Available online 3 January 2024

Author links open overlay panel, AbstractBackground

Total knee replacements (TKRs) are successful operations that utilities several operative techniques including cruciate retaining (CR) and posterior stabilising (PS) prostheses. To date, neither approach has proved superior. Techniques and implants are under constant evolution and new trials are published. The purpose of this meta-analysis is to determine the current risks and benefits of these two approaches so that an up-to-date clinical recommendation can be given as to which approach if any is superior.

Methods

We searched PubMed, Cochrane, Embase, Scopus, EBCSO, and Google Scholar. Risk of bias was assessed based on the Cochrane risk of bias criteria. Meta-analysisusing the random effects model was performed by the STATA software and results were displayed on forest plots. Sensitivity analysis was performed for possible causes of heterogeneity.

Results

From 1164 studies, 15 eligible trials were included. Meta-analysis showed that the CR approach had significantly lower Range of Motion and HSS scores. There was no significant difference in KSS, OKS, VAS, or WOMAC scores. Blood loss was significantly less in the CR group. However, there was no significant difference in total complications or revisions. Sensitivity analysis did not reveal any differences in the results.

Conclusion

Despite inherent limitations, this updated meta-analysis suggests that both CR and PS approaches continue to be equivocal in terms of clinical outcomes. Both patients and surgeons can be confident in selecting either approach.

Level of evidence

Level I.

Systematic review registration

the protocol of this systematic review has been registered on PROSPERO. Registration number: CRD42023391435.

Introduction

Total knee replacement (TKR) is the definitive surgical management for patients with advanced-stage knee osteoarthritis not responsive to conservative treatment. It results in very good patient outcomes. Osteoarthritis is the most common knee joint disorder, and the global prevalence is estimated to be 3.8 %.1 Total knee arthroplasty is a very common and cost-effective surgery with an 80 %–85 % patient satisfaction rate.2 Two surgical techniques exist for this operation, the posterior stabilising (PS) technique and the cruciate retaining (CR) technique. Both, the CR and PS techniques are very commonly used,3 and evidence from existing literature proves the efficacy of both methods.4

The superiority of one technique over the other remains controversial. To date, it is not yet established which of the two knee arthroplasty techniques is superior to the other in terms of clinical outcomes. More randomised controlled trials that compare the clinical outcomes between the CR and PS implant designs are being published. And not many systematic reviews examine all outcomes together. We wanted to produce an updated systematic review with new trials and include all important outcomes in one report.

This systematic review aims to compare the two common total knee arthroplasty techniques, the PS technique with the CR technique, regarding the superiority of clinical outcomes. We aim to include newly published RCTs that compare the outcomes of interest to update existing knowledge and reinforce the evidence of current literature. The distinctive characteristic of our review is that it will report five outcomes that are not usually reported together in a single review. These will be range of motion, pain, total blood loss, revision rates, and complication rates.

The population of this study is patients with end-stage knee osteoarthritis of all ages. The interventions being compared are the PS and CR techniques. The outcomes of interest in this review are divided into primary and secondary outcomes. The primary outcomes are range of motion (ROM), pain scores, and revision rates. The secondary outcomes are total blood loss (TBL) and postoperative complications.

Section snippetsMethods

The study design is a systematic review. The PRISMA checklist was used in the writing of this systematic review report.5 The study sample consists of published randomised controlled trials (RCTs).

Study selection

Figure 1 shows the number of studies retrieved by searching the databases, number of duplicates removed, number of studies screened by title and abstract, number of full text articles screened for eligibility, and the final number of studies included in our systematic review.

Study characteristics

We have presented a table showing the study's citation, publication year, number of patients, number of total knee arthroplasties, number of CR procedures and PS procedures, mean ages of the CR group and the PS group, the

Discussion

Total knee replacement is one of the most successful and effective surgical operations performed to treat end-stage knee osteoarthritis. The main findings in this meta-analysis are consistent with this statement and reveal that both TKR implant prostheses provide improvement for end-stage knee osteoarthritis patients in terms of clinical outcomes after one year of follow-up. The aim of our study was to compare the CR prosthesis with the PS prosthesis in terms of the superiority of clinical

Conclusion

This meta-analysis revealed a slight statistical advantage of the PS approach in terms of ROM, HSS score, and blood loss. However, the majority of our data revealed no difference in PROMS, total complications, or revision. The results of this updated meta-analysis are consistent with other existing analyses. Despite inherent limitations, this updated meta-analysis suggests that both PS and CR approaches continue to be equivocal in terms of clinical outcomes. Both patients and surgeons can be

Registration and protocol

This systematic review has been registered via automatic checks in the prospective register of systematic reviews (PROSPERO) under the registration number: CRD42023391435. No protocol has been registered or published elsewhere. A few amendments have been made to the protocol registration in PROSPERO. An amendment has been made to make grammatical corrections and added extra and more detailed explanations to the risk of bias section and data synthesis section as per the PRISMA-P guidelines.

Availability of data, code, and other materials

The following data are found in Figshare uploaded as documents:

Empty data extraction sheet created by the CADIMA software. https://doi.org/10.6084/m9.figshare.23497982.v1.

Populated data extraction sheet. https://doi.org/10.6084/m9.figshare.23497994.v1.

Outcome excel file used for data synthesis. https://doi.org/10.6084/m9.figshare.23497985.v1.

STATA data files. https://doi.org/10.6084/m9.figshare.23497997.v1.

STATA codes (DO-file). https://doi.org/10.6084/m9.figshare.23497988.v1.

Ethics approval and consent to participate

Not applicable.

Consent for publication

Not applicable.

Funding

Not applicable.

Authors' contributions

The corresponding author designed the systematic review protocol. All co-authors read and approved the final protocol and report.

Author declarations

All authors have no conflicts of interest to declare.

Declaration of competing interest

The authors declare that they have no competing interests.

Acknowledgements

We thank Professor Tom Fahey, the lead of the Research Methods: Protocol Development, Design & Analysis module, who has provided feedback to enhance the review protocol. The MCh programme director, Professor John O'Byrne, supervised this review. Dr. Fiona Boland from the Data Science Center (DCS) has provided statistical support.

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© 2023 Royal College of Surgeons of Edinburgh (Scottish charity number SC005317) and Royal College of Surgeons in Ireland. Published by Elsevier Ltd. All rights reserved.