Prevalence of radiographic findings associated with hip dysplasia in a population-based cohort of 2081 19-year-old Norwegians

Abstract

In Norway total joint replacement after hip dysplasia is reported more commonly than in neighbouring countries, implying a higher prevalence of the condition. We report on the prevalence of radiological features associated with hip dysplasia in a population of 2081 19-year-old Norwegians. The radiological measurements used to define hip dysplasia were Wiberg's centre-edge (CE) angle at thresholds of < 20° and < 25°, femoral head extrusion index < 75%, Sharp's angle > 45°, an acetabular depth to width ratio < 250 and the sourcil shape assessed subjectively. The whole cohort underwent clinical examination of their range of hip movement, body mass index (BMI), and Beighton hypermobility score, and were asked to complete the EuroQol (EQ-5D) and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC). The prevalence of hip dysplasia in the cohort varied from 1.7% to 20% depending on the radiological marker used. A Wiberg's CE angle < 20° was seen in 3.3% of the cohort: 4.3% in women and 2.4% in men. We found no association between subjects with multiple radiological signs indicative of dysplasia and BMI, Beighton score, EQ-5D or WOMAC. Although there appears to be a high prevalence of hip dysplasia among 19-year-old Norwegians, this is dependent on the radiological parameters applied.

The Prevalence of Radiographic Findings of Structural Hip Deformities in Female Collegiate Athletes

“…10,18 Other studies used a less stringent cutoff of 25°and reported a prevalence of 4% to 23% in female European and Japanese cohorts. 10,17,42 The increased prevalence in the present study may be explained in part by differences in the technique used to measure LCEA. In the present study, the LCEA was measured to the lateral margin of the sclerotic line, 27 which, in some cases, can result in a smaller LCEA than measurements made to the lateral border of the acetabular rim.…”

Screening Strategies for Hip Dysplasia: Long-term Outcome of a Randomized Controlled Trial

“…A universal strategy with higher treatment rates did not seem to cause higher rates of AVN even though abduction treatment may place hips at risk. We have previously shown that based on existing cutoff values the prevalence of acetabular dysplasia (ie, at least 1 hip) ranges from 1.7% to 20% in this cohort, 18 with the lowest value based on the subjective assessment of the sourcil shape, and the highest value based on the borderline CE angle. The prevalence based on the dysplastic CE angle was 3.3%.…”

“…5 We chose to assess the most common quantitative measurements (ie, CE angle, FHEI, ADR, and Sharp' s angle), and also a subjective evaluation of dysplasia. 18 The strengths of our study include a large original RCT (11 925 infants) as the basis for this follow-up study, with standard protocols that remained unchanged throughout the whole RCT period. This maturity review also followed a highly standardized radiographic protocol.…”

“…31,32 There is no clear consensus on the definition of acetabular dysplasia at skeletal maturity. 18 To perform a group comparison of acetabular dysplasia as a long-term outcome, we chose to assess the most common radiographic measurements and findings associated with acetabular dysplasia. For the CE angle, we also calculated the rates of the often used borderline group, for detection of differences at a level in between normal and dysplastic hips.…”

“…18 This wide range highlights the challenge of defining acetabular dysplasia. Based on the original RCT, we hypothesized that at skeletal maturity there would be no difference between the 3 trial groups in the rates of radiographic findings associated with acetabular dysplasia or early degenerative change.…”