Associations Of Medial Meniscal Tear and Extrusion With The Sites Of Cartilage Loss In The Knee - Results From The Most Study

Title:

Associations Of Medial Meniscal Tear and Extrusion With The Sites Of Cartilage Loss In The Knee - Results from The Most Study

Author(s):

John A. Lynch¹, M. Kassim Javaid², Frank Roemer³, Ali Guermazi³, Irina Tolstykh¹, Martin Englund³, Charles E. McCulloch¹, Leena Sharma⁴, Cora E. Lewis⁵, James Torner⁶, David Felson³, Michael C. Nevitt¹. ¹UCSF, San Francisco, CA; ²Univ. of Oxford, Oxford, United Kingdom; ³Boston University, Boston, MA; ⁴Northwestern University, Chicago, IL; ⁵Univ. of Alabama, Birmingham, AL; ⁶Univ. of Iowa, Iowa City, IA

Purpose: Meniscal damage (tear or extrusion) is associated with incident radiographic OA, joint space loss on x-rays, and cartilage loss seen on MRI. We examined whether medial meniscal tears and extrusion independently predicted medial compartment cartilage loss and whether either is preferentially associated with cartilage loss at specific anatomical sites.

Methods: MOST (Multicenter Osteoarthritis Study) is a NIH funded, 2 center observational study of people aged 50-79 with, or at high risk of developing, knee OA. 1T MRIs of 1011 knees, from baseline (BL) and 30 month follow-up (FU), were read paired by 2 experienced musculo-skeletal radiologists (blinded to clinical/ radiographic status) using the WORMS method. Medial tibio-femoral compartments were scored for cartilage morphology on a 0-6 scale in 5 subregions. Cartilage loss was defined as an increase in subregion score (BL to FU). Medial meniscal tears (MT) and extrusion in the medial direction (MX) (assessed from coronal images) were defined by grade >=1 at BL. We used logistic regression to examine whether MT or MX predicted or altered the frequency of cartilage loss over the 5 subregions. Knees with lateral meniscal damage (N=185) and subregions with BL cartilage score of 6 were excluded. We adjusted for MT, MX, age, sex, BMI, alignment, and knee injury, and used GEE to adjust for correlations within a knee (5 subregions) and 2 knees for some subjects.

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.