A 4-month-old infant screening suggests possible right hip dislocation. Which findings are MOST consistent with this diagnosis?

A 4-month-old infant screening suggests possible right hip dislocation. Which findings are MOST consistent with this diagnosis?

• A. Pelvic obliquity, apparent pain on movement of the right hip, and decreased hip abduction on the left side
• B. Asymmetrical gluteal folds, femoral telescoping and limited hip abduction on the right side
• C. Decreased active movement of the right hip, increased femoral neck retroversion, and atrophy of the gluteus maximus on the right side
• D. Hip flexion contracture on the right side, apparent leg length discrepancy, and inability to tolerate supported sitting

Answer: (B)

In infants, the most telling signs of developmental dysplasia of the hip are related to instability of the hip joint. The best fit shows the right hip dislocation through three linked findings: asymmetrical gluteal folds, which occur because the leg is not seated evenly in the socket and creates unequal skin folds; femoral telescoping, where gentle vertical pressure on the thigh causes noticeable movement of the femur within the hip region due to poor containment; and limited abduction on the affected side, since the displaced femoral head blocks smooth outward movement of the thigh. Other signs listed are less typical or less specific for a dislocated hip in a 4-month-old. Pain on movement isn’t a common presentation in infants, and signs like decreased active movement, muscle atrophy, or a hip flexion contracture aren’t as characteristic early on. Retroversion of the femoral neck isn’t something assessed clinically in this age as a primary diagnostic sign, and a leg length discrepancy or difficulty sitting unsupported are less direct indicators at this stage.

In infants, the most telling signs of developmental dysplasia of the hip are related to instability of the hip joint. The best fit shows the right hip dislocation through three linked findings: asymmetrical gluteal folds, which occur because the leg is not seated evenly in the socket and creates unequal skin folds; femoral telescoping, where gentle vertical pressure on the thigh causes noticeable movement of the femur within the hip region due to poor containment; and limited abduction on the affected side, since the displaced femoral head blocks smooth outward movement of the thigh.

Other signs listed are less typical or less specific for a dislocated hip in a 4-month-old. Pain on movement isn’t a common presentation in infants, and signs like decreased active movement, muscle atrophy, or a hip flexion contracture aren’t as characteristic early on. Retroversion of the femoral neck isn’t something assessed clinically in this age as a primary diagnostic sign, and a leg length discrepancy or difficulty sitting unsupported are less direct indicators at this stage.