I'm finding out our son with his developmental dysplasia of the hip (DDH) is a rare bird. Everything I've seen says girls outnumber boys with this problem. Is there any proof that boys have a better or worse result with treatment?

About 85 percent of the infants affected by DDH are indeed females. That leaves a smaller 15 percent to the males. It's not clear why there is this gender difference. For the most part it looks like DDH occurs as a result of outside factors. In other words, although it can develop in utero, it can also occur during the first year of life.

Breech delivery, large babies, and multiple births seem to be some of the risk factors. Family history and first pregnancies are also factors.

As far as results go there doesn't appear to be any difference in success or failure rates based on gender. The condition of the hip cartilage seems to be the clearest predictive factor. If the covering or roof of the hip socket has started to harden into fibrocartilage, then the prognosis is not as good. The long-term results are better if the cartilage is the softer hyaline cartilage.