Significance of Asymmetry of Groin and Thigh Skin Creases in Developmental Dysplasia of the Hip Revisited: Results of a Comparative Study.

Background: No high level of scientific evidence exists about the use of asymmetry of skin creases (ASC) on the groin and thigh regions in diagnosing developmental dysplasia of the hip. The aim of this comparative study was to revisit whether or not ASC was a significant clinical finding in developmental dysplasia of the hip.

Methods: This was retrospective analysis of a prospectively collected data. Control group was composed of 1000 consecutive healthy infants (mean age, 46.7 d) whose both hips were considered Graf type I (normal). Study group (SG) was composed of 246 consecutive patients (mean age, 96.5 d) whose treatments by abduction bracing were initiated due to unilateral or bilateral Graf type IIa(-) and worse hips.

Results: SG included 178 patients with bilateral or unilateral dysplastic hips [Graf type IIa(-), IIb, IIc] and 68 patients with at least 1 decentered hip (Graf type D, III, IV). ASC was seen in 63 of 101 patients (63%) having positive clinical finding(s). The rates of both ASC alone (P<0.001; odds ratio, 3.46) and ASC total (ASC with and without additional findings) (P<0.0001; odds ratio, 7.48) were significantly higher in SG than in control group. ASC was the only clinical finding in 31 patients and 24 of these 31 patients (77%) had unilateral or bilateral dysplastic hips. Sensitivity and specificity of ASC alone were 12.60% and 96.00%, respectively. ASC was accompanied by other clinical findings (mostly Galeazzi sign and limitation of abduction) in 32 patients and 23 of these 32 patients (72%) had at least 1 decentered hip. Sensitivity and specificity of ASC total were 25.61% and 95.60%, respectively.

Conclusions: ASC is a significant finding, as there is considerable increased risk of having dysplastic or decentered hips in infants having such a finding alone or associated with other findings. ASC alone is more commonly seen in patients with dysplastic hip(s) whereas ASC is mostly accompanied with other clinical finding(s) in patients with decentered hip(s). This study shows that, ASC can be introduced as a risk factor in selected newborn hip screening programs.

Level Of Evidence: Level II-diagnostic study.