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CANINE RESEARCH PROGRAM
The small animal component of the J.D.
Wheat Veterinary Laboratory draws from many established leaders in the
field of canine orthopedics, whose work has raised the standard of care
in the management of musculoskeletal injury and diseasese. This body of
work has addressed surgical management of hip dysplasia with total joint
prosthetics, repair of ruptured CCLs (cranial cruciate ligament),
and extensive investigations into categorizing, understanding and clinically
managing chronic and acute lameness. This work continues among faculty
and residents of the school; however, the current focus of this small animal
program is establishing an extensive project investigating elbow dysplasia.
Canine Elbow Dysplasia Research Program
Background
The J.D. Wheat Veterinary Orthopedic
Research Laboratory at the University of California has established a comprehensive
research program into canine elbow dysplasia under the direction of Dr.
Kurt Schulz. Elbow dysplasia is the most common forelimb orthopedic disorder
in large breed dogs. A complex group of diseases comprises this disorder,
including:
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Fragmentation of the medial coronoid
process (FCP)
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Ununited anconeal process (UAP)
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Osteochondrosis dessicans (OCD)
-
Elbow arthritis of unknown origin
All of this conditions in this group
lead to chronic and often crippling pain, particularly among active large
breed dogs. Despite the severity and high prevalance of elbow dysplasia,
little research is currently underway to determine its causes or effective
treatments. This may be due in part to the condition's complexity
and the advanced research techniques necessary for these studies. The VORL
is uniquely poised to address this problem with expert faculty and superior
facilities.
Fragmentation
of the medial coronoid process (FCP)
Fragmentation of the medial coronoid
process or FCP is probably the most common of these diseases. FCP
affects many large breed dogs particularly Labrador Retrievers, Golden
Retrievers, Newfoundlands, and Bernese Mountain Dogs. In this disease a
small portion of the joint surface (coronoid process) of one of the three
bones that make up the elbow joint (the ulna) breaks of within the joint.
This loose fragment is thought to contribute to the pain and arthritis
associated with this problem. In addition, however, there are other
relatively large areas of the joint that loose cartilage and contribute
to the pain of this disease. The underlying cause of this disease
remains unknown. The most popular theory is that abnormalities in
the growth of the bones that make up the elbow joint lead to poor fit of
the joint and subsequent formation of bone chips. Surgical treatment
of this disease has been limited to surgical or arthroscopic removal of
the bone fragment and attempts to realign poor fitting joints. Generally,
surgical management has not been shown to be better than medical treatment
with aspirin or other analgesics although the value of arthroscopic treatment
has not been well evaluated. Attempts to control FCP have been led
by the UC Davis Wind-Morgan program that applies radiographic screening
for early detection of the disease prior to breeding. Unfortunately
the minimal understanding of the underlying causes of this disease have
significantly limited the success of both treatment and prevention of FCP.
Ununited anconeal
process (UAP)
Ununited anconeal process or UAP is
a disease primarily of German Shepherds. In this disease a much larger
portion of the ulna fails to fuse with the remainder of the bone.
This large portion of the ulna is important to joint stability but in UAP
it remains loose in the joint, contributing to arthritis and joint instability.
Again the specific cause of this problem is unknown but is likely related
to abnormalities in bone growth. Treatment in this case may involve
removal of the loose bone, surgical reimplantation, or attempted joint
realignment. Like FCP, the success of surgical treatment of UAP has
been very limited as have attempts to eliminate the disease by controlled
breeding programs.
Osteochondrosis
dessicans (OCD)
Osteochondrosis dessicans or OCD is
a disease that occurs in both humans and dogs and may occur in any of several
joints. When OCD occurs in the shoulder joint it may be treated very
successfully probably because of the large size and simple shape of the
joint. When OCD occurs in smaller joints such as the elbow or hock
the outcome is much worse, leading to arthritis and chronic lameness and
pain. OCD is due to an abnormality of bone maturation resulting in
a joint surface that cannot tolerate normal activity. This leads
to tearing of cartilage and subsequent pain. Treatment of this disease
involves surgical or arthroscopic removal of damaged cartilage and analgesic
therapy. Again, the success of prevention and treatment of this disease
in the elbow of dogs has been very limited.
Elbow arthritis
The end result of any disease of a
joint is arthritis. While intensive research is underway investigating
the causes and treatment of arthritis in humans and animals, a cure is
still probably many years away. Arthritis in the elbows of dogs can
be particularly crippling because dogs carry more of their weight on their
front limbs than they do on their hind limbs. Arthritis of the elbows
usually causes intermittent or chronic lameness, exercise intolerance,
and chronic pain. The most common treatment of arthritis in any species
is the use of analgesics; however, numerous surgical therapies including
total joint replacement may aid in the alleviation of pain associated with
this disease.
Current Goals
of the Elbow Dysplasia Research Program
-
Elucidate the underlying causes of
elbow dysplasia
-
Develop effective treatment modalities
-
Develop screening techniques to aid
in the elimination of these diseases
Causes of Elbow
Dysplasia
The underlying theory in the cause
of elbow dysplasia is an abnormality in bone growth leading to poor joint
conformation. Abnormalities in joint conformation subsequently lead
to the fragmentation and destruction of bone and cartilage. Early
studies in our laboratory have successfully determined the patterns of
normal joint conformity through a technique called joint casting.
These important studies have enabled us to determine the precise locations
where weight is transferred in normal joints. This work now allows
us to study conformity in diseased joints to determine if this plays a
role in elbow dysplasia.
A similar study using a technique
called pressure sensitive film analysis allows us to determine the specific
amount of force transferred through different regions of the joint.
This technique permits us to further determine the role of joint conformity
in elbow dysplasia and enables us to evaluate the effects of different
surgical procedures designed to improve joint conformity.
Developing Treatments
for Elbow Dysplasia
Our investigations into the treatment
of canine elbow dysplasia include the use of arthroscopy, antiarthitic
medications, and physical therapy. The Veterinary Medical Teaching
Hospital at UC Davis is a leader in the use of arthroscopy in canine surgery,
treating several cases every week with advanced instrumentation and techniques.
In conjunction with orthopedic surgeons at the UC Davis Medical Center,
we are able to apply the most advanced surgical techniques available for
the arthroscopic management of joint disease. Evaluation of the success
of these techniques is performed by computerized gait analysis of our patients
using a force plate analyzer. This system allows us to determine
the exact amount of force our patients are applying through each limb,
enabling us to monitor for improvement in lameness following various treatments.
Force plate analysis in conjunction
with ultrasound muscle mass measurements also allow us to determine the
effects of physical therapy protocols on our patients improvement. These
techniques are also being employed to evaluate the efficacy of antiarthitic
medications and analgesics on canine elbow dysplasia.
Screening
Our major ongoing study aimed at prevention
of elbow dysplasia uses quantitative computed tomography (QCT) for detailed
analysis of the bones of the elbow. QCT enables the determination
of the density of bone around the joint. This density in turn reflects
the interactions and loads within the bones of the joints and possibly
can detect abnormalities earlier than any other technique. QCT makes
use of advanced Cat Scan equipment and software developed in our laboratory.
The results of our studies using QCT analysis may permit early detection
of abnormalities that lead to elbow dysplasia thereby improving preventive
breeding programs and aiding studies in the genetics of elbow dysplasia.
In addition, this early disease detection may enable rapid surgical management
that may lessen the severity of the disease as our patients age.
If you are interested in supporting
programs and research activities related to the canine research program,
please contact Dr. Kurt Schulz at ksschulz@ucdavis.edu.
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