Hip Dysplasia Revisited
Dan Brehm, VMD, DACVS

Despite years of selective breeding based on radiographic hip assessment, hip
dysplasia continues to be a major clinical problem in dogs. Clinical signs
are most typically seen in larger breed puppies, usually starting between the
ages of five and ten months. Alternatively, clinical signs might not be seen
until the patient is older in association with chronic degenerative joint
disease. Common clinical signs include difficulty rising after rest,
difficulty climbing stairs, exercise intolerance, and an intermittent or
continual lameness. Puppies commonly demonstrate a "bunny hop" gait, in
which the hind legs move together during running. Physical examination
findings typically include pain on extension and abduction of the hips, hind
limb muscle atrophy (more typical in the dogs with chronic hip DJD), and
possibly palpable joint laxity (less typical in the dog with chronic DJD).     

Two major categories of treatment exist for hip dysplasia: surgical
management and conservative (medical) management. The basic components of
medical management are analgesics, exercise modification, and, if needed,
weight loss. In most cases, non-steroidal drugs are used as the analgesics
of choice. There are a large number of available NSAIDs to choose from, with
new drugs still emerging on the market. Chondroprotective agents, such as
Glycoflex and Cosequin, can be used as adjuncts. To date, there are no
controlled studies that demonstrate the true efficacy of these nutritional
supplements. Anecdotally, though, some dogs do respond. Some activitiy is
still beneficial to dogs with hip dysplasia to help maintain muscle mass, but
it is better to restrict activity to non-concussive activities, such as leash
walks and swimming. Finally, if the dog is overweight, weight reduction by
itself can significantly improve clinical function.    

There are three commonly utilized surgeries for the treatment of hip
dysplasia. Which surgery is chosen depends mostly on the integrity of the
femoral head and acetabulum at the time of diagnosis. The surgical treatment
options are categorized as prophylactic surgeries and salvage surgeries.
Triple pelvic osteotomy (TPO) is a surgery performed in dogs with hip
dysplasia in whom there is no to minimal degenerative joint disease
associated with the hip dysplasia. The ideal candidate is a younger puppy
(six to eight months of age) with mild to moderate coxofemoral subluxation
and no DJD. Younger dogs still have growth potential and can better remodel
their hip joints following TPO surgery. The goal of this surgery is to
reorient the femoral head-acetabular relationship to in effect tighten up the
hip joint. This will result in better and more uniform distribution of
weight bearing forces through the joint and lessen the degree of developing
DJD. A recent study did show that most dogs will still develop some DJD
after surgery, but that clinical success is greater than 85%. This study
also showed that mild DJD is not necessarily a contraindication to this
surgery. This is the surgery that we prefer to perform if the hip integrity
is not too severely compromised and (most importantly) the puppy is
clinically affected by its hip dysplasia. Femoral head and neck excision
(FHNE) had been the surgical treatment of choice for hip dysplasia/arthritis
for many years, but has gone somewhat out of favor since the more recent wide
availability of other surgical options (see total hip replacement below). It
remains the the treatment of choice in cats and small dogs with clinical hip
DJD, and can be used successfully in medium and large breed dogs. Total hip
replacement is the ideal surgery because it both eliminates the pain
associated wit hip DJD and returns the hip joint to normal mechanical
function. Total hip replacement (THR) is associated with a greater than 90%
success rate. Dogs must be skeletally mature before a THR surgery can be
performed (minimum age before surgery is 12-13 months). In most cases, dogs
will return to normal function after a THR surgery is performed. Also, in
most cases, the hip protheses will last the life of the dog.    

All three surgeries are performed by the surgery service at SouthPaws. The
treatment chosen depends on a number of factors. We prefer TPOs if the dog
is young and has minimal degenerative changes. Total hip replacement is the
surgery of choice in large or giant breed dogs who have advanced arthritis.
Femoral head and neck excision is the treatment of choice in small dogs and
cats and in some larger dogs. As always, the surgery is selected after a
thorough discussion with the clients and consultation with the referring
veterinarian. If there is any additional information that can benefit you,
as the referring veterinarian, please feel free to call Dr. Siemering or Dr.
Brehm at 703-451-0909.

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