Radiographic Follow-up of DDH in Infants: Are X-rays Necessary After a Normalized Ultrasound?
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Eric J Sarkissian1, Wudbhav N Sankar, Xiaowei Zhu
1*Division of Orthopaedic Surgery, The Children's Hospital of Philadelphia †Department of Orthopaedic Surgery, Hospital of the University of Pennsylvania, Philadelphia, PA.
Insights
Long-term radiographic monitoring for developmental dysplasia of the hip (DDH) in infants is crucial. The incidence of residual dysplasia outweighs the minimal risks associated with radiation exposure, supporting continued follow-up.
Area of Science:
- Pediatric Orthopedics
- Radiology
- Developmental Dysplasia of the Hip (DDH)
Background:
- Concerns regarding radiation exposure have led to debate over long-term radiographic follow-up for infants with developmental dysplasia of the hip (DDH) who show normal clinical and ultrasonographic results.
- Assessing the necessity of continued radiographic monitoring is vital, balancing the incidence of residual radiographic dysplasia against radiation risks.
Purpose of the Study:
- To evaluate the importance of ongoing radiographic monitoring in infants with normalized developmental dysplasia of the hip (DDH).
- To compare the incidence of residual radiographic dysplasia with the risks of radiation exposure in this patient group.
Main Methods:
- A retrospective case series reviewed infants with idiopathic DDH over four years.
- Infants with normalized DDH (normal clinical exam and ultrasound by 3.1 months) were monitored with pelvic radiographs at 6 and 12 months.
- Radiation effective dose was calculated using PCXMC software.
Main Results:
- 17% of infants with normalized DDH showed radiographic signs of acetabular dysplasia at 6 months.
- In untreated infants (n=106), 33% had residual dysplasia at 12 months.
- Radiation effective dose from radiographs was minimal (<0.01 mSv).
Conclusions:
- The incidence of radiographic dysplasia in infants with previously normalized DDH is significant.
- These findings suggest that the benefits of radiographic follow-up outweigh radiation risks.
- Radiographic monitoring through walking age may be warranted for early diagnosis and intervention of residual acetabular dysplasia.
Background:
Concerns about radiation exposure have created a controversy over long-term radiographic follow-up of developmental dysplasia of the hip (DDH) in infants who achieve normal clinical and ultrasonographic examinations. The purpose of this study was to assess the importance of continued radiographic monitoring by contrasting the incidence of residual radiographic dysplasia to the risks of radiation exposure.
Methods:
We reviewed a consecutive series of infants with idiopathic DDH presenting to our institution over 4 years. Infants with "normalized DDH" had achieved a stable clinical examination with an ultrasound revealing no signs of either hip instability or acetabular dysplasia. We excluded infants with persistently abnormal ultrasonographic indices, clinical examinations, or both by 6 months of age, including those requiring surgical reduction. Anteroposterior pelvic radiographs at approximately 6 and 12 months of age were then evaluated for evidence of residual radiographic acetabular dysplasia. Radiation effective dose was calculated using PCXMC software.
Results:
We identified 115 infants with DDH who had achieved both normal ultrasonographic and clinical examinations at 3.1±1.1 months of age. At the age of 6.6±0.8 months, 17% of all infants demonstrated radiographic signs of acetabular dysplasia. Of infants left untreated (n=106), 33% had dysplasia on subsequent radiographs at 12.5±1.2 months of age. No significant differences were evident in either the 6- or 12-month rates of dysplasia between infants successfully treated with a Pavlik harness and infants normalizing without treatment but with a history of risk factors (P>0.05). The radiation effective dose was <0.01 mSv for the combined 6- and 12-month single-view anteroposterior radiographs of the pelvis.
Conclusions:
The notable incidences of radiographic dysplasia after previous DDH normalization in our study cohort appear to outweigh the risks of radiation exposure. Our findings may warrant radiographic follow-up in this population of infants through at least walking age to allow timely diagnosis and early intervention of residual acetabular dysplasia.
Level Of Evidence:
Level IV-retrospective case series.
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