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View Previous Case of the
Month Reports- click here
 Ashley
is a 100 pound, 4 year old Yellow Lab who presented to us with a sudden
onset of
lameness in the right shoulder. According to her owner, there
was no distinctive incident which brought on the lameness. There had
been no recent
travel
history,and there were no other pets in the yard with Ashley
and she had
no previous history of lameness in this or any other leg.
Ashley's
owner was unable to find the source of the pain in the leg, but thought
that
it might be in the foot.
On physical
exam, Ashley was in good spirits, bouncing around the exam room
as most
labs do. She had no other physical problems except that she was about
10 pounds
too heavy (another common problem among labs). She was obviously lame
on her
right front limb. When examining a pet for lameness, we typically place
a muzzle
on the pet
to prevent accidental bites when the sore point is manipulated. Once the
pet
is safely
restrained, we examine each joint of the foot for pain or swelling. We
check the
pads and
toes for foreign bodies (such as foxtails, glass, metal or wood). We
move up the
limb
feeling the bones and joints one by one until we find the painful area.
In Ashley's case, the pain was not obvious until we reached the shoulder
region. Once
we knew
which part of the body was affected, we sedated Ashley to take
radiographs (x-rays) of the affected area.
 
lateral view notice the joint mouse on the
left front to back view the mouse is in the center
of the picture
Click on the images to enlarge
In these
films you can see that there are small fragments of bone located in the
joint. These fragments are known as "joint mice". They arise from a
disease called "osteocondrosis dessicans (OCD), which affects large
breed dogs during their early growth years. In this disease, the
cartilage on the articular (gliding) surface of the joint, becomes loose
from the underlying bone. Similar to a skin blister. With time, the
"cartilage blister" may tear and the piece or pieces of cartilage will
be left floating in the joint. As you can imagine, if the cartilage
comes between the two weight bearing surfaces of the bones, it can be
quite painful, like having a pebble in your shoe.
(click on picture to
enlarge)
The
shoulder joint has a an outpouching in the front and rear of the joint.
In Ashley's case, the fragments moved into the rear pouch and probably
stayed there for some time. Over time, the cartilage fragments began to
absorb calcium and became small bone fragments. With the calcium inside
them, they became much harder and therefore more painful when they would
slide in between the articular surfaces of the humerus and scapula.
OCD can
occur in all the major joints, but happens most frequently in the
shoulder, elbow and knee.
We
discussed the radiographic findings with Ashley's owners and agreed to
perform a joint
exploratory to remove the fragments. Ashley was anesthetized and we
opened the joint after some arduous dissection. The stones were right
where we expected them to be, and we removed them. The joint surface
was a bit irregular where the cartilage had blistered off, but it was
relatively smooth. The joint was irrigated and closed with sutures.
Ashley
awoke soon after surgery and was up and bearing weight on the limb by
the next morning. We administered joint protective agents (adequan and
cosequin) and pain relief medication in the form of a non steroidal
anti-inflammatory (Deramaxx). We put her on a strict diet to help her
lose 10 pounds which should reduce the trauma to the joint. She was
discharged with orders to restrict activity severely for 2 weeks.
When we
last checked, she was recovering nicely at home.
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