Incidence of hip problems in developmental central hypotonia: A scoping review

Children with rare genetic conditions often have hypotonia or low muscle tone and delayed motor skills like standing and walking. We know that children with cerebral palsy (CP) with limited standing and walking abilities are at increased risk for hip subluxation or dislocation (where the hips are partly or fully out of position), whether they have high or low muscle tone. Hip surveillance (a program of regular orthopaedic assessments and x-rays) helps to recognize the early signs of hip problems and makes sure children get the best interventions at the right time. However, children with hypotonia who do not have a CP diagnosis often do not receive hip surveillance.

We searched for journal articles or book chapters describing children or adults with rare genetic conditions (like Prader-Willi, Kabuki, Joubert, 49, XXXXY, PURA, as well as other rare syndromes) who were reported to have both hypotonia and hip problems.

We found reports of 544 children and adults aged 1 month to 63 years with hypotonia and hip problems due to rare genetic or undiagnosed conditions. Some had differences in hip shape when they were born, and hip problems also got worse over time. We found that children with hypotonia have a much higher rate of hip problems than children with normal muscle tone, and these problems are often missed by typical infant screening programs. Some children dislocate their hips after they start walking, and older children and adults can also develop painful dislocated hips.