Objectives Meniscal pathology in which the aetiology is often unclear is a frequent finding on knee MRI. This study investigates potential risk factors for medial meniscal lesions or extrusion in middle-aged and elderly persons.
Methods Prospective cohort study using population-based subjects from Birmingham, Alabama and Iowa City, Iowa, USA (the Multicenter Osteoarthritis Study). 644 men and women aged 50–79 years with or at high risk of knee osteoarthritis (Kellgren and Lawrence grade 0–2) but with normal medial meniscal status at baseline were studied. Paired baseline and 30-month 1.0 T knee MRI were scored for meniscal lesions and extrusion (pathology) and the following systemic, knee-specific and compartment-specific potential risk factors were evaluated: age, sex, body mass index, bony enlargement of finger joints, knee trauma, leg-length inequality and knee alignment.
Results Of 791 knees, 77 (9.7%) had medial meniscal pathology at 30 months follow-up. 61 of the 77 (81%) had no report of trauma during follow-up. Including all potential risk factors in the multivariable model, the adjusted OR for medial meniscal pathology was 4.14 (95% CI 2.06 to 8.31) for knee trauma during follow-up, 1.64 (1.00 to 2.70) for five or more bony enlargements of finger joints (vs ≤4) and 2.00 (1.18 to 3.40) for varus alignment (vs not varus) at baseline examination. Obesity was a risk factor for the development of meniscal extrusion, OR 3.04 (1.04 to 8.93) but not for meniscal lesions, OR 1.15 (0.52 to 2.54).
Conclusions Apart from knee trauma, possible generalised osteoarthritis, expressed as multiple bony enlargements of finger joints, varus alignment and obesity are risk factors for medial meniscal pathology.
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Funding The Multicenter Osteoarthritis (MOST) Study is a cooperative epidemiological study of knee osteoarthritis funded by the National Institute on Aging (NIA): DTF, 1 U01 AG18820; Torner, 1 U01 AG18832; CEL, 1 U01 AG18947; MCN, 1 U01 AG19069. ME is supported by the Swedish Research Council and the Faculty of Medicine, Lund University, Sweden.
Competing interests AG is a shareholder of Boston Imaging Core Lab, LLC (BICL), Boston, Massachusetts, USA, a company providing radiological image assessment services, and Synarc Inc, and consultant to Merck Serono, Novartis, Genzyme, Facet Solutions and Stryker. FWR and MDC are shareholders of BICL. None of the other authors have declared any conflict of interest.
Patient consent Obtained.
Ethics approval This study was conducted with the approval of the institutional review boards from Boston University, University of Iowa and University of Alabama.
Provenance and peer review Not commissioned; externally peer reviewed.