Radiographically normal knees with contralateral joint space narrowing display greater change in cartilage transverse relaxation time than those with normal contralateral knees: a model of early OA? - data from the Osteoarthritis Initiative (OAI)

Abstract

Objective: To develop a model of early osteoarthritis, by examining whether radiographically normal knees with contralateral joint space narrowing (JSN), but without contralateral trauma history, display greater longitudinal cartilage composition change (transverse relaxation time; T2) than subjects with bilaterally normal knees.

Methods: 120 radiographically normal knees (Kellgren Lawrence grade [KLG] 0) from the Osteoarthritis Initiative were studied. 60 case knees displayed definite contralateral radiographic knee osteoarthritis (KLG ≥ 2) whereas 60 reference subjects were bilaterally KLG0, and were matched 1:1 to cases based on age, sex, and BMI. All had multi-echo spin-echo MRI acquired at year (Y) 1 and 4 follow-up, with cartilage T2 being determined in superficial and deep cartilage layers across 16 femorotibial subregions. T2 across all regions was considered the primary analytic focus.

Results: Of 60 KLG0 case knees (30 female, age: 65.0 ± 8.8 y, BMI: 27.6 ± 4.4 kg/m2), 21/22/13/4 displayed contralateral JSN 0/1/2/3, respectively. The longitudinal increase in the deep layer cartilage T2 between Y1 and Y4 was significantly greater (P = 0.03; Cohen's D 0.50) in the 39 KLG0 case knees with contralateral JSN (1.2 ms; 95% confidence interval [CI] [0.4, 2.0]) than in matched KLG0 reference knees (0.1 ms; 95% CI [-0.5, 0.7]). No significant differences were identified in superficial T2 change. T2 at Y1 was significantly greater in case than in reference knees, particularly in the superficial layer of the medial compartment.

Conclusions: Radiographically normal knees with contralateral, non-traumatic JSN represent an applicable model of early osteoarthritis, with deep layer cartilage composition (T2) changing more rapidly than in bilaterally normal knees. CLINICALTRIALS.

Gov identification: NCT00080171.

Keywords: Cartilage T2; Cartilage composition; Cartilage transverse relaxation time; MRI; Model of early osteoarthritis.

Conflict of interest statement

CONFLICTS OF INTEREST

Dr. Maschek and Dr. Wirth are part time employees and co-owners of Chondrometrics GmbH. Dr. Roemer is a part time employee of Chondrometrics, and is shareholder, CMO and Director of Research of Boston Imaging Core Lab (BICL), LLC. Dr. Duda and Dr. Sharma have no conflicts to declare. Dr. Eckstein is CEO/CMO and co-owner of Chondrometrics GmbH, and he has provided consulting services to Merck KGaA, Bioclinica, Samumed, Tissuegene, Servier, Galapagos and Roche. He also has received speaker honoraria from Medtronic.

Copyright © 2019 Osteoarthritis Research Society International. Published by Elsevier Ltd. All rights reserved.

Figures

Figure 1:

Illustration showing the cartilage T2 measurements in the central part of the medial femoral condyle (cMF) and the medial tibia (MT) and the subregional analysis; a) color-coded T2 map, b) superficial (magenta) and deep (blue) cartilage layers, c) Illustration of the 16 subregions in the medial (MFTC) and lateral (LFTC) femorotibial compartment, d) Illustration showing the central (red), external (green), internal (blue), anterior (turquoise), and posterior (yellow) subregions of the medial (MT) and lateral tibia (LT), e) Illustration showing the central (red), external (green), internal (blue) subregions of the medial (cMF) and lateral femoral condyle (cLF).

Figure 2:

Bar graphs showing the cartilage T2 times in the superficial and deep layer of the entire femorotibial joint at the Y1 and the Y4 visit in case knees with CL JSN (n=39) and in matched reference knees (n=39).