Clinical significance of asymmetric skin folds in the medial thigh for the infantile screening of developmental dysplasia of the hip

Background The presence of asymmetric skin folds in the medial thigh (ASM) is often used as one of the screening items for developmental dysplasia of the hip (DDH). However, few studies have evaluated the clinical relevance of ASM in DDH. Methods We reviewed the data of 584 infants aged 4–12 months who were referred to our institute because of suspicious findings in periodic infantile DDH screenings. The reasons for referral were classified into ASM, gluteal asymmetry, limb-length discrepancy, limitation of hip abduction, and click/clunk of the hip. A simple radiograph and hip examination including stability assessment were evaluated in all the infants by an experienced pediatric orthopedic surgeon. Results Most of the referred infants presented with ASM only (78.4%, 458/584), but none of them were diagnosed with DDH. On the other hand, about 18.3% of infants referred for other reason(s) were diagnosed with DDH. Conclusion Although the presence of ASM was the most common reason for referral, it had little clinical significance as a screening item for DDH in the infants aged 4–12 months. Therefore, ASM alone is not a clinical indicator of DDH.