Asymmetrical thigh creases or isolated thigh crease may be a false positive sign with low predictive value in the diagnosis of developmental dysplasia of the hip in infants: a prospective cohort study of 117 patients.

Abstract

The clinical importance of asymmetrical thigh creases in the diagnosis of developmental dysplasia of the hip (DDH) in infants remains controversial. The aim of this study is to investigate the association of asymmetrical skinfolds of the thigh as the only clinical finding with the DDH in infants. One hundred and thirty-four infants between January 2010 and December 2015 were referred to our clinics for DDH with the only clinical sign being asymmetrical or isolated thigh creases and met the inclusion criteria of the study. Patients with another clinical sign for DDH in our initial evaluation, those infants suspicious for syndrome and those older than 6 months were excluded. Finally, 117 patients had undergone clinical and ultrasound evaluation and were included to statistical analysis. There were 82 females and 35 males, with mean age of 2.2 months old. In 96 of the 117 infants (82.1%), there were provocative skin creases in the opposite thigh after a little pressure of the thigh by the examiner during the evaluation. Three of the babies (3.1%) with provocative skin creases and 1 (4.8%) with true isolated thigh crease had immature hips in ultrasonography. Positive predictive value for DDH of an isolated or asymmetrical thigh crease was 4.55% (95% CI 0.83-21.36%), and negative predictive value was 96.97% (95% CI 94.75-98.27%). Sensitivity of skinfold asymmetry found to be 25% (95% CI 0.63-80.59%), and specificity was 82.05% (95% CI 73.88-88.53%) for DDH. The positive predictive value of asymmetrical or isolated thigh creases for DDH in infants was found to be low, as the majority of hips with normal clinical examination and asymmetry in thigh skinfolds seemed to be normal. Moreover, in-depth evaluation of the patients could highlight new provocative thigh creases in the opposite thigh, which could limit the referrals to expert physicians to exclude DDH. Level III.