Case of the day: Puppy has a sore leg.

I just saw a beautiful little 4 month old lab puppy who was limping.  I thought it would be fun to walk you through how we approach a case like this in a real life situation.  

For those of you who are reading this now, I originally posted this with no diagnosis.  But now, the diagnosis is written at the end of the story.

Signalment:

This is a 4 month old Labrador Retriever.  She is not spayed.

History:

She was playing roughly with her “older sister” who is a much larger lab when suddenly the owner heard her scream very loudly.  This happened early on Saturday morning.  (It is now Monday morning.)  Since then, she has been bright and happy and eating well, but she is barely putting any weight on her left hind leg.  It hasn’t gotten any better or worse since it happened.

Physical Exam:

The dog was crazy excited and just wanted to lick me instead of being examined.  :)  The first thing I noticed is that she was not putting any weight at all on her left hind leg.  Her heart rate was 130bpm.  Her temperature was 38.6 C (101.5 F).  Here is what I noticed when I palpated her leg:

• I didn’t see anything unusual on her toes, toenails, or skin anywhere on the leg.
• She let me flex and extend her toes and her stifle (knee) without concern.
• At first I thought she was sore when I extended her hock.  But, when I repeated this, she didn’t seem sore.
• None of the joints were obviously swollen.
• There was no drawer sign in her stifle.  (This is a test that we do to determine if there is a tear in the cruciate ligament.)
• She was reluctant to extend her hip.  She could do it, but she pulled back against me when I tried, and she cried if I tried to do it repeatedly.  She could abduct her hip.  (“Abducting” is the movement a dog would make when they lift their leg to pee.)

When I finished the exam she was even more sore on the leg.  (Yeah, I know, I’m kind of mean, but hey…you have to do stuff like this when you are a vet.)

Tests:

We decided that we needed to take some hip xrays.  She shouldn’t be this sore.  She was a little difficult to keep still on the xray table, so we ended up using a cool padded trough that we have which helps dogs to be more comfortable when they lie on their back.  Here’s the xray we got (click to enlarge):

On the xray above, she is on her back, so the bones on the left of the picture are actually her right side.

Diagnosis and Treatment:

So perhaps I have been a little tricky in giving this case as a “Guess the Diagnosis” case.  I say this because the xrays really don’t tell me anything at all!  The hips look fine.  A few of you mentioned the possibility of hip dysplasia.  Dogs with hip dysplasia will have a number of changes that we can see on xrays.  You will see that much of the “ball” portion of the ball and socket joint is not sitting in the “socket”.  In medical terms, the head of the femur is not well seated in the acetabulum.  You will also see that the neck of the femur is wider than it should be.  And, the head of the femur tends to get flatter than normal when a dog has hip dysplasia.  I’ve created a graphic to show the difference.  The hip on the left is the one from our patient.  The hip on the right is a dysplastic hip (click to enlarge):

So, the final verdict was that there was likely nothing serious going on.  I suspect that she had a deep muscle bruise.  I put her on a pain reliever called Previcox.  (This is an NSAID drug very similar to Metacam, Rimadyl or Deramaxx).  She was also instructed to rest, which is a very difficult thing to ask of a lab.

How is she now?

Today (24 hours later) I gave the owner a call to see how our patient was doing.  It turns out that she is 90% better already!