Maintaining the hips in flexion and abduction posture is a common recommendation to facilitate hip maturation in infants. Double diapering helps to maintain a baby’s hips in flexion and abduction posture, but the efficacy of double diapers in hip development has never been verified. We investigated whether double diapering results in greater improvement of the alpha angle in the first months of life.
This prospective randomised control study enrolled newborns with Graf type IIa hips. Babies were assigned to the double-diaper or single-diaper group. Parents were instructed on proper hip positioning, except for diapering. Change in the alpha angle from newborn to 1 month after birth, rate of improvement to bilateral Graf type I hips in 1 month, and number of ultrasound examinations and orthopaedic clinic visits in the first year were compared between the two groups. For babies with bilateral IIa hips, we used the averaged data from both hips, and for babies with unilateral IIa hips, we used the data from the IIa hips.
Seventy newborns with 102 type IIa hips were included from January to December 2017. They were allocated to the double-diaper group (N=33) and single-diaper group (N=37). With a comparable sex ratio, gestational age, and newborn alpha angle, the double-diaper group had a greater increase of alpha angles in 1 month than the single-diaper group (+7.9° vs. +5.2°, t-test, p=0.011). Twenty-eight babies in the double-diaper group (84.8%) and 20 babies in the single-diaper group (54.1%) improved to having bilateral Graf type I hips (chi-square test, p=0.006). Subsequent clinical visits and hip ultrasounds before 1 year were significantly reduced in the double-diaper group.
Our results support double diapering for enhancing hip maturation in babies with Graf type IIa hips. The amount of improvement may not indicate double diapering as a treatment for hip dysplasia, but its effects in immature hips are noteworthy in reducing further clinical and ultrasound follow-ups.