CC BY-NC-ND 4.0 · Indian J Radiol Imaging 2023; 33(04): 484-488
DOI: 10.1055/s-0043-1770085
Original Article

The Linear Coronal Knee Offset (LCKO)—Preliminary Study of New Method of Measuring Knee Varus/Valgus Malalignment

Ahmed Saad
1   Department of Orthopaedics, Royal Orthopaedic Hospital, Birmingham, United Kingdom
2   Department of Radiology, Royal Orthopaedic Hospital, Birmingham, United Kingdom
Akash Sharma
3   Department of Arthroplasty, Royal Orthopaedic Hospital, Birmingham, United Kingdom
Yuvraj Agrawal
3   Department of Arthroplasty, Royal Orthopaedic Hospital, Birmingham, United Kingdom
4   Department of Orthopaedics, Southport and Ormskirk Hospital, Southport, United Kingdom
5   Department of Musculoskeletal Radiology, Royal Orthopedic Hospital, Birmingham, United Kingdom
› Author Affiliations
Funding None.


Introduction Considerable attention is focused on preoperative templating of radiological images in patients undergoing total knee arthroplasty to obtain optimal alignment and outcome. Several radiological measurements have been described.

Purpose In this study, we illustrate a new linear measurement: The linear coronal knee offset (LCKO) that can be used to analyze the coronal configuration on long leg alignment radiographs commonly undertaken during preoperative templating.

Methods A retrospective search was performed of our Picture Archiving and Communication System and Radiology Information System to identify 100 lower limbs anteroposterior, weight bearing, long leg alignment view radiographs of patients referred to knee clinics over 1 year with knee pain.

Demographic details, clinical indication, standard radiological measurement of the anatomical tibiofemoral angle, and the LCKO were measured and data were analyzed using Student's t-test. In addition, intraclass correlation coefficient was used to analyze for intraclass reliability.

Results The average age of patients was 36.3 years (range: 12–80 years) with a male predominance. The LCKO was statistically significant between the three cohorts of patients. The mean LCKO in normal cohorts was 0.24 cm, varus was −0.6 cm, and valgus was 1.72cm. There was good inter and interobserver reliability (Kappa of 0.8 and 0.8, respectively).

Conclusion The novel LCKO measurement provides a simpler method in assessing coronal lower limb malalignment and can easily identify a normal, varus, or valgus knee deformity.

Publication History

Article published online:
26 June 2023

© 2023. Indian Radiological Association. This is an open access article published by Thieme under the terms of the Creative Commons Attribution-NonDerivative-NonCommercial License, permitting copying and reproduction so long as the original work is given appropriate credit. Contents may not be used for commercial purposes, or adapted, remixed, transformed or built upon. (

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