The infants who have mature hip on ultrasonography but have risk factors of developmental dysplasia of the hip are required radiographic examination

OBJECTIVES: This study aims to evaluate the short-term results of infants who were radiologically diagnosed with developmental dysplasia of the hip (DDH), but in whom hip development was normal ultrasonographically. PATIENTS AND METHODS: Between January 2018 and September 2020, a total of 15 infants (2 males, 13 females; median age: 5 months; range, 4 to 6 months) who were diagnosed with DDH radiologically and treated were retrospectively analyzed. Hip ultrasonography was used for early diagnosis, treatment, and for follow-up in infants up to six months of age. While the ultrasonographic findings were normal, radiography was performed in infants between four to six months of age who were at risk for DDH. RESULTS: Fifteen patients (22 hips) were diagnosed with DDH radiologically and treated. Radiologic dysplasia continued in seven hips of five patients during short-term follow-up. CONCLUSION: These results suggest that ultrasonographic hip maturation may not be consistent with normal hip development in infants, particularly in those who are at risk for DDH. In infants with DDH which is confirmed by radiography (less than 6 months of age), the diagnosis may be missed on ultrasonographic examination.