Meta-Analysis
Copyright ©The Author(s) 2021. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Clin Cases. Jan 16, 2021; 9(2): 357-371
Published online Jan 16, 2021. doi: 10.12998/wjcc.v9.i2.357
Limb length discrepancy after total knee arthroplasty: A systematic review and meta-analysis
Sujit Kumar Tripathy, Siddharth Satyakam Pradhan, Paulson Varghese, Prabhudev Prasad Purudappa, Sandeep Velagada, Tarun Goyal, Bijnya Birajita Panda, Jagadeesh Vanyambadi
Sujit Kumar Tripathy, Siddharth Satyakam Pradhan, Paulson Varghese, Sandeep Velagada, Department of Orthopaedics, All India Institute of Medical Sciences, Bhubaneswar 751019, Odisha, India
Prabhudev Prasad Purudappa, Department of Orthopedics, VA Boston Health care, Boston, Massachusetts 02130, United States
Tarun Goyal, Department of Orthopaedics, All India Institute of Medical Sciences, Bathinda 209201, India
Bijnya Birajita Panda, Department of Ophthalmology, SCB Medical College, Cuttack 751019, India
Jagadeesh Vanyambadi, Department of Orthopaedics, Salford Royal NHS Foundation Trust, Salford M6 8HD, United Kingdom
Author contributions: Tripathy SK, Pradhan SS, Varghese P and Panda BB designed the study, searched the literature and screened the articles; the assessment of the quality of the studies and the statistical analysis was performed by Tripathy SK, Panda BB, Vanyambadi J and Goyal T; Velagada S, Purudappa PP and Tripathy SK wrote the manuscript; Tripathy SK, Purudappa PP and Goyal T provided intellectual content; all authors read the manuscript and approved the final manuscript for publication.
Conflict-of-interest statement: On behalf of all authors, the corresponding author states that there is no conflict of interest.
PRISMA 2009 Checklist statement: The authors have read the PRISMA 2009 Checklist, and the manuscript was prepared and revised according to the PRISMA 2009 Checklist.
Open-Access: This article is an open-access article that was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution NonCommercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/Licenses/by-nc/4.0/
Corresponding author: Sujit Kumar Tripathy, DNB, MBBS, MD, Additional Professor, Department of Orthopaedics, All India Institute of Medical Sciences, Sijua, Patrapada, Bhubaneswar 751019, Odisha, India. sujitortho@yahoo.co.in
Received: September 16, 2020
Peer-review started: September 16, 2020
First decision: November 14, 2020
Revised: November 14, 2020
Accepted: December 11, 2020
Article in press: December 11, 2020
Published online: January 16, 2021
Processing time: 113 Days and 18.7 Hours
Abstract
BACKGROUND

Limb length discrepancy (LLD) after total knee arthroplasty (TKA) has been considered as one of the reasons for the unsatisfactory outcome. However, there is no consensus about the extent of LLD that can be considered as clinically relevant.

AIM

To evaluate the incidence of radiographic LLD and its impact on functional outcome following TKA.

METHODS

All randomized-controlled trial and observational studies on LLD in TKA, published till 22nd June 2020, were systematically searched and reviewed. The primary outcome was “limb lengthening or LLD after TKA”. The secondary outcomes included “assessment of LLD in varus/valgus deformity” and “impact of LLD on the functional outcome”.

RESULTS

Of 45 retrieved studies, qualitative and quantitative assessment of data was performed from eight studies and six studies, respectively. Five studies (n = 1551) reported the average limb lengthening of 5.98 mm. The LLD after TKA was ranging from 0.4 ± 10 mm to 15.3 ± 2.88 mm. The incidence of postoperative radiographic LLD was reported in 44% to 83.3% of patients. There was no difference in the preoperative and postoperative LLD (MD -1.23; 95%CI: -3.72, 1.27; P = 0.34). Pooled data of two studies (n = 219) revealed significant limb lengthening in valgus deformity than varus (MD -2.69; 95%CI: -5.11, 0.27; P = 0.03). The pooled data of three studies (n = 611) showed significantly worse functional outcome in patients with LLD of ≥ 10 mm compared to < 10 mm (standard MD 0.58; 95%CI: 0.06, 1.10; P = 0.03).

CONCLUSION

Limb lengthening after TKA is common, and it is significantly more in valgus than varus deformity. Significant LLD (≥ 10 mm) is associated with suboptimal functional outcome.

Keywords: Arthroplasty; Knee; Replacement; Limb length; Joint diseases; Surgery

Core Tip: Limb length inequality following total knee arthroplasty (TKA) is an important cause of patient dissatisfaction. This meta-analysis evaluated the limb length discrepancy (LLD) and its impact on the functional outcome following TKA. Five studies (n = 1551) reported the average limb lengthening of 5.98 mm. The LLD after TKA was ranging from 0.4 ± 10 mm to 15.3 ± 2.88 mm. There was no difference in the preoperative and postoperative LLD (MD -1.23; 95%CI: -3.72, 1.27; P = 0.34). Pooled data of two studies (n = 219) revealed significant limb lengthening in valgus deformity than varus (MD -2.69; 95%CI: -5.11, 0.27; P = 0.03). The pooled data of three studies (n = 611) showed significantly worse functional outcome in patients with LLD of ≥ 10 mm compared to < 10 mm (standard MD 0.58; 95%CI: 0.06, 1.10; P = 0.03). Most of the patient's limb gets lengthened after TKA; however, it affects the functional outcome when the LLD is more than equal to 10 mm.