IS SECONDARY RADIOGRAPHIC FOLLOW-UP OF INFANTS WITH FAMILY HISTORY OF DDH NECESSARY?

Abstract

Introduction: It is common practice to screen the hips of infant with a family history of DDH clinically and ultra-sonographically in selective screening programmes. The practice of regular radiographic follow-up of infants with a positive family history of Developmental Hip Dysplasia (DDH) is based on the widespread belief that Primary Acetabular Dysplasia is a genetic disorder that can occur in the absence of frank hip subluxation or dislocation¹. It has been our practice to obtain a 6 – 12 month screening radiograph in such patients but this practice is not conclusively supported in the literature.

Materials and Methods: We reviewed all such infants who had a normal clinical and ultrasound examination of the hips at the 6–8 week screening examination but who, because of the family history underwent further radiographic screening after a 6–12 month interval. The radiographs of all such infants (n=77) were analysed for any signs of late hip dysplasia.

Results and Discussion: Sixty six infant had normal X rays at the 6–8 month assessment and were discharged. The remaining eleven patients had acetabular angles at the upper end of the normal range for age and were reviewed again with further radiographs at 12 months. At this stage ten patients were normal and were discharged. The remaining patient was reviewed again at 18 months and 24 months and finally proved to be normal and was discharged. The result of a postal survey has suggested that majority of BSCOS members do not get follow up x-ray done if the clinical and ultrasound scan is normal at screening visit.

Conclusion: All of the seventy seven patients eventually developed normal radiographs and we question the need for radiographic follow up of infants with a family history of DDH but who have a normal clinical examination and ultrasound scan at 6–8 weeks.