Late-presenting DDH, defined as diagnosis after 3 months of age, is uncommon, occurring at an estimated rate of 0.22 per 1,000 births [55]. At this age, the clinical assessment is less reliable and imaging is often required to confirm the diagnosis. By 8 to 12 weeks of age, the capsule laxity decreases, muscle tightness increases, and the Barlow and Ortolani maneuvers may not be positive regardless of the status of the femoral head. Thus, the finding of limited hip abduction becomes the most important screening method in older children. However, currently there is no consensus on the reliability of this test for diagnosing DDH [5], with one study demonstrating a positive predictive value of 40% for DDH that can increase up to 55% after 8 weeks of age [36], while another study demonstrated no correlation between a positive abduction test and an abnormal acetabular angle [66]. Other screening methods, such as the findings of asymmetric skin folds in the proximal thigh and shortening of the limb on the dislocated side, lack specificity for the diagnosis of DDH [66]. These inconsistencies among various studies may reflect differences in patient selection or inclusion, expertise of the examiners, and the defined gold standard [1,67-69]. US Hips The AAP and AAOS do not advocate the use of US for the screening of DDH after 4 to 5 months [1,20]. There is limited evidence on the use of US for screening of DDH beyond 4 months. A study that obtained anteroposterior radiographs in patients who are 4 to 6 months of age with positive US found that US overdiagnosed DDH in 40% of patients [58]. Radiography Pelvis Shortly after the appearance of the ossific nucleus, pelvic radiography becomes the preferred confirmatory imaging modality, as it allows for the assessment of the femoral head ossific nucleus, the development of the proximal femur, and bony acetabular morphology [1].
Developmental Dysplasia of the Hip Child. Late-presenting DDH, defined as diagnosis after 3 months of age, is uncommon, occurring at an estimated rate of 0.22 per 1,000 births [55]. At this age, the clinical assessment is less reliable and imaging is often required to confirm the diagnosis. By 8 to 12 weeks of age, the capsule laxity decreases, muscle tightness increases, and the Barlow and Ortolani maneuvers may not be positive regardless of the status of the femoral head. Thus, the finding of limited hip abduction becomes the most important screening method in older children. However, currently there is no consensus on the reliability of this test for diagnosing DDH [5], with one study demonstrating a positive predictive value of 40% for DDH that can increase up to 55% after 8 weeks of age [36], while another study demonstrated no correlation between a positive abduction test and an abnormal acetabular angle [66]. Other screening methods, such as the findings of asymmetric skin folds in the proximal thigh and shortening of the limb on the dislocated side, lack specificity for the diagnosis of DDH [66]. These inconsistencies among various studies may reflect differences in patient selection or inclusion, expertise of the examiners, and the defined gold standard [1,67-69]. US Hips The AAP and AAOS do not advocate the use of US for the screening of DDH after 4 to 5 months [1,20]. There is limited evidence on the use of US for screening of DDH beyond 4 months. A study that obtained anteroposterior radiographs in patients who are 4 to 6 months of age with positive US found that US overdiagnosed DDH in 40% of patients [58]. Radiography Pelvis Shortly after the appearance of the ossific nucleus, pelvic radiography becomes the preferred confirmatory imaging modality, as it allows for the assessment of the femoral head ossific nucleus, the development of the proximal femur, and bony acetabular morphology [1].