Re: Chronic laminitis Shetland pony

Lavinia Fiscaletti

Hi Anna,

I've redone the mark-ups in Wixie's album:

The angle that the radiographs were shot from isn't a true lateral as you can see the bottom of the foot. This means the beam was angling upward to some degree as opposed to being centered on the middle of the hoof capsule. This distorts the view, making it harder to accurately judge the sole depth and alignment.

Sinking is when the coffin bone is sitting deeper inside the hoof capsule than it should be. Yellow line #1 runs thru where the coronary band is located. Yellow line #2 points to the extensor process of the coffin bone. These two structures should line up with each other. They do not so the distance between the lines denotes the amount of sinking.

There are two different types of rotation: Capsular and bony column. Bony column refers to how the bones themselves line up from top to bottom. In bony column rotation, the coffin bone tilts down from where it should line up with the rest of the bones. The pink line on the radiograph follows the alignment of the bony column - all the bones line up as they should so there is no bony column rotation. 

Capsular rotation refers to how the dorsal wall of the hoof capsule aligns with the dorsal surface of the coffin bone. In capsular rotation, the distance between the two gets larger as you go from top to bottom. This is what is happening with Wixie's feet. This is a trim issue that can be fixed by getting the breakover set where the bony column needs it to be so the tearing forces on the already damaged laminar connections are removed. While the already damaged material can't heal and become better attached, the new better attached growth can grow down to ground level and replace this damaged material IF the trim is very strictly and correctly  maintained.The green line on the radiographs follows the angle of the new growth coming in under the coronary band toward the ground. Note how the green line runs parallel to the pink line but the dorsal wall of the hoof capsule does not. As long as the toes remain too long and the breakover stays too far ahead of where the bony column needs it to be, you won't be able to get rid of the laminar wedge material (scar tissue). Where the pink line ends, beyond the tip of the coffin bone, is where the breakover needs to be set. There should be NO hoof capsule at ground level beyond this point.

Agree with your farrier that if the trim is corrected, Wixie should be able to grow out the damaged material in 6-9 months provided the underlying cause has been removed.

Lavinia, George Too, Calvin (PPID) and Dinky (PPID/IR)
Nappi, George and Dante Over the Bridge
Jan 05, RI
Moderator ECIR

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