Association of MRI-detected Tibiofemoral Subchondral Bone Marrow Lesions with Prevalent And Incident Subchondral Bone

Title:

The Association of MRI-detected Tibiofemoral Subchondral Bone Marrow Lesions with Prevalent And Incident Subchondral Bone Attrition: The MOST Study

Author(s):

Frank W. Roemer¹, Ali Guermazi¹, Tuhina Neogi¹, Yanyan Zhu¹, Yuqing Zhang¹, M. K. Javaid², John A. Lynch², Michel D. Crema¹, Monica D. Marra¹, James Torner³, Cora E. Lewis⁴, David T. Felson¹, Michael C. Nevitt². ¹BUSM, Boston, MA; ²UCSF, San Francisco, CA; ³U. of Iowa, Iowa City, IA; ⁴UAB, Birmingham, AL

Purpose: Subchondral bone attrition (SBA) is radiologically defined as depression or flattening of the subchondral bony surface unrelated to gross fracture. It has been demonstrated that bone marrow edema-like lesions (BMLs) in osteoarthritis (OA) are related to focal overloading due to malalignment and that these lesions may be markers of compressive overload. As it is unknown what causes bone attrition in OA, one explanation could be subchondral remodeling and microfractures due to chronic overload. Hence, we evaluated the association of subchondral BMLs at baseline (BL) with prevalent SBA in the same subregion cross-sectionally and with incident SBA longitudinally.

Methods: The Multicenter Osteoarthritis (MOST) Study is a NIH-funded longitudinal observational study of individuals who have or are at high risk for knee OA. All subjects with available BL and 30-months follow-up (FU) MRIs (1.0 T extremity MRI) were included. Two musculoskeletal radiologists read the MRIs (FWR, AG) according to the WORMS scoring system. The tibiofemoral joint was subdivided into 10 subregions. Subchondral BMLs and SBA were scored semiquantitatively from 0 to 3. We evaluated the association of prevalent BMLs at BL with the presence of prevalent and incident SBA on a per-subregion basis using logistic regression with generalized estimating equations to account for correlations among the subregions within a knee (using 1 knee per person). All analyses were adjusted for age, gender, BMI and ethnicity. Subregions without subchondral BMLs at BL were defined as the reference group for the analysis. We also cross-sectionally evaluated the association of BL BML size and presence of BL SBA.

Results: Knees with MT had approximately double the frequency of cartilage loss in all subregions compared to knees with no MT, with a significant (p<0.01) odds-ratio of 1.7 (Table 1). MX was associated with increased cartilage loss (OR=1.7, p<0.02) independently of MT. MX was preferentially associated with cartilage loss in central and anterior regions compared to posterior regions where the MX effect was reduced (p<0.03 for interaction with subregion).

Conclusions: Medial MT and MX in the medial direction independently predicted medial compartment cartilage loss. Association of cartilage loss with MT was throughout the medial compartment. The association of MX with cartilage loss was limited to sites that are weight bearing in or close to extension. These data suggest that medial meniscal tears and extrusion affect the risk and anatomical distribution of cartilage loss.

Disclosures:

J.A. Lynch, None; M.K. Javaid, None; F. Roemer, None; A. Guermazi, None; I. Tolstykh, None; M. Englund, None; C.E. McCulloch, None; L. Sharma, None; C.E. Lewis, None; J. Torner, None; D. Felson, None; M.C. Nevitt, None.