The acetabulum in Perthes’ disease: A prospective study of 123 children

Abstract

PurposeWe assessed the radiographic changes of the acetabulum during the course of Perthes’ disease and investigated whether they were associated with femoral head sphericity 5 years after diagnosis.MethodsWe studied 123 children with unilateral Perthes’ disease, femoral head necrosis more than 50 % and age at diagnosis 6 years or older. Pelvic radiographs were taken at onset, 1 year and 5 years after diagnosis. Sharp’s angle, acetabular depth-to-width ratio (ADR) and lateral acetabular inclination were measured.ResultsCompared to the unaffected hips, the Perthes’ hips developed significantly higher Sharp’s angles (p < 0.001) and a higher proportion with an upward-sloping lateral acetabular margin (Perthes’ hips: 49 %, unaffected hips 1 %). The mean ADR values were significantly lower on the affected side at all stages (p < 0.001). ADR values at diagnosis were associated with a more spherical femoral head at the 5-year follow-up [odds ratio (OR) 1.012, 95 % confidence interval (CI) 1.002–1.022, p = 0.016]. None of the other acetabular parameters were significantly associated with the femoral head shape 5 years after diagnosis.ConclusionThe acetabulum developed an increasingly dysplastic shape in the course of Perthes’ disease. Early dysplastic changes of the acetabulum were not associated with a poor radiological outcome 5 years after diagnosis. Routine measurement and monitoring of acetabular changes in plain radiographs were of little prognostic value and can, therefore, hardly be recommended in clinical practice.

Ischemic femoral head osteonecrosis in a piglet model causes three dimensional decrease in acetabular coverage

“…The decrease in coverage angle in those quadrants, in addition to the decrease in acetabular anteversion observed in this study, is consistent with previous publications on patients affected by LCPD . It is interesting to note that we did not find a significant difference in the acetabular radius nor in the total area of the acetabulum, which differs from previous clinical studies of patients with LCPD . This may be secondary to differences in measurement, as those studies relied on an AP pelvis radiograph, where in this case the measurement was made using three‐dimensional CT images.…”

“…Much of the research on this topic has been focused on the changes to the femoral head, however, there are also changes that occur which affect the morphology of the acetabulum. Clinical studies examining radiographic changes to the acetabulum have shown articular hypertrophy in the superior and medial aspects of the acetabulum, upward sloping of the lateral margin of the acetabulum, as well as premature fusion of the triradiate cartilage . Subsequent studies have shown that patient's with LCPD were more likely to have acetabular retroversion, and be associated with anterolateral labrum and cartilage damage …”

“…Clinical studies examining radiographic changes to the acetabulum have shown articular hypertrophy in the superior and medial aspects of the acetabulum, upward sloping of the lateral margin of the acetabulum, as well as premature fusion of the triradiate cartilage. [3][4][5] Subsequent studies have shown that patient's with LCPD were more likely to have acetabular retroversion, 6 and be associated with anterolateral labrum and cartilage damage. 7,8 The pathogenesis of femoral head deformity following ischemic osteonecrosis has been studied extensively using the piglet model.…”

“…8,22 It is interesting to note that we did not find a significant difference in the acetabular radius nor in the total area of the acetabulum, which differs from previous clinical studies of patients with LCPD. 5,23 This may be secondary to differences in measurement, as those studies relied on an AP pelvis radiograph, where in this case the measurement was made using three-dimensional CT images.…”

The potential role of variations in juvenile hip geometry on the development of Legg-Calvé-Perthes disease: a biomechanical investigation

“…The average centre-to-centre distance was also significantly higher in LCP (of 3.0 ± 1.3 (SD) mm) when compared with 1.2 ± 0.5 (SD) mm in the normal side. In addition, Huhnstock et al (2014) analysed the changes in the acetabulum in children with unilateral LCP and observed that during the first year after the diagnosis. The acetabular depth-to-width ratio (ADR) decreased when compared with the normal hip, due to a decrease in depth of 10% and an increase in width of 10%.…”