Abstract
Purpose
To clarify the true association with pathological DDH and ASC (asymmetrical skin crease).
Method
Between 1st January 1995 and 31st December 2015 all paediatric referrals with suspected hip instability were assessed in a one-stop DDH clinic. All patients had clinical and sonographic assessment with results prospectively recorded onto a database.
Result
Over this 21-year period, 103 cases were referred with ASC. Seventy were female and 33 male. The age distribution at initial assessment was bimodal with peaks at 3 and 9 months. Eighty-three cases (81% ) were referred with ASC, but the hip joints were normal on both clinical examination and sonography. Eighteen cases (17% ) were referred with ASC but had an additional risk factor. This group also had normal hips on both clinical examination and sonography. Of the 103 cases, only two had pathological DDH. Both were female and aged 3 and 10 months respectively. They had ASC, but in addition had unilateral limitation of hip abduction, a Galeazzi positive sign and a leg length discrepancy. Radiological assessment diagnosed unilateral irreducible hip dislocations in both cases. Statistical analysis calculated an overall sensitivity for ASC of 100% and a PPV of 1.94% .
Conclusion
Public Health England NIPE guidelines state that ASC are a ‘screen positive sign’ and should be referred for expert assessment of the hip joints to exclude DDH. This study confirms the opinions of experts and systemic reviews that isolated ASC is an unreliable clinical sign in the diagnosis of pathological DDH. If the hip joint is clinically normal it is highly unlikely that there will be an association with pathological DDH. Routine radiological and sonographic imaging of the hip joints is unnecessary if there is no limitation of hip abduction and normal leg lengths (negative Galeazzi). National guidelines should reflect this.
