A whole-joint, unidimensional, irreversible, and fine-grained MRI knee osteoarthritis severity score, based on cartilage, osteophytes and meniscus (OA-COM)

PLoS One. 2021 Oct 14;16(10):e0258451. doi: 10.1371/journal.pone.0258451. eCollection 2021.

Abstract

Objective: To develop a whole-joint, unidimensional, irreversible, and fine-grained MRI knee osteoarthritis (OA) severity score, based on cartilage, osteophytes and meniscus (OA-COM), and to predict progression across different severity states using OA-COM as outcome and clinical variables as predictors.

Methods: Population-based knee pain cohort aged 40-79 was assessed at baseline and 7-year follow-up. OA-COM score was defined as the sum of MRI scores for cartilage, osteophytes and menisci, measured at 6, 8 and 6 sites, total score 0-54. To anchor severity levels, we fit cross-sectional logistic models using OA-COM to predict Kellgren-Lawrence (KL) grades in subsets at or one point below each grade. OA-COM threshold scores were selected on sensitivity, specificity, positive and negative predictive value. We developed longitudinal logistic models for OA-COM progression over each threshold over 7 years. Potential predictors included age, sex, BMI, malalignment, physical exam effusion, quadriceps weakness, and crepitus, selected on area under the receiver operating characteristic curve (AUC) and Akaike's Information Criterion (AIC).

Results: Optimal OA-COM thresholds were 12, 18, 24 and 30, for KL grades 1 to 4. Significant predictors of progression (depending on threshold) included physical exam effusion, malalignment and female sex, with other selected predictors age, BMI and crepitus.

Conclusion: OA-COM (0-54 range) is a whole-joint, unidimensional, irreversible, and fine-grained MRI OA severity score reflecting cartilage, osteophytes and menisci. OA-COM scores 12, 18, 24 and 30 are equivalent to KL grades 1 to 4, while offering fine-grained differentiation of states between KL grades, and within pre-radiographic disease (KL = 0) or late-stage disease (KL = 4). In modeling, several clinical variables predicted progression across different states over 7 years.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Age Factors
  • Aged
  • Area Under Curve
  • Body Mass Index
  • Cartilage, Articular / diagnostic imaging*
  • Cohort Studies
  • Female
  • Humans
  • Knee Joint / diagnostic imaging
  • Logistic Models
  • Magnetic Resonance Imaging*
  • Male
  • Meniscus / diagnostic imaging*
  • Middle Aged
  • Osteoarthritis, Knee / diagnosis*
  • Osteoarthritis, Knee / pathology
  • Osteophyte / diagnostic imaging
  • Osteophyte / pathology*
  • ROC Curve
  • Severity of Illness Index

Grant support

This cohort study was funded by grants from the Canadian Institutes of Health Research (#89890, Cibere; #89997, Cibere), the Canadian Arthritis Network (01-MNO-09N, Cibere) and The Arthritis Society (TAS04/0063, Cibere). Dr. Cibere was supported by an Investigator Award from The Arthritis Society (INS-12-027). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.