Abstract
The aim was to assess the value of the GP 6–8 week hip examination.
In a 15-year prospective observational longitudinal cohort study, every infant referred by the GP with suspected pathological developmental dysplasia of the hip (DDH) had their hip joints clinically and sonographically examined in a specialist hip screening clinic. Graf Type IV and dislocated hips were classified as pathological. Screening failures were defined as those who had not been identified by the 6–8 week check and presented with late instability. Secondary univariate and multivariable analysis was performed to determine which clinical findings are predictive of instability.
64,518 infants underwent the 6–8 week GP check. Of 176 referrals, 5 had pathological hips. 13 screening failures, presented between the ages of 17 and 80 weeks. The 6–8 week check has a sensitivity of 28% and a specificity of 99.7%.
Univariate analysis revealed positive Ortolani tests and patients referred as ‘unstable hip’ to be significant predictors of hip pathology. Clicky hips, asymmetric skin creases, and leg length inequality were not predictive of pathological hips. A multivariable model showed a positive Ortolani test to be the sole independent predictor of instability at 6–8 weeks.
This is the first attempt to test the validity of the 6–8 week GP clinical hip check. A low rate of hip pathology was identified. The high rate of false negatives raises questions about the value of screening at this age. At 6–8 weeks, clinical signs of hip instability are unreliable as hips become irreducible and stiff.
Based on our findings, we recommend that at 6–8 weeks, referrals are only made if the Ortolani test is positive. We advocate the reintroduction of the 8-month check, including an assessment for limited hip abduction, which may improve the detection rate of those missed by initial screening.
