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WHAT IS A TOTAL HIP
REPLACEMENT (THR)?
A THR is a prosthetic hip
that is implanted in a similar fashion as is done in people. It
replaces the painful arthritic joint. The modular prosthetic hip
replacement system used today has three components – the femoral stem,
the femoral head, and the acetabulum. Each component has multiple
available sizes which allow for a custom fit. The components are made
of cobalt chrome stainless steel and ultra high molecular weight
polyethylene. Prosthesis implantation may be cemented or cementless
(press-fit).
WHAT DOES CEMENTED AND
CEMENTLESS MEAN?
Both cemented and cementless systems are available. Each system has
advantages and disadvantages. Your dog will receive whichever is best
depending on several factors including your dog’s age as well as the
severity and duration of the arthritis present. Cemented components are
held in place by the bone cement plus on-growth of bone once the
prosthesis is in place. Cementless components are held in place by
precise initial implantation plus bone in-growth into the surface of the
implant. Cementless prosthesis implantation demands greater surgical
precision.
WHAT ARE THE COMPONENTS MADE
OF?
The
cemented components are made of cobalt chrome stainless steel and
ultra high molecular weight polyethylene.
PMMA, or polymethylmethacralate, is bone cement used to hold the
implants. A portion of the surface of the cementless implants is covered
with 250 micron diameter titanium beads.
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| Cementless Prosthesis |
Cemented Prosthesis |
WHY CHOOSE A TOTAL HIP REPLACEMENT?
A THR is performed to improve
quality of life by providing pain relief, better hip function, and
return to an active life. The arthritic joint is replaced with the
implant so the pain of bone rubbing on bone in the arthritic joint is
gone. Stability of the hip is returned. The decreased range of motion
of the arthritic joint is also corrected to allow good range of motion.
IS YOUR COMPANION A CANDIDATE
FOR A TOTAL HIP REPLACEMENT?
HOW DO PATIENTS FEEL WITH A TOTAL HIP REPLACEMENT?
Most walk on their new hip
immediately after surgery. Most clients report the personality improves
and that they feel great. Gradual return to normal function is allowed
between 6 to 10 weeks after surgery. Long-term studies found THR to be
a very effective method of treating disabling conditions of the canine
hip. The majority of dogs displayed marked improvement in walking,
sitting, climbing stairs, standing, running, getting into the car,
playing, and exercise following surgery. THRs have been performed in
both pet and working dogs with equal success.
DOES A TOTAL
HIP REPLACEMENT 'WEAR OUT'?
The life span of a
THR in people is approximately 10 to 20 years. Replacement of
implants due to wear and tear has not been necessary in dogs
partly because dogs weigh less than people, their weight is
distributed on four rather than two legs, and their average life
span is considerably shorter.
SHOULD BOTH HIPS
RECEIVE A TOTAL HIP REPLACEMENT?
Only one hip can be done at a time. The
most painful hip should be replaced first. If pain is present on
both sides, both sides should be replaced. The interval between
surgeries is about 6 to 10 weeks.
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A
bilateral THR with cemented and cementless hips. |
WHAT DO DOGS AND
CATS GO
THROUGH TO GET A TOTAL HIP REPLACEMENT?
The surgery takes 60-90
minutes. They are under continuously monitored inhalation
general anesthesia. Vital parameters, such as heart rate, heart
rhythm, tissue perfusion, blood oxygen content, respiratory rate
and pattern, temperature and blood pressure are monitored. The
surgery is performed with extensive precautions to prevent
infection. Much attention is paid to preoperative preparation
of the patient, instrument preparation, aseptic technique, and
environment control in the operating room. The patient’s leg is
occasionally clipped and bathed a few days prior to surgery to
ensure healthy skin.Pain medication is
administered and maintained postoperatively as long as is needed. The
patient is hospitalized with 24-hour patient care. The patients
routinely support some weight on the leg immediately postoperatively.
They are generally released from the hospital on the second
postoperative day – sometimes the next day..
WHAT IS THE
AFTERCARE?
The dog should remain inactive for
6 weeks postoperatively. They should be indoors, but
walked outside on a leash to eliminate. Vigorous
and strenuous activity is to be avoided during this time
period.
A good traction surface is helpful to prevent an accidental
fall.
ARE THERE ANY RISKS?
Yes. The incidence of
complications is very low, but risks exist just as they do for
surgery in people. Complications such as infection, luxation,
neurapraxia, loosening, technical problems, and anesthesia
incidents can never be totally eliminated. Extreme precautions
to minimize complications and anesthesia problems are taken by a
surgery team with a combined experience in veterinary surgery of
over 40 years. Problems with this highly technical procedure
are minimized by the frequent repetition of the same team of
surgeons and scrub nurses using the most advanced
instrumentation available.
According to the implant
manufacturer, Gulf Coast Veterinary Surgery is the leader in numbers of
THRs being performed in the state of Texas and is among the leaders in
the country.
WHEN SHOULD THE
SURGERY BE PERFORMED?
Surgery is recommended when pain or
lameness is present. The hip will be painful when extended and/or
abducted. Radiographs of the hips are used to confirm the
diagnosis of osteoarthritis. A conservative approach using
pain relievers for arthritis may be initially recommended. Surgery
is recommended if medication is needed over an extended period of
time or if it is ineffective. Long delays in performing surgery can lead
to longer rehabilitation time. THR is ideally performed before
severe bony remodeling and atrophy of hind leg muscles occurs.
Additionally, a delay means less time for your dog to enjoy the
improved pain free function provided by the hip replacement.
HOW DO WE GET
STARTED?
Schedule an appointment for a consultation
and examination of your dog. If available, bring radiographs and
copies of recent lab work performed by your veterinarian. A
referral to Gulf Coast Veterinary Specialists from your
veterinarian for an appointment is recommended. If your dog is a candidate, the surgery
will be scheduled. We
ask that you bathe the skin the day before
surgery. Radiographs of the hips will be taken if necessary on
the consultation/examination day.
For more information on Hip
Replacement Implants: BioMedtrix.com
The Specialists at Gulf Coast Veterinary Surgery, Orthopedics
& Neurology are available to
consult with your veterinarian.
Please call if you have any questions:
Phone: 713-693-1122
Fax: 713- 693-1110
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arthritis
due to hip dysplasia or other causes. Most are over 8 months of
age (our oldest patient was 16 years old), and weigh more than 6
pounds. 
