Surgery STAT: Diagnosis, treatment of canine hip dysplasia

Juvenile pubic symphysiodesis (JPS) surgery is a prophylactic procedure performed in puppies 10 to 20 weeks of age that have been diagnosed with hip dysplasia as discussed in last month's column. This technique was developed as our ability to diagnose hip dysplasia (coxofemoral joint laxity) in the immature dog improved, along with the recognition of pubic symphysis abnormalities in children born with hip dysplasia. JPS is a relatively simple procedure associated with little postoperative morbidity.

William B. Henry, Jr.

JPS surgery causes premature closure of the cranial pubic symphysis. The pubic symphysis is responsible for much of the longitudal growth of the pubis. "Premature" closure of the cranial pubic symphysis results in shortened acetabular branches of the pubic bones. This, combined with normal growth elsewhere in the pelvis, results in outward rotation of the acetabuli, thereby improving coverage of the femoral heads. This is similar to the effect gained by triple pelvic osteotomy (TPO), but it occurs gradually during the rapid growth phase.

Closure of the cranial pubic symphysis is accomplished either with an electrocautery needle applied through the physeal cartilage following a specific protocol for time and wattage, or by removal of the physeal cartilage with No. 12 and No. 15 scalpel blades, small bone rongeurs and curettes, followed by cauterization of the bone edges. With either technique, the insertion of the prepubic tendon must be removed to allow placement of a protective instrument to avoid urethral damage.

Following surgery, the puppies are walked on a leash, avoiding running and jumping for four to eight weeks. They are reevaluated two and four months after surgery by Ortolani palpation and standard ventrodorsal radiographs of the pelvis to assess acetabular coverage. Because hip dysplasia is a known heritable condition, neutering the pet is strongly advised.

JPS is a minimally invasive, relatively inexpensive procedure associated with minimal morbidity and may minimize coxofemoral laxity and therefore the progression of OA.

JPS surgery is more successful at an early age when a significant potential for growth remains, especially in puppies with high distraction indices. A successful outcome is one in which good femoral head coverage is achieved and hip joint laxity resolves, precluding the necessity for more invasive surgical intervention in the future (such as TPO, femoral head ostectomy or total hip arthroplasty) (Photos 1-3).

Photo 1: PennHip distraction view of a Labrador puppy at 14 weeks. The DI is 0.55.

Hip dysplasia is a very prevalent, complex disease and, as such, veterinarians should strive to become competent in early detection of hip laxity and knowledgeable regarding the principles of the surgical options available and the objective and subjective results associated with each.

Photo 2: The same dog at 28 weeks (14 weeks post-JPS).

This will enable them to better counsel their clients regarding breeding strategies, exercise programs and dietary management, as well as potentially beneficial surgical options for affected puppies.

Photo 3: The same dog at 50 weeks (36 weeks post-JPS).

Dr. William B. Henry, Jr. is an ACVS board-certified veterinary surgeon and past president of the American College of Veterinary Surgeons (ACVS). He currently practices with Cape Cod Veterinary Specialists and Boston Veterinary Specialists. His primary interest is orthopedic surgery. He is an avid fan of windsurfing, sailing and bicycling.