Heel crack w/old injury to coronary band

[barnrat1]

13 yo Trakehner mare with old injury of many years to LH heel area involving coronary band with irregular hoof wall growth. Has has had ongoing quarter crack kept under control with good farrier management by previous owner (many year show record). She has been layed up for suspensory injury for the better part of a year (LF). Started legging up slowly and noted crack began to widen and ultimately extend into the sensitive tissues. Also noted she was cocking this foot at rest most all the time. Farrier floated crack in March and she had immediate relief as evidenced by normal stance pattern. She is in regular shoes.

Legging up continued with addition of trot work. Cracked/floated hoof segment now shows buckling as though it is under pressure. She once again exhibited cocking of the LH constantly at rest and was grade 3/5 lame on lameness exam. (Blocks, x-rays and nuclear scintigraphy all performed which were negative). Farrier says heel still floated. I can see very, very little space between shoe and hoof. My question is, how could it be floated and show buckling?

I might mention that my farrier kept her hind feet quite long (said she's a big horse and needs a lot of foot under her). But I feel this has contributed greatly to the exacerbation of her heel crack. How do you think we should proceed? Farrier inclined to resect heel but I'm not sure what that would accomplish as hoof wall will continue to grow out damaged due to old coronary band injury. Any advice or insight you could provide would be most appreciated. Thank you. (Can upload pix if it would be helpful.)

[calshoer]

Pictures will sure help but here is some general information on quarter cracks.
A long foot supports no more than a short foot. Heck draft horses have very short feet compared to the width.
A foot that is overall long also will have long heels, and a long heel will by its very angle of growth end up too far forward under the foot to properly support the horses weight coming down through the leg. .
And the excess weight bearing coming down BEHIND the end of the heels will bend the hairline and blow a quarter crack.
Look close. I bet the end of the heel (the foot not the shoe) is DIRECTLY under the top of the crack.
Trim the heels back down where they belong and that moves the base of support behind the crack.
Float the portion of hoof behind the crack. Use a bar shoe to engage the frog.
The hairline will level out, the crack is under less pressure and it should begin to heal in. BUT long term crcks do develop permanent damage to the unerlying tissues so it could become chronic and require careful maintainance.
And once the heels re rerimmed down where they belong, the breakover pount MUST also be addressed or the tendons and ligaments of the leg will be stressed. As well a long toe contributes to heel distortion. In other words, BOTH ends of the foot must be trimmed and shod correctly. Patty