Labrador front leg lameness

[lehughes]

Hi Laurie

Recently saw this dog-was referred by Surgeon-14 mo MN Labrador, 100lbs, very straight legged

chronic RF lameness

The Surgeon thought she could elicit pain on caudal humeral head-was thinking OCD lesion
X-rays neg for OCD of shoulder, elbows were clean-no evidence of dysplasia
CT was done of shoulder and elbow-no abn findings, Surgeon thought possible tendonitis but no sig findings on exam

Very active dog, stands with external rotation of shoulder, holds limb abducted, dec carpal extension, flexor tendons tight
Trigger points in Triceps, Pectorals and Teres Minor

When palpating-functional IR of shoulder with tightness at endrange
excessive ER of shoulder with hypermobility

When limb is abducted and IR there is a clunking and popping of shoulder joint with hypermobility-see video (is this a valid way to assess shoulder range?), we couldn't find much else other than TP's

I did not measure abduction angle, I am not very accurate at this-however he is coming in next week so I will try to get measurements

Do you think this dog could have MSI? at 14 mo and 100lbs,
Wondering your thoughts on the video-we compared L and right shoulder

any suggestions?

Thank you
AMM

Right front: https://youtu.be/wFEo238oE1A

Left front (for comparison): https://youtu.be/8FSotbmQhKk

[lehughes]

Hi AMM!

Very interesting indeed!
I have many thoughts running through my head!

1) Glenoid labrum tear… I’ve seen just a few (they responded great with shockwave - get to the medial side of the joint, laser, acupuncture, & nutraceuticals (but especially shockwave).
2) Medial shoulder instability (Does there feel to be hypermobility? They key to this test is to have the shoulder extended out forwards i.e. 1/2 way between the normal ‘straight down lie of the arm' and the face, then abduct (holding onto the leg from the elbow in order to keep it straight) and stabilize the scapula by putting pressure on it / on the acromion.
3) Could it be the biceps tendon flipping out of the bicipital groove?
4) I do think it’s likely shoulder, but always test C5 - T4, and ribs 1 - 4 as well.
5) Far out there, unlikely is a nerve sheath tumour… but just based on front leg lameness of undetectable origin - look for significant atrophy of a muscle / muscle group. I just feel like I would be irresponsible not to throw that out there, despite it not being likely in this case.

I think you’ve made up your own testing method… but that’s okay, because your finding stuff, and quite frankly, this is how tests are created. So you’ve found a positive, now to figure out positive for what! So I tested my Borzoi (who has MSI of both shoulders) and she doesn’t clunk. So again, I’m back to thinking labrum tear.

All in all, if you want to confirm or have a more definitive diagnosis, then I’d suggest a shoulder ultrasound. If the owners are not keen on further diagnostics, then try a trial of treatment for a presumed diagnosis of glenoid labrum tear.

Thanks for the videos. I’d love to see if anyone else has thoughts, opinions, or first hand experiences with something that shows like this!

Best of luck!

Laurie

[David Lane]

A CT is not a great imaging test for the shoulder. U/S (or high field MRI) is better. I have seen MSI cases go missed with low field MRI on smaller dogs, and common ultrasound probes can't properly image the medial compartment. If you truly want to rule out MSI, then dropping some sort of scope in there is the gold standard test. It will also rule in/out labrum tears, although these are less common. FWIW lateral glenohumeral tears have also been described.

I guess what I am trying to say is that a CT is not a valid test for ruling out MSI, biceps or supra issues so all of those Dx remain on the rule out list... MSI more so if instability is detected. I will also maintain that instability cannot be ruled out on large, strong, a/o nervous dogs that are not sedated (in the same way that a certain % of cruciate insufficient dogs will also escape detection until they are sedated), so a normal abduction angle on an awake dog is not 100% accurate either.

As to the clunking... I share your confusion with that. I've encountered many dogs that cavitate/clunk on exam, even while heavily sedated, and found no correlation between that and subsequent imaging results to suggest MSI. I've talked to colleagues about this issue, and everyone is scratching their heads as well. I'm sure it indicates something, I just don't know what.

David Lane DVM
ACVSMR