METHODS: This was a retrospective study of children with CMT who had at least one pelvic radiograph between 2000 and 2020. Reimer's migration percentage, acetabular index and lateral center edge angle were used to identify hip dysplasia.
RESULTS: A total of 178 children were included with a median age of 6.4 (IQR 3.4-11.3) years at CMT diagnosis. First pelvic radiographs were performed at a median age of 8.0 (IQR 4.6-12.2) years and 64 (35.8%) had hip dysplasia, of which 20 normalized over time. Repeat radiographs were done in 96/178 children (53.9%), and six children with originally normal radiographs developed later radiographic hip dysplasia. At the time of last follow up, 50/178 children (28.1%) had hip dysplasia and 17/178 children (9.6%) required surgical intervention. The frequency of hip dysplasia in specific CMT subtypes was: 28/100 in CMT1A, 5/7 in Dejerine-Sottas disease, 3/10 in CMT2A, and 4/4 in TRPV4-related CMT.
INTERPRETATION: The prevalence of hip dysplasia in children with CMT in this cohort was estimated to be between 9.6% and 28.1%. Serial imaging is important to monitor outcomes into adulthood. Specific CMT subtypes were more likely to be associated with hip dysplasia.