DDFT Tenotomy, Dr O'Grady?

[Peter Lundin]

I would like some opinions on the indications and the outcome of tenotomy.
Peter Lundin DVM

[Tom Stovall, CJF]

Peter Lundin DVM in gray

I would like some opinions on the indications and the outcome of tenotomy.

Most of the equine practitioners with whom I labor are of the opinion that a tenotomy is indicated when the dorsal surface of the third phalanx approaches vertical.

Assuming proper aftercare, which must include support of the bony column, enhanced turnover, and remodeling of the hoof capsule, the prognosis for a return to previous levels of use/performance is good for bloodstock, fair to poor for rail horses, and extremely poor for speed horses.

[Stephen E. O'Grady, DVM]

Indications for a deep digital flexor tendon tenotomy in laminitis are:

Progressive severe rotation

Persistent pain with no sole growth

coupled with minimal hoof wall growth at toe

Secondary flexor apparatus contracture

Outcome is excellent when accompanied with appropriate farriery to realign the third phalanx

Tenotomy is contraindicated in laminitic cases that show marked distal displacement of P3 (sinking)

Stephen E O'Grady, DVM

[Ronald Aalders]

Tenotomy is contraindicated in laminitic cases that show marked distal displacement of P3 (sinking)Stephen E O'Grady, DVM


Hi Dr. O'Grady,

I just wondered why a tenotomy would be contraindicated in sinker cases. I can see why it won't do the horse much good, but why would it be contraindicated?

Also you refer to realigning P3 before performing a tenotomy. Would this be of equal importance when perfoming a desmotomy, like cutting a check ligament in a club case?


Ronald Aalders

[Stephen E. O'Grady, DVM]

I just wondered why a tenotomy would be contraindicated in sinker cases. I can see why it won't do the horse much good, but why would it be contraindicated?

Why do surgery when it will be of no value?

Also you refer to realigning P3 before performing a tenotomy. Would this be of equal importance when perfoming a desmotomy, like cutting a check ligament in a club case?

Absolutely

Good questions as always Ron

Stephen E O'Grady, DVM

[Stephen E. O'Grady, DVM]

Ron

I have attached an example. Note the straight alignment of P1,P2,P3. The DDFT is playing a very small role here. When you transect the tendon, there is basically no gap. I've been here too many times - I no longer operate these cases.

Stephen E O'Grady, DVM

[Stephen E. O'Grady, DVM]

Sorry Ron - here is the example

[Phil Armitage]

Out of curiosity what caused this one?

[Stephen E. O'Grady, DVM]

Out of curiosity what caused this one?

Corticosteroids

[Phil Armitage]

Seen that before, poor horse is at risk of dying either way.

[Tom Stovall, CJF]

Denise McLain in gray

I've asked this question before and am still curious as to why one can have a sinker like this and have no rotation of the coffin bone if there exists a "pull" from the DDFT? If the tendon has been transected in cases like this and it doesn't separate a couple of inches like you normally see, what has happened to all that tension? Maybe the "pull" theory needs some rethinking or refinement? Any ideas?

Perhaps "sinker" is a misnomer. With near total laminar dysfunction, the partially detached hoof capsule is displaced upward on loading (hence the lipping). This upward movement reduces the pull of the DDFT and suggests a tenotomy would be ineffective with sinkers.

[Stephen E. O'Grady, DVM]

I've asked this question before and am still curious as to why one can have a sinker like this and have no rotation of the coffin bone if there exists a "pull" from the DDFT? If the tendon has been transected in cases like this and it doesn't separate a couple of inches like you normally see, what has happened to all that tension? Maybe the "pull" theory needs some rethinking or refinement? Any ideas?
Denise

Briefly - There is an opposing pull of the DDFT against the dorsal lamina. The horse has a well developed dual blood supply in the heel of the foot when compared with the blood supply in the dorsal lamina which is coming from two directions with one flowing against gravity. With rotation, coupled with the weight of the horse, the DDFT distracts the third phalanx away from the dorsal hoof wall. The soft tissue in the back of the foot remains attached causing the bone to rotate.

With distal displacement (sinking) as Tom explained, the entire lamina is compromised allowing P3 to sink distad while the hoof capsule is displaced upwards. This accounts for the status quo in the DDFT. Look at Fig. 2 radiograph and you will see what is referred to as a "sinker line" which is the dorsal margin of the hoof capsule. It is located at the proximal end of P2. This will help you understand the mechanics.

Hope this helps

Stephen E O'Grady, DVM, MRCVS