Hip dysplasia (HD) is a well-known inherited orthopedic condition which can affect mostly large breed dogs and lead to osteoarthritis causing pain and diminished quality of life if not controlled or treated.
Many surgical techniques and conservative treatments have been described in dogs with already established hip dysplasia but most of the times they are invasive, expensive or not effective. The only surgical minimal invasive procedure that can prevent hip dysplasia in early age before it actually happens is called Juvenile Pubic Symphysiodesis (JPS) and can be performed only in dogs of 3 to 4 months of age when the growth plates of their skeleton are still open. There is about a 85% chance that predisposed to HD dogs will benefit from having the procedure done strictly at this age (12 -16 weeks).
How the JPS surgery works
The illustration of the pelvis (below) is viewed from a dog’s rear end. The growth plate (growth center) of the pubic bone (arrow) is destroyed with electrocautery. Therefore, this portion of the pelvis no longer grows. The remaining parts of the pelvis grow, which rotates the acetabula (sockets of the hips) over the femoral head (ball of the hip), providing a better coverage and minimizing the effects of HD.
Identification of candidates for the JPS surgery
As most dogs at this age do not have any clinical signs of hip dysplasia the only accurate method that can early detect it is radiograph screening with a distraction device (PennHip method) in combination with orthopedic examination under short general anesthesia. This device permits the accurate measurement of maximal hip laxity – the inherent distance the ball (femoral head) can be displaced from the hip socket (acetabula) and is called Distraction Index (DI). The distraction index range can vary among different dog breeds but generally DI higher than 0.3 and lower than 0.5 reveal good surgical candidates for JPS.