This surgery is performed on young puppies before five months of age, so it is generally done as a preventive procedure before it is known if the puppy will indeed have dysplastic hips but after hip laxity has been detected. The pubic symphysis (purple line) is the cartilage seam connecting the right side of the pelvis to the left side. As an individual matures, this cartilage converts to bone and the two halves of the pelvis fuse permanently.
.
This surgery prematurely seals the symphysis, which decreases the growth rate of the ventral (bottom) part of the hip compare to the dorsal (top) part. Hence results in rotation (purple arrows) of the developing hip sockets and improve femoral head coverage
.
The correction window (3-5 months of age) is very narrow for this procedure so if a puppy is a predisposed breed, it may be worth getting screening radiographs around 4 months of age even though no physical discomfort has developed. It may be worth having this preventive procedure while the puppy is still at an age to benefit from it.