Background In western countries, knee osteoarthritis (OA) is the third osteoarthritic location in terms of prevalence, with a ratio hip/knee OA of 1:2 to 1:3. However, in Asian/African countries, this ratio is much lower, of 1:27 in Algeria and 1:40 in China. A comparative study between American and Chinese hips in elderly women found more impingement and asphericity in hips of white women.

Objectives We conducted this study to find out morphometric differences between Algerian and American hips that may explain such differences in hip OA prevalence.

Methods A morphometric study was performed on 200 hips of 100 Algerian healthy female subjects, aged ≥60 years and compared with values of 200 American hips of the Study of Osteoporotic Fractures (SOF). Were mesured and compared the following dysplasia and impingement parameters: lateral center-edge angle, impingement angle, acetabular slope, femoral head-to-femoral neck ratio and crossover sign. Comparisons were made using t tests for continuous variables and z tests for proportions. Inta- and inter-observer intraclass correlation for Algerian measures were calculated.

Results The intra- and inter-observer intraclass correlation were good to excellent (0.91 to 0.97 and 0.79 to 0.89, resp.). Different values are shown in Table 1.

Conclusions Compared with American women >60 years, Algerian women have distinct differences in their morphometric values, with lower mean impingement angles and more important Lateral center-edge angles. These data suggest a more common asphericity and impingement in Algerians, which theoritically predisposes to more hip OA lesions. We think that this abnormality is largely offset by the almost total lack of acetabular retroversion in Algerians (3% in Algerians VS 81% in Americans), which may play a protective role against the anterior femoroacetabular impingement.

Disclosure of Interest None declared