Peter Jacob Haar PhD, Presenter: Nothing to Disclose

Jean-Denis Laredo MD, Abstract Co-Author: Research Consultant, Cardinal Health, Inc Research Consultant, Laurane Medical Research Consultant, onTargetjobs Research grant, SERVIER

R. Nick Bryan MD, PhD, Abstract Co-Author: Nothing to Disclose

Medial meniscus subluxation and tibial coverage are important findings in osteoarthritis of the knee, and simple reproducible approaches to quantify both findings could have scientific and clinical utility. We studied the reproducibility of two standardized methods of quantification of medial meniscus subluxation on coronal MR images: (1) meniscus subluxation ratio (SR), or the portion of the meniscus overhanging the tibial plateau; and (2) tibial coverage ratio (TCR), or the portion of the medial tibial plateau covered by the medial meniscus.

Two independant readers measured SR and TCR on coronal proton density MR image sets of patients with varying degrees of osteoarthritis (n = 61) and on multiple repeated coronal T1-weighted MR image sets taken on different days (n = 7). The slice was selected in which the transverse dimension of the medial meniscus was the narrowest. If the narrow segment of the medial meniscus appeared equal on two or more images, the slice in which the edge of the meniscus was most medial was selected.

The intraobserver correlation coefficient for SR was 0.81 [0.70 – 0.88], and for TCR was 0.82 [0.72 – 0.89]. The interobserver correlation coefficient for SR was 0.90 [0.84 – 0.94], and for TCR was 0.93 [0.87 – 0.96], a difference which was not significant (p = 0.12). For 7 patients repositioned and reimaged 5 times, the intraclass correlation coefficient for SR was 0.81 [0.61 – 0.91], and the ICC for TCR was 0.88 [0.74 – 0.95].

The two proposed methods for measuring medial meniscus subluxation and tibial coverage are reproducible for multiple observations by the same observer, between different observers, and across multiple different studies of the same patient.

Medial meniscus subluxation and tibial coverage can be reproducibly measured on coronal MR images.

Haar, P, Laredo, J, Bryan, R, Reproducible MR Measurements of Meniscus Subluxation and Tibial Coverage in Osteoarthritis of the Knee.  Radiological Society of North America 2010 Scientific Assembly and Annual Meeting, November 28 - December 3, 2010 ,Chicago IL. http://archive.rsna.org/2010/9013998.html