Iidaka T, et al. – The clinicians applied the large–scale population–based cohort of the Research on Osteoarthritis/osteoporosis Against Disability (ROAD) study, in order to investigate the radiographic measurements of the hip joint and their associations with hip pain in Japanese men and women. They revealed that minimum joint space width (mJSW), central–edge (CE) angle, acetabular depth–to–width ratio (ADR), and acetabular head index (AHI) were associated with hip pain.

Methods

• This study enrolled 2,963 participants (1,040 men, 1,923 women; mean age, 70.2 years). 
• With an anteroposterior view under weight–bearing, all participants underwent radiographic examinations of both hips.
• Minimum joint space width (mJSW), central–edge (CE) angle, acetabular depth–to–width ratio (ADR), and acetabular head index (AHI) were calculated.
• In multivariable logistic–regression analysis, associations between these radiographic measurements and hip pain were evaluated by calculating odds ratios.
• Acetabular dysplasia was defined as a CE angle <20°.

Results

• Investigations displayed that mean radiographic measurements of the hip joint for men were: mJSW, 3.8 mm; CE angle, 30.6°; ADR, 262.1 per 1000; and AHI, 81.4%.
• For women, these values were: mJSW, 3.4 mm; CE angle, 29.9°; ADR, 262.7 per 1000; and AHI, 81.2%.
• Associations were seen between hip pain and each of mJSW, CE angle, ADR, and AHI (odds ratio 4.52, 95% confidence interval 3.45–5.97; 1.14, 1.11–1.18; 1.31, 1.24–1.40; and 1.15, 1.12–1.18, respectively). 
• Acetabular dysplasia showed an overall prevalence of 13.9%, and was significantly more prevalent in women than in men (p=0.012).