Developmental dysplasia of the hip (DDH) is a common disorder affecting infants and young children. In this condition, there is a disruption in the normal relationship between the head of the femur (thigh bone) and the acetabulum (hip socket). DDH can affect one or both hips. It can be mild to severe. In mild cases called unstable hip dysplasia, the hip is in the joint but easily dislocated. More involved cases are partially dislocated or completely dislocated. A partial dislocation is called a subluxation.
Sixty years ago, Dr. Arnold Pavlik designed a special harness for the treatment of developmental dysplasia of the hip. It is still in use today as the number one choice for this condition in babies. The harness holds the child’s hips in a flexed and abducted (legs apart) position. This places the round head of the femur (thigh bone) right in the hip socket. The contact and pressure help form a deeper, more stable hip joint. At the same time, hip muscles are stretched, which reduces the pull on the hips and helps keep the femoral head in the acetabulum (hip socket).
The harness is most effective when used early on in the child’s life (e.g., the first three months following diagnosis). For the parents/family who know their child was born with a hip dislocation, treatment is usually effective in the first three weeks. It must be worn everyday all day.
Studies have shown some factors to be predictive of treatment failure with the harness. Those factors include putting the harness on wrong, not using the harness as described, positive family history of developmental dysplasia of the hip, and breech position (feet or bottom first) at birth. Starting treatment too late is also a risk factor. And children whose hips don’t reduce or relocate at the time of diagnosis are less likely to be helped by the harness.
A recent study comparing results using a Pavlik harness between children with unilateral (one hip) involvement versus bilateral (both hips affected) showed no difference in results. Successful results were achieved in both groups on average between three and four months.
The authors of that study concluded that bilateral hip dislocations associated with developmental dysplasia of the hip does not increase the risk of treatment failure using the Pavlik harness. Families can expect to use the harness for a period of time that is equal to two times the age of the child. For example, if the child is two months old, then treatment will likely last four months. Age used in the calculation is the age of the child when the harness was first applied. There’s some evidence that treatment takes a little longer when both hips are dislocated, but further study is needed to confirm this idea.