PURPOSE: Comparison of morphologic and dynamic methods of hip ultrasonography (US) to differentiate normal from abnormal findings in the diagnosis of developmental dysplasia of the hip (DDH). MATERIALS AND METHODS: A total of 6,800 hips in 3,400 infants were examined with US, using the morphological method of Graf, and the dynamic method of Harcke. RESULTS: According to the Graf classification 81.47% of infants had Type 1 (normal hip), 10% Type 2a (physiologic immaturity), 2.44% Type 2b (acetabular dysplasia), 1.05% Type 2c (critical zone hip), 2.89% Type 3 (mildly dislocated), and 2.10% had Type 4 (dislocated) hips. Study in the transverse/neutral plane showed a normal relationship between the femoral head and the acetabulum in the 6,460 hips that were classified as Type 1-2c, that the hip was subluxated in 197 hips of Type 3, and was luxated in 143 hips of Type 4. Dynamic study with stress maneuver of the Type 1-2a hips showed that while 91.48% of the Type 1 hips (n = 5540) were stable and 8.52% were unstable, 92.37% of the Type 2a hips (n = 682) were stable and 7.63% were unstable. Dynamic study was not performed in cases that were diagnosed as Type 2b or worse. Follow-up US showed progression from Type 2a to Type 2b in 2.63% of Type 2a cases. Of the cases, 1.7% that were morphologically normal (Type 1) but unstable in their initial US examination, were revealed to be Type 3 later in the repeat US examination. CONCLUSION: We believe that overtreatment and delayed treatment rates of DDH will be minimized by the use of both morphological and dynamic US methods in the evaluation of the newborn hip.
PURPOSE: Comparison of morphologic and dynamic methods of hip ultrasonography (US) to differentiate normal from abnormal findings in the diagnosis of developmental dysplasia of the hip (DDH). MATERIALS AND METHODS: A total of 6,800 hips in 3,400 infants were examined with US, using the morphological method of Graf, and the dynamic method of Harcke. RESULTS: According to the Graf classification 81.47% of infants had Type 1 (normal hip), 10% Type 2a (physiologic immaturity), 2.44% Type 2b (acetabular dysplasia), 1.05% Type 2c (critical zone hip), 2.89% Type 3 (mildly dislocated), and 2.10% had Type 4 (dislocated) hips. Study in the transverse/neutral plane showed a normal relationship between the femoral head and the acetabulum in the 6,460 hips that were classified as Type 1-2c, that the hip was subluxated in 197 hips of Type 3, and was luxated in 143 hips of Type 4. Dynamic study with stress maneuver of the Type 1-2a hips showed that while 91.48% of the Type 1 hips (n = 5540) were stable and 8.52% were unstable, 92.37% of the Type 2a hips (n = 682) were stable and 7.63% were unstable. Dynamic study was not performed in cases that were diagnosed as Type 2b or worse. Follow-up US showed progression from Type 2a to Type 2b in 2.63% of Type 2a cases. Of the cases, 1.7% that were morphologically normal (Type 1) but unstable in their initial US examination, were revealed to be Type 3 later in the repeat US examination. CONCLUSION: We believe that overtreatment and delayed treatment rates of DDH will be minimized by the use of both morphological and dynamic US methods in the evaluation of the newborn hip.