA) has proved to be a successful technique in treating complicated knee disorders, with convincing long-term outcomes in more than 95% of the cases.1,2 The role of the posterior cruciate ligament (PCL) in TKA has been under scrutiny for several years now. The results of certain studies have suggested that retaining the damaged PCL with the use of cruciate-retaining (CR) prosthetic devices have certain native physiological advantages, such as better stability, balanced load transferring, unaltered ligament positioning, and better femoral rollback. However, certain study results have outlined the fact that relying on a damaged ligament can negatively impacted the consistency of TKAs.2,3 Though the damaged PCL may look mechanically and macroscopically normal, histologically it can be degraded.4 Hence, the use of posterior-stabilizing (PS) devices improves consistency and knee balance, and helps in maintaining the joint-line. Yet, completely substituting the PCL has been associated with excessive bone resection, tibio-femoral dislocations, wear and tear of the tibia, and patellar-chunk syndrome.3 Figure 1. Typical posterior cruciate-retaining (left) and cruciatestabilizing (right) prosthetic devices5

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Restoration of knee flexion and optimization of the range of motion (ROM) are the principal factors which influence the clinical outcomes of any particular TKA technique.6 Restoring flexion in the range of 90–95 degrees is essential for minimal routine activities such as stair climbing. However, higher ranges for 111–165 degrees would be required if sitting cross-legged or kneeling is desired.7 Other outcomes include stability, subjective patient scoring systems (eg, WOMAC, SF-36), and presence of postoperative complications.8 Both, the CR and the PS devices have shown convincing long-term results in terms of patient survival and satisfaction. Several studies have been carried out to highlight the comparative clinical outcomes of these two devices. Many of these studies showed no significant differences with the use of these two prosthetic devices, while a few favored the use of CR devices. This article focuses on arriving at an inferring comparison between the use of CR and PS prosthetic devices based on a published meta-analysis.8

PS devices superior to CR devices? Bercik et al. conducted a meta-analysis to compare data from prospective randomized clinical trials (RCTs) that compared CR and PS prosthetic devices in knee arthroplasty patients. Twelve RCTs were included into the meta-analysis for their comparison of flexion and/or ROM in CR and PS prostheses. There were 8 RCTs that reported the means and standard deviations of flexion (as shown in table 1) and 6 RCTs reported ROM (as shown in table 2), and only 2 RCTs had collectively compared both of these parameters. Data on complications related to these devices was identified and extracted from 7 RCTS. Overall, the included RCTs consisted of 1114 patients and 1265 knees.8


Surgical Techniques

Posterior cruciate-retaining vs posterior-stabilized total knee arthroplasty: Understanding the similarities

Table 1. Forest plot of the RCTs reporting knee flexion8 Study or subgroup

Cruciate retaining (CR)

Posterior stabilizing (PS)

Mean Difference

Mean

SD

Total

Mean

SD

Total

Weight

IV, Fixed, 95% CI

Chaudhary MDa

105.9

13

40

105.8

13.5

38

8.1

0.10 (-5.79, -5.99)

Harato Kb

113.7

12.8

99

117

13.5

93

20.1

-3.30 (-7.03, 0.43)

Maruyama S

122.3

15

20

131.3

13.4

20

3.6

-9.00 (-17.82, 0.18)

Snider Md

113.46

11.1

100

113.4

12.37

99

26.2

0.02 (-3.25, 3.29)

Tanzer Me

112

13

20

111

17

20

3.2

1.00 (-8.38, 10.38)

Victor J

113.3

9.9

22

114.3

9.6

22

8.4

-1.00 (-6.76, 4.76)

Wang CJg

110.7

14.89

128

112.79

11.68

96

23.1

-2.09 (-5.57, 1.39)

Yoshiya Sh

121

6

18

131

12

18

7.3

-10.00 (-16.20, -3.80)

406

100%

-2.24 (-3.91, -0.57)

c

f

Total (95% CI)

447

Heterogeneity: I =40% (p=0.11) Test of overall effect: Z=2.62 (p=0.009) 2

a b c d e f g h Total -100 -50 0 More in CR

50 100 More inPS

CI, confidence interval; SD, standard deviation. a) Chaudhary R, Beaupre LA, Johnston DW. Knee range of motion during the first two years after use of posterior cruciate-stabilizing or posterior cruciate retaining total knee prostheses. A randomized clinical trial. J Bone Joint Surg Am 2008;90:2579. (b) Harato K, et al. Midterm comparison of posterior cruciate-retaining versus -substituting total knee arthroplasty using the Genesis II prosthesis. A multicenter prospective randomized clinical trial. Knee 2008;15:217. (c) Murayama S, et al. Functional comparison of posterior cruciate-retaining versus posterior stabilized total knee arthroplasty. J Arthroplasty 2004;19:349. (d) Snider M, MacDonald S. The influence of the posterior cruciate ligament and component design on joint line position after primary total knee arthroplasty. J Arthroplasty 2009;24:1093. (e) Tanzer M, Smith K, Burnett S. Posterior-stabilized versus cruciate-retaining total knee arthroplasty: balancing the gap. J Arthroplasty 2002;17:813. (f) Victor J, Banks S, Bellemans J. Kinematics of posterior cruciate ligament-retaining and -substituting total knee arthroplasty: a prospective randomised outcome study. J Bone Joint Surg Br 2005;87:646. (g) Wang CJ, Wang JW, Chen HS. Comparing cruciate-retaining total knee arthroplasty and cruciate-substituting total knee arthroplasty: a prospective clinical study. Chang Gung Med J 2004;27:578. (h) Yoshiya S, et al. In vivo kinematic comparison of posterior cruciate-retaining and posterior stabilized total knee arthroplasties under passive and weight-bearing conditions. J Arthroplasty 2005;20:777.

Table 2. Forest plot of the RCTs reporting range of motion8 Cruciate retaining (CR)

Posterior stabilizing (PS)

Mean

SD

Total

Mean

SD

Total

Weight

IV, Fixed, 95% CI

Catalani Fa

97

15

20

114

21

20

3.0%

-17.00 (-28.31, -5.69)

Clark C

105

12

59

107

15

69

17.7%

-2.00 (-6.68, 2.68)

b

126

11.15

68

1299

10.801

68

27.7%

-3.00 (-6.74, 0.74)

c

Maruyama Sd

122.2

14.8

20

129.6

13.9

20

4.9%

-7.40 (-16.30, 1.50)

Snider Me

112.51

11.61

100

112.32 12.84

99

33.4%

0.19 (-3.21, 3.59)

100

12

66

42

13.4%

-10.00 (-15.38, -4.62)

318

100%

-3.33 (-5.30, -1.36)

Study or subgroup

b

Kim Y H

c

Straw Rf Total (95% CI)

333

110

15

Heterogeneity: I2=70% (p=0.005) Test of overall effect: Z=3.32 (p=0.009)

Mean Difference

a

d e f Total -100 -50 More in CR

0

50 100 More in PS

CI, confidence interval; SD, standard deviation. a) Catani F, et al. The stability of the cemented tibial component of total knee arthroplasty. J Arthroplasty 2004;19:775. (b) Clark CR, et al. Posterior-stabilized and cruciate-retaining total knee replacement: a randomized study. Clin Orthop Relat Res 2001;392:208. (c) Kim YH, Kim JS, Yoon SH. A recession of posterior cruciate ligament in posterior cruciate-retaining total knee arthrosplasty. J Arthroplasty 2008;23:999. (d) Murayama S, et al. Functional comparison of posterior cruciate-retaining versus posterior stabilized total knee arthroplasty. J Arthroplasty 2004;19:349. (e) Snider M, MacDonald S. The influence of the posterior cruciate ligament and component design on joint line position after primary total knee arthroplasty. J Arthroplasty 2009;24:1093. (f) Straw R, et al. Posterior cruciate ligament at total knee replacement: Essential, Beneficial or Hindrance? J Bone Joint Surg Br 2003;85:671.

Evaluation of knee flexion

Evaluation of range of motion

Since flexion is a continuous variable, results were reported in terms of mean and standard deviation. Flexion was evaluated from the data obtained from 770 patients and 853 knees. The mean difference in flexion reported between the CR and PS devices was 2.24 (95% confidence interval [CI]: 0.57–3.91) favoring the use of the PS device (p=0.009).8

ROM was evaluated from the flexion data available from 563 patients and 651 knees. ROM was also reported in terms of mean and standard deviation, as it being a continuous variable. The mean difference in flexion reported between the CR and PS devices was 3.33 (95% CI:1.36–5.30), once again favoring the PS technique (p=0.009). There was also a significant heterogeneity for this finding (I2=70%, p=0.005).8

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Surgical Techniques

Posterior cruciate-retaining versus posterior-stabilized total knee arthroplasty: Understanding the similarities

Table 3. Complications reported with the use of cruciate-retaining and posterior-stabilizing devices8 Study Tanzer et al.

Cruciate-retaining (CR) related complications a

Calani et al.b

Posterior-stabilzing (PS) related complications

No revisions

No revisions

2 lateral subluxation of patella requiring lateral release and resurfacing of patella

1 lateral subluxation of patella requiring lateral release and resurfacing of patella 1 stiff knee

Maruyama et al.c None

1 superficial infection

Wang et al.d

3 superficial wound infections 3 delayed wound healing 2 DVT 2 hematoma 2 arthrofibrosis 1 dislocation 1 posterior laxity 1 peroneal nerve impingement

2 superficial wound infections 1 hematoma 1 DVT 1 arthrofibrosis 1 posterior laxity

Victor et al.e

No revisions

No revisions

Chaudhary et al.f 1 deep infection requiring removing of hardware Harato et al.

g

7 stiff knees 5 anterior knee pain 2 postoperative hemarthrosis 1 infection (requiring a second procedure)

1 stiff knee 3 infections (requiring a second procedure) 2 anterior knee pain 1 DVT 1 stiff knee 1 postoperative hemarthrosis

DVT, deep vein thrombosis. a) Tanzer M, Smith K, Burnett S. Posterior-stabilized versus cruciate-retaining total knee arthroplasty: balancing the gap. J Arthroplasty 2002;17:813. (b) Catani F, et al. The stability of the cemented tibial component of total knee arthroplasty. J Arthroplasty 2004;19:775. (c) Murayama S, et al. Functional comparison of posterior cruciate-retaining versus posterior stabilized total knee arthroplasty. J Arthroplasty 2004;19:349. (d) Wang CJ, Wang JW, Chen HS. Comparing cruciate-retaining total knee arthroplasty and cruciate-substituting total knee arthroplasty: a prospective clinical study. Chang Gung Med J 2004;27:578. (e) Victor J, Banks S, Bellemans J. Kinematics of posterior cruciate ligament-retaining and -substituting total knee arthroplasty: a prospective randomised outcome study. J Bone Joint Surg Br 2005;87:646. (f) Chaudhary R, Beaupre LA, Johnston DW. Knee range of motion during the first two years after use of posterior cruciate-stabilizing or posterior cruciate retaining total knee prostheses. A randomized clinical trial. J Bone Joint Surg Am 2008;90:2579. (g) Harato K, et al. Midterm comparison of posterior cruciate-retaining versus -substituting total knee arthroplasty using the Genesis II prosthesis. A multicenter prospective randomized clinical trial. Knee 2008;15:217.

Technique related complications The complications reported from either of the devices are shown enlisted in Table 3. These complications were recorded on a dichotomous scale (ie, number of complications/total no. of events), but their overall effect was not significant (Z=0.90, p=0.37).8

Do patients benefit from higher flexion angles? Thomsen et al conducted a randomized double-

TKA has been proved to be a very successful reconstructive technique in treating complicated knee disorders. The role of the PCL in TKAs has been under scrutiny for many years now, with some studies favoring the use of CR devices, whilst others favoring the use of PS devices. The principal outcomes which evaluate the effectiveness of TKAs are restoration of knee flexion and ROM.

blinded, controlled trial in 33 patients, who

In the meta- analysis by Bercik et al, the inter-

underwent a bilateral TKA with a high-flex PS device

device differences reflected fairly better flexion

in one knee, and a standard CR device in the other.

and ROM with the use of PS devices. However, an

These patients were followed-up at 12 months.

increase in the flexion angle was not associated

It was observed that the flexion angles increased

with any extra patient-related benefits.

by up to 7 degrees with the use of high-flex PS

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Conclusion

devices. However, this increase did not reflect any

Since both devices have shown excellent long-term

extra advantage with regards to improved patient-

outcomes, the onus of choosing the best possible

related outcomes such as pain, better knee function,

device lies on the expertise and comfort-level of

or greater satisfaction.6

the physician with the use of a particular device.


Surgical Techniques

Posterior cruciate-retaining versus posterior-stabilized total knee arthroplasty: Understanding the similarities

References 1. 2.

3.

4.

5.

Lee JK, Choi CH. Total knee arthroplasty in rheumatoid arthritis. Knee Surg Relat Res. 2012;24(1):1–6. Ritter MA, Davis KE, Meding JB, et al. The role of the posterior cruciate ligament in total knee replacement. Bone Joint Res. 2012;1(4):64–70. Orozco F,Ong A. Posterior stabilized total knee arthroplasty, recent advances in hip and knee arthroplasty. Fokter S (Ed.). InTech, Available from: http://www.intechopen.com/books/ recent-advances-in-hip-and-knee-arthroplasty/posterior-stabilizedtotalknee-arthroplasty. Accessed on:20-11-2013. Aggarwal AK, Goel A, Radotra BD. Predictors of posterior cruciate ligament degeneration in osteoarthritic knees. J Orthop Surg (Hong Kong). 2013;21(1):15–8.

Sachinis NP. Posterior cruciate ligament retaining versus posterior cruciate ligament substituting knee arthroplasties: A four-decadesold debate. Hard Tissue. 2013.30;2(3):28.

6.

Thomsen MG, Husted H, Otte KS, et al. Do patients care about higher flexion in total knee arthroplasty? A randomized, controlled, double-blinded trial. BMC Musculoskelet Disord. 2013;14:127.

7.

Mulholland SJ, Wyss UP. Activities of daily living in non-Western cultures: Range of motion requirements for hip and knee joint implants. Int J Rehabil Res. 2001;24(3):191–8.

8.

Bercik MJ, Joshi A, Parvizi J. Posterior cruciate-retaining versus posterior-stabilized total knee arthroplasty: A meta-analysis. J Arthroplasty. 2013;28(3):439–44.

We acknowledge the contribution made to the article ‘Posterior cruciate-retaining versus posterior-stabilized total knee arthroplasty: Understanding the similarities’ by–

Dr Sanjib K Behera MS (Ortho), DNB (PMR), ISAKOSE (France), DPMR Consultant Orthopedic Surgeon, Sport Medicine Surgeon Yashoda Hospital, Secunderabad.

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Bayer surgerie issue10 dr sanjib k behera  
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