What is the most appropriate next step in managing a 2-month-old female infant with asymmetric skin creases and apparent leg length discrepancy, but negative Barlow and Ortolani maneuvers, during a routine newborn examination?

From the Guidelines

The most appropriate next step in management for this 2-month-old girl is ultrasonography of the hips (option D). The physical examination findings of asymmetric thigh creases (4 on the left, 1 on the right) and apparent limb length discrepancy when the knees are flexed strongly suggest developmental dysplasia of the hip (DDH), despite negative Barlow and Ortolani maneuvers. Ultrasonography is the preferred imaging modality for infants under 4-6 months of age because their hip joints are still largely cartilaginous and not well visualized on plain radiographs, as noted in the American College of Radiology guidelines 1. Early detection and treatment of DDH is crucial to prevent complications like avascular necrosis, early osteoarthritis, and gait abnormalities. While the negative Barlow and Ortolani tests might suggest stability, these tests become less sensitive as infants age beyond the newborn period, and the physical findings of asymmetric skin folds and limb length discrepancy warrant further evaluation with imaging rather than just reassurance or delayed follow-up, as supported by the studies on DDH diagnosis and management 1. The use of ultrasonography in this context is further justified by its ability to detect hip instability and guide appropriate treatment, reducing the risk of overtreatment and iatrogenic complications 1. Given the potential long-term consequences of untreated DDH, including the need for total hip arthroplasty in up to a third of cases by the age of 60 1, prompt and accurate diagnosis through ultrasonography is essential for optimizing outcomes in this patient.

From the Research

Diagnosis and Management of Developmental Dysplasia of the Hip

• The patient's physical examination shows an alert infant who is moving all extremities equally, with 4 skin creases along the inner left thigh and 1 on the right, and the left knee appears to be inferior to the right knee when supine with the knees flexed 2, 3.
• The Barlow and Ortolani maneuvers are negative, which suggests that the hip is not dislocated, but it does not rule out the possibility of developmental dysplasia of the hip (DDH) 4.
• According to the American Academy of Pediatrics and the American Academy of Orthopaedic Surgeons, hip ultrasonography is recommended for early detection of DDH in infants 2.
• Ultrasonography of the hips is a non-invasive and effective method for diagnosing DDH, especially in infants under 6 months of age 3, 5.
• The most appropriate next step in management of this patient would be to perform ultrasonography of the hips to assess for any signs of DDH, such as acetabular dysplasia or femoral head subluxation 3, 5.

Imaging Modalities for DDH

• Ultrasonography is the preferred imaging modality for diagnosing DDH in infants under 6 months of age, due to its high sensitivity and specificity 3, 5.
• MRI can be used as an adjunct to ultrasonography, especially in older infants and children, to provide more detailed images of the hip joint and surrounding structures 4, 5.
• X-ray examinations have a limited role in the diagnosis of DDH, but can be used for follow-up examinations after treatment and for diagnosing secondary dysplasia 3.

Recommendations for This Patient

• Based on the patient's age and physical examination findings, ultrasonography of the hips is the most appropriate next step in management 3, 5.
• If the ultrasonography results are abnormal, further evaluation and treatment may be necessary to prevent long-term complications of DDH 3, 5.