There’s new information that children who had a totally normal hip may deteriorate if they also had a dislocated hip on the opposite side.
A report from Oslo, Norway followed 48 patients for fifty years after closed reduction and cast immobilization for a dislocated hip when only one side was affected. The other side was perfectly normal by all available x-ray measurements at the time of initial treatment. In these patients, the previously normal hip became dysplastic in 17% of patients, or approximately one out of six. That’s a pretty high number when the hips were normal as infants. The ages at time of initial treatment was from 4 months to 5 years.
There are probably a lot of lessons in this long-term study. It’s unlikely that the treatment caused the other hip to become dysplastic. This means that there are underlying conditions that may cause hip dysplasia to develop after birth. Another lesson is that not all dislocated hips occur at birth. It’s long been known that late dislocations can occur. Some have occurred after normal ultrasound studies at six weeks and this is another reason why dislocations may be found at walking age instead of at birth. Another lesson is that parents and doctors can never stop worrying about the opposite hip even when it looks normal. There is a tendency to stop seeing the doctor after things have been going well for a few years. Now, it seems that follow-up x-rays are needed until skeletal maturity if there was a complete dislocation on one side or even on both sides. This also explains why some hips that were successfully treated may worsen with age even though there doesn’t seem to be any reason for that to happen.
Fortunately, most children with mild hip dysplasia improve naturally or respond to non-surgical treatment. Also, the large majority of children who are treated for hip dislocation never have any more problems with that hip or the other hip. We recommend that parents remain optimistic because most of the time things go well. However, parents of children with complete hip dislocations should also remain vigilant for any signs of deterioration of the treated hip, or signs of problems with the opposite hip until maturity.
Terjesen T. Dysplasia of the contralateral hip in patients with unilateral late-detected congenital dislocation of the hip: 50 years’ follow-up of 48 patients. Bone Joint J. 2014 Sep;96-B(9):1161-6.