Objectives: To determine among general practitioners (GPs) the most common clinical findings that raised concern for developmental dysplasia of the hip (DDH) and necessitated an orthopedic outpatient referral. In addition, we assessed the sensitivity and specificity of the most common of these clinical findings.
Study design: We performed a multicenter retrospective review of all referrals by GPs to local orthopedic outpatient departments for DDH over a 12-month period. All patients had undergone pelvic radiographs, and the acetabular index (AI) was measured. The AI was used as a reference test to assess the accuracy of the clinical examination in diagnosing DDH. Sensitivity and specificity of each clinical sign was calculated.
Results: Twenty-six of 174 (14.9%) referred patients were diagnosed with DDH, defined as an AI score > 30. The most common indication for referral, per the GP letter was asymmetrical skin folds (97 patients, 45.8%), followed by hip click (42 patients, 19.8%), and limb shortening (34 patients, 16%). Sensitivities and specificities, respectively, among findings were asymmetric skin folds 46.2% (95% CI 26.6%-66.6%) and 42.6% (95% CI 34.5%-51.0%), hip click 23.1% (95% CI 9.0%-43.6%) and 75.7% (95% CI 67.9%-82.3%), limb shortening 30.8% (95% CI 14.3%-51.8%) and 82.4% (75.3%-88.2%), and reduced abduction 19.2% (95% CI 6.6%-39.4%) and 91.9% (95% CI 86.3%-95.7%). Using logistic regression analysis, no clinical sign was found to be a statistically significant indicator of an abnormal AI.
Conclusions: Clinical examination by GPs does not reliably detect radiographically-defined DDH. None of the clinical findings by the GP showed an acceptable level of sensitivity. Absence of reduced abduction and limb shortening are relevant negatives given the high level of specificity of these signs.
Keywords: DDH; abduction; acetabular index; clicky hips; examination; hip; referrals.
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