Objective: To determine the contribution of long-bone radiographs to the diagnosis and management of newborn infants at risk for congenital syphilis.
Design: Historical cohort.
Setting: Three large hospitals in Houston, Tex.
Patients: Eight hundred fifty-three live born infants who were evaluated for the presence of congenital syphilis.
Intervention: Long-bone radiographs done as part of the diagnostic evaluation for the presence of congenital syphilis.
Main outcome measure: Changes in diagnostic classification or management decisions that were based on radiographic findings in the long bones.
Results: For 450 infants, radiographic results did not affect management because clinical or historical factors were present that dictated treatment: 26 infants had clinical symptoms of congenital syphilis (65%  had abnormalities on radiographs); and 424 infants were born to mothers who were untreated or reinfected (5.9%  had abnormalities on radiographs). All of these infants required a full course of therapy regardless of radiologic findings. Born to mothers with possibly inadequate therapy (according to 1993 Centers for Disease Control and Prevention guidelines), 237 asymptomatic newborn infants were candidates for a single injection of penicillin G benzathine if the results of their evaluations were normal; of these, 2 (0.8%) had abnormal radiographic findings. Of the 166 infants born to adequately treated mothers with appropriately falling serologic titer levels, 1 (0.6%) had abnormal radiographic findings (P=.99 between groups). The results of the long-bone radiographs did not alter management for any of the 853 infants who were evaluated for congenital syphilis.
Conclusions: Long-bone radiographic findings, often abnormal in symptomatic infants, do not differentiate between active infection and past infection. The use of long-bone radiographs should be reconsidered in the routine evaluation of infants for congenital syphilis.