Parents and doctors worry that hip dysplasia may not be “cured” after the initial treatment even though everything seems normal when treatment is stopped. Unfortunately, hip dysplasia can reappear even though the hips seemed normal at the end of initial treatment. The reasons for this are unknown, but this is a reason why some doctors insist on prolonged bracing even when the x-ray or ultrasound seems normal. This is also why most doctors want your child to return months or years after successful treatment because sometimes hips deteriorate during growth.
Two scientific papers shed light on this problem during early childhood. The first paper was published in 2010 and a member of the IHDI Medical Advisory Board was the senior author. [https://www.ncbi.nlm.nih.gov/pubmed/19915881] Scott Mubarak, MD and his colleagues studied breech babies that had a normal newborn exam and a normal hip ultrasound at six weeks of age. Instead of releasing them from care, the children were re-examined with x-rays at four to six months of age. Surprisingly, approximately one in four had developed dysplasia that was treated with bracing. Those children would have gone untreated, and perhaps would have developed early hip arthritis if they had not returned for a final visit.
A more recent study was published this month from Children’s Hospital of Philadelphia [https://www.ncbi.nlm.nih.gov/pubmed/25333906]. The authors of this study re-evaluated 115 infants with hip dysplasia who were treated with the Pavlik harness and achieved normal ultrasound and clinical examinations at 3 months of age. Treatment was stopped at that time because the exam and ultrasound were normal. However, at one year of age one third of the children had re-developed mild dysplasia on a follow-up x-ray.
These two studies and others like them show that it is important to continue seeing your doctor even when things seem to be going well. In these younger children, it is possible to nip the problem early with night time bracing to help the hips recover if hip dysplasia returns. The authors of the second paper also evaluated the amount of x-ray exposure during follow-up evaluation. They determined that modern x-rays have very low dose exposure and the total of two pelvis x-rays was less than 0.01 mSv. This is about ten times less than a standard chest x-ray and about the same amount that people get from natural radiation during a two hour airplane flight. In other words, the benefits of a follow-up x-ray greatly outweigh the tiny amount of radiation to the child.
In summary, there is still a long way to go to understand why hips that were normal can have a return of mild dysplasia. Also, these reports emphasize the need to go back to the doctor for a check-up even though everything seemed to be normal after treatment.