Imaging of the Unstable Hip
Limited evidence supports that the practitioner might obtain an ultrasound in infants less than 6 weeks of age with a positive instability examination to guide the decision to initiate brace treatment.

Rationale

If faced with an unstable hip examination, there is limited evidence to support the use of sequential ultrasound to aid in determining when to initiate brace treatment for infants up to 8 weeks of age. Fewer children may undergo brace treatment with no difference in the occurrence of late dysplasia. One moderate quality study (Elbourne 2002) met the inclusion criteria and compared infants with clinical hip instability who were evaluated with ultrasoniographic hip examination or clinical assessment alone. This study evaluated outcomes in a total of 629 infants across 33 centers (total patients in both evaluation groups). There was no statistically significant difference in outcomes for the need for surgical treatment for developmental hip dysplasia, but fewer children in the group which was assessed using ultrasonography required abduction splinting in the first 2 years than those in the group which received a clinical assessment alone. Initially this study was graded as high strength but was downgraded to moderate strength because the rate of splint treatment was not the primary outcome. Additionally, it is unclear that all subjects were normal infants with DDH and no confounding diagnoses.

In this study, infants with hips that had minor instability were not immediately treated. Experienced doctors performed the clinical examinations. Even though there is even distribution between the groups in terms of number of history of instability, subgroup analysis of dislocated versus dysplastic hip results were not available.

RISKS AND HARMS
There is a potential delay of necessary treatment.

2022 UPDATE ADDITIONAL EVIDENCE
1. Burnett, M., Rawlings, E. L., Reddan, T. An audit of referral time frames for ultrasound screening of developmental hip dysplasia in neonates with a normal antenatal clinical examination. Sonography 2018; 2: 61-66.

2. Lussier, E. C., Sun, Y. T., Chen, H. W., Chang, T. Y., Chang, C. H. Ultrasound screening for developmental dysplasia of the hip after 4 weeks increases exam accuracy and decreases follow-up visits. Pediatr Neonatol 2019; 3: 270-277