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.
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 strength study showed fewer children in the ultrasound group had abduction splinting in the first two years than did those in the no ultrasound group (0•78; 0•65–0•94; p=0•01). 19 The primary outcome was the appearance on hip radiographs by two years. Secondary outcomes included surgical treatment, abduction splinting, level of mobility, resource use, and costs. Analysis was by intention to treat. Protocol compliance was high, and radiographic information was available for 91% of children by 12–14 months and 85% by 2 years. By age 2 years, subluxation, dislocation, or acetabular dysplasia were identified by radiography on one or both hips of 21 children in each of the groups (relative risk 1•00; 95% CI 0•56–1•80).
Surgical treatment was required by 21 infants in the ultrasound group (6•7%) and 25 (7•9%) in the no-ultrasound group (0•84; 0•48–1•47). One child from the ultrasound group and four from the no-ultrasound group were not walking by 2 years (0•25; 0•03–2•53; p=0•37). 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.
There is a potential delay of necessary treatment.