Bone geometry of the hip is associated with obesity and early structural damage – a 3.0 T magnetic resonance imaging study of community-based adults

Bone geometry of the hip is associated with obesity and early structural damage – a 3.0 T magnetic resonance imaging study of community-based adults

Arthritis Research & Therapy, April 2015

25925369

Andrew J Teichtahl, Yuanyuan Wang, Sam Smith, Anita E Wluka, Michael Zhu, Donna Urquhart, Graham G Giles, Richard O’Sullivan, Flavia M Cicuttini

The mechanism by which obesity increases the risk of hip osteoarthritis (OA) is unclear. One mechanism may be by mediating abnormalities in bony geometry, which may in turn be associated with early structural abnormalities, such as cartilage defects and bone marrow lesions (BMLs). 141 older adults with no diagnosed hip OA had weight and body mass index (BMI) measured between 1990 and 1994 and again in 2009-10. Acetabular depth and lateral centre edge angle (LCEA), both measures of acetabular over-coverage, as well as femoral head cartilage volume, cartilage defects and BMLs were assessed with 3.0 T magnetic resonance imaging (MRI) performed in 2009-10. Current BMI, weight and weight gain were associated with increased acetabular depth and LCEA (all p ≤ 0.01). For every one millimetre increase in acetabular depth, femoral head cartilage volume reduced by 59 mm(3) (95% Confidence Interval (CI) 98 mm(3) to 20 mm(3), p < 0.01). Greater acetabular depth was associated with an increased risk of cartilage defects (Odds Ratio (OR) 1.22, 95% CI 1.03 - 1.44, p = 0.02) and BMLs (OR 1.29, 95% CI 1.01 - 1.64, p = 0.04) in the central region of the femoral head. LCEA was not associated with hip structure. Obesity is associated with acetabular over-coverage. Increased acetabular depth, but not the LCEA, is associated with reduced femoral head cartilage volume and an increased risk of cartilage defects and BMLs. Minimising any deepening of the acetabulum, for example through weight management, might help to reduce the incidence of hip OA.