The examiner abducts or moves the infant’s legs apart. If the hip is dislocated, during this motion, the head of the femur slides over the rim of cartilage that is around the hip socket. There is a click or clunking sensation as the head of the femur slips back into the socket. This is called a positive Ortolani’s Maneuver.
In this study, the results of an Ortolani test are compared to findings seen on ultrasound (US). US is an imaging study that has been shown effective in detecting hip dislocations from hip dysplasia.
Four hundred (400) infants were included in this study. All of the babies had been diagnosed with developmental dislocation of the hip. Forty-five (45) patients were in Group 1 (Ortolani positive). Twenty-four (24) patients in group 2 were Ortolani negative but had a positive US for hip dislocation.
After careful study and comparison, the researchers found that age was the main difference between these two groups. The Ortolani test appears to be more reliable with younger children (less than one month old).
In older children, the cartilage around the hip is deformed. The expected clunk may not be present on testing despite the fact that the hip is really dislocated (Ortolani negative). Or the cartilage forms a second false socket trying to stabilize itself. The physician may feel a click or clunk as the hip slips into the false socket.
The authors conclude that the clunk is always a sign of a dislocated hip (positive Ortolani’s test). However, a positive Ortolani’s does not necessarily mean the hip has relocated back into the socket. Imaging studies must be done to know for sure. This second step is important to prevent treating a hip that can’t be fixed without surgery.