Osteoarthritis of the hip and acetabular dysplasia in Nigerian men

To determine the prevalence of osteoarthritis (OA) of the hip and of acetabular dysplasia and the association between these conditions in 63 male patients (126 hips) aged 60 to 75 years who had undergone intravenous urography for nonarthritic indications at the University of Maiduguri Teaching Hospital, Nigeria.

Two definitions of radiographic OA were employed: the first based on joint space measurement and the second on global assessment of features of OA. Acetabular dysplasia was defined as a center-edge angle of <25 degrees or an acetabular depth of <9 mm. Results were compared with a British study that used similar methods.

The prevalence of a minimal joint space < or = 2.5 mm was 7.0% in the hips of Nigerian men compared with 13.2% in the British study. The prevalence of acetabular dysplasia in the Nigerian population based on center-edge angle and acetabular depth was 3.3 and 2.9%, respectively. No dysplastic hip in the Nigerian population, defined by either measurement, showed osteoarthritic change.

Our study shows a lower prevalence of hip OA in elderly Nigerian men compared with similar aged men in Britain. The prevalence of dysplasia in the 2 populations was similar, and so cannot account for the difference in OA prevalence. Furthermore, shallow acetabula were not associated with OA of the hip in the Nigerian men.