Background: The aim of this study was to assess the accuracy of clinical screening examination in newborns with dislocated hips compared with ultrasound scan (USS).
Methods: Newborns, up to 3 months of age, with confirmed hip dislocations on USS were prospectively enrolled in a multinational observational study. Data from 2010 to 2016 were reviewed to determine pretreatment clinical examination findings of the treating orthopaedic surgeon as well as baseline ultrasound indices of developmental dysplasia of the hip (DDH). All infants had been referred to specialist centres with expertise in DDH, due to abnormal birth examination or risk factor.
Results: The median age of the study population was 2.3 weeks and 84% of patients were female. Of the total 515 USS-confirmed dislocated hips included in the study, 71 (13.8%) were incorrectly felt to be reduced on clinical examination by the treating orthopaedist (P<0.001). Full hip abduction was documented in 106 hips. Of the hips correctly identified as dislocated, 322 hips were further analyzed based on clinical reducibility. Thirty-three of 322 (10.2%) were incorrectly thought to be reducible when in fact they were irreducible or vice versa.
Conclusions: Expert examiners missed a significant number of frankly dislocated hips on clinical examination and their ability to classify hips based on clinical reducibility was only moderately accurate. This study provides evidence that, even in experienced hands, physical examination findings in DDH are often too subtle to elicit clinically in the first few months of life. This may explain the persistent and measurable rate of late presenting dislocations in countries with screening programmes reliant on clinical examination.
Level of evidence: Level 1-testing of previously developed diagnostic criteria in series of consecutive patients (with universally applied reference "gold" standard).