Laurie's Blogs.

That headline only makes sense to people who lived through the 80s & 90s and can sing along with most Tina Turner songs of that era!

Laurie – I have a patient with bilateral hyperextending tarsal joints. I thought I could order
 Therapaw tarsal supports to limit his hyperextension. Under what circumstances do you use a splint? I understand building up the support system on the opposite side of the joint, but what's to keep the joint from rolling forward thru the over-stretched joint capsule and cranial side ligaments?

It is a matter of realizing that the gastrocs must work eccentrically most of the time when the animal is weight bearing - preventing flexion collapse of the tarsus in stance, & shock absorbing on initial contact with any sort of gait pattern.  It will work concentrically to push the body forwards at end stance phase and/or extend the tarsus.  Going by known muscle principles - concentric is easier than eccentric.  Eccentric requires more strength.  Stand on a stool or stair step with your heels hanging over.  Now  go up onto your tippy toes - you use gastrocs to perform this movement - concentrically.  Now slowly lower yourself down, down, down, down - stop along the way if you wish....this is all eccentric.  Which was harder?  Which required more control?  (The right answer is going slowly down).

So.... if your dog has weak gastrocs - the options (or ramifications) for the dog are to collapse into flexion / stretch out the calcaneal tendon mechanism, and develop 'falling hocks'.  OR to utilize gastrocs in an 'easier' way - concentrically - and push up and over in order to utilize ligamentous support to maintain an upright position.  When doing the latter, the dog only has to use gastrocs concentrically 'here and there' to get into a state of minimal use.  A seemingly 'great, energy-sparing plan' for the weak-gastrocs dog!  But, the ligaments can become damaged & stretched over time.  So the therapeutic plan of action MUST BE to strengthen the gastrocs.

Why not a brace in this scenario? 

A brace will definitely help to protect the anterior ligaments at the tarsus - but does little to retrain proper strength and motion in this scenario.  In junior high and high school, I played on all of the competitive sports teams, and I had to wear ankle braces because I had such weak ankle ligaments from previous sprains.  What I noticed was that when I was not on the court or field - just walking down the sidewalk - that if I walked on so much as a pebble, it threw me off balance and I could go down!  Literally re-twist my ankle and fall over... just because of a stupid pebble on the sidewalk!  Not until I got into PT school did I start to understand that what I NEEDED to do was to retrain to strength in my calves and improve my proprioception and reaction times of these muscles in order to 'save myself' from pebbles on the sidewalk.  The braces had weakened these systems in me, made me rely on the braces even more, and in turn, made me vulnerable to minor displacement forces!!  I see this too as being a potential problem with the dog with hyperextending hocks (or slipped hocks - to use the lay-term).

Beyond the scenario described above, one would have to consider the potential ramifications or negative side effects of utilizing a brace or splint - soft tissue wear and damage, altered gait patterns, compensatory lesions elsewhere in the body.  So I think there are plenty of things to weigh into your decision making of utilizing  a splint/brace tarsal hyperextension.

When do tarsal braces make sense (in my opinion)?

1)  The dog with falling hocks / dropped hocks / a stretched out Achilles/Calcaneal tendon complex

2)  The dog with a partial tear of the gastrocs or SDF tendons (but if there is a full tear of either of these... I think a surgical intervention is most appropriate)

3)  A full or partial tear of the 'accessory tendon' of the calcaneal tendon

4)  The dog with a full or partial tear of the gastrocs where surgery is not an option (for whatever reason)

5)  Post-op repair of any portion of the calcaneal tendon 

6)  A traumatic injury involving damage to the ligamentous support of the tarsus

7)  An autoimmune reason for weakened ligaments/tendons

Perhaps there are more reasons... but I am stopping here - as we could start to get into weird, uncommon pathologies... which is not the point of this discussion.

Now, my caveat would be... that granted if the brace was constructed so as to allow full flexion but simply stop hyperextension (such as with a custom made brace)... then such a brace would not have the same deleterious consequences as a rigid splint...but you would still have to think about the compensations / negative side effects (listed above), as well as the cost factor... IF, IF, IF you have a dog that would quite simply just be a good candidate for strengthening techniques.

Long winded as usual - until next time,

Laurie