O3260: The Bladder is Out But is the Hip In? Hip Dysplasia in Infants with Classic Bladder Exstrophy

Background: Bladder exstrophy is a rare disorder involving the urinary, reproductive, and musculoskeletal systems. Published studies suggest that individuals with bladder exstrophy have an increased incidence of hip dysplasia, but these studies included a wide range of ages and patients with both classic bladder exstrophy (CBE) and cloacal exstrophy (CE). Since CE is often accompanied by neurological conditions (such as myelomeningocele and tethered cord) that may themselves cause hip dysplasia, it is not clear if CBE is independently associated with hip dysplasia. This study therefore reports the prevalence of hip dysplasia in infants and toddlers with classic bladder exstrophy (CBE).

Methods: A retrospective database of patients with CBE aged 0-17 at a tertiary care pediatric hospital from January 2014 to June 2023 was queried for infants with CBE who had hip ultrasounds (US) within the first 6 months of life. Historical and imaging records for these patients were then reviewed. Patients with incomplete records or imaging studies, and those with a diagnosis of CE or epispadias were excluded.

Results: Forty-six patients with CBE were identified; 29 (63%) had an US. Of these, ten (35%) were female. Nineteen patients (65%) had normal US findings. Nine (31%) had mild dysplasia on US (α angle 43-60° and/or femoral coverage < 50%). One male patient had bilateral dislocated hips, which underwent staged open reductions.

Of the 9 patients with mild dysplasia, the dysplasia was bilateral in 7 and unilateral in 2 (1 right and 1 left). Eight of these resolved with observation. One patient was successfully treated with Pavlik Harness.

Of the 29 patients with US studies, nine had radiographic follow-up past the age of 3 years (range 36-68 months). These included five patients with mild dysplasia and the single patient with bilateral dislocated hips. The most recent radiographs for these patients showed all hips to be IHDI grade I and no residual dysplasia, with a mean acetabular index of 13.3 (range 5-23).

Conclusion: Infants and children with CBE have a high rate of hip dysplasia. Most of these correct with observation or nonoperative treatment, and the short-term outcome is good. Infants with CBE should be screened with US and any dysplasia treated according to established protocols. This is the first study reporting the prevalence and treatment of hip dysplasia in infants with CBE (excluding CE). It provides insight and guidance in the treatment of this rare, complex condition.