Is the atrophic phenotype of tibiofemoral osteoarthritis associated with faster progression of disease? The MOST study

Abstract

Objective: To assess the associations of atrophic tibiofemoral osteoarthritis (OA) with progression of radiographic joint space narrowing (JSN) and magnetic resonance imaging (MRI)-defined progression of cartilage damage.

Design: Participants of the Multicenter Osteoarthritis (MOST) Study with available radiographic and MRI assessments at baseline and 30 months were included. The atrophic OA phenotype was defined as Osteoarthritis Research Society International (OARSI) grades 1 or 2 for JSN and grade 0 for osteophytes. Based on MRI, atrophic OA was defined as tibiofemoral (TF) cartilage damage grades ≥3 in at least 2 of 10 subregions with absent or tiny osteophytes in all TF subregions. Progression of JSN and cartilage loss on MRI, was defined as (1) no, (2) slow, and (3) fast progression. Co-variance and logistic regression with generalized estimated equations were performed to assess the association of atrophic knee OA with any progression, compared to non-atrophic OA knees.

Results: A total of 476 knees from 432 participants were included. There were 50 (10.5%) knees with atrophic OA using the radiographic definition, and 16 (3.4%) knees with atrophic OA using MRI definition. Non-atrophic OA knees more commonly exhibited fast progression of JSN and cartilage damage. Logistic regression showed that the atrophic phenotype of knee OA was associated with a decreased likelihood of progression of JSN and cartilage loss.

Conclusion: In this sample, the atrophic phenotype of knee OA was associated with a decreased likelihood of progression of JSN and cartilage loss compared to the non-atrophic knee OA phenotype.

Keywords: Magnetic resonance imaging; Osteoarthritis; Phenotype; Radiography.

Conflict of interest statement

Conflict of Interest

Michel D. Crema, Frank W. Roemer, and Monica D. Marra are stockholders of Boston Imaging Core Lab (BICL), LLC. Ali Guermazi is president of BICL, LLC. He is also a consultant for MerckSerono, Genzyme, Novartis, Stryker, and AstraZeneca. There is no conflict of interest for the remaining authors.

Copyright © 2017 Osteoarthritis Research Society International. Published by Elsevier Ltd. All rights reserved.

Figures

Figure 1

Flow chart of subjects included in the analysis.

Figure 2

Subregional division of tibiofemoral compartments using the WORMS system. The anterior and posterior horns of menisci serve as the reference for defining 5 tibiofemoral regions in each compartment: A=anterior; C=central, P=posterior. The anterior (A) regions of the femoral condyles are part of the patellofemoral compartment.

Figure 3

Example of atrophic tibiofemoral osteoarthritis on radiography and MRI. A. anteroposterior fixed-flexion radiograph shows marked medial joint space narrowing consistent with a grade 2 according to the OARSI atlas and grade 3 according to the Kellgren-Lawrence scale. There are no marginal osteophytes medial or laterally. According to our definition this knee qualifies as being atrophic. B. Corresponding sagittal MRI shows marked full thickness cartilage loss at the central region of the medial femur consistent with grade 5 cartilage damage according to the WORMS scale. Note degenerative maceration of the posterior horn of the medial meniscus.

Figure 3

Example of atrophic tibiofemoral osteoarthritis on radiography and MRI. A. anteroposterior fixed-flexion radiograph shows marked medial joint space narrowing consistent with a grade 2 according to the OARSI atlas and grade 3 according to the Kellgren-Lawrence scale. There are no marginal osteophytes medial or laterally. According to our definition this knee qualifies as being atrophic. B. Corresponding sagittal MRI shows marked full thickness cartilage loss at the central region of the medial femur consistent with grade 5 cartilage damage according to the WORMS scale. Note degenerative maceration of the posterior horn of the medial meniscus.