Acetabular dysplasia in the Sami population: a population study among Sami in north Norway.

OBJECTIVES The overall aim of this study was to evaluate the acetabular coverage of the femoral head as measured by the centre-edge (CE) angle of Wiberg and to evaluate any association between low back pain and hip dysplasia in a Sami-dominated area (the municipalities of Karasjok and Kautokeino) in north Norway. STUDY DESIGN A cross-sectional population-based study, which included questionnaires and a radiographic examination of the hips. METHODS A total of 1723 individuals were invited to participate in a general health survey. Of these, 78.2% attended the screening and filled out a questionnaire that included questions about ethnicity and symptoms of back problems; 836 participants returned the questionnaire. Back problems were reported by 210 participants, the rest had no complaints. All 210 participants with back problems and a random sample of 206 with no back pain were invited for a radiographic examination, 75% and 76%, respectively, showed up for the examination. RESULTS The centre-edge (CE) angle of Wiberg was found to be 28 (+/-7) and 27 (+/-7) degrees for the left and right hip, respectively. Our results showed that 17% of the Sami had definite dysplasia, 21% had light dysplasia and 62% had normal hip joints. Thus, 38% of the Sami had more or less dysplastic hips. The oldest participants had a significantly smaller CE-angle than the younger ones. However, no associations were found between acetabular dysplasia and back complaints. CONCLUSIONS A high prevalence of hip dysplasia was found in this Sami-dominant area. No significant association could be found between low back pain and dysplasia.