Answers to Some Questions about Laminitis and Founder

© Burney Chapman

posted here with the permission of the author

LAMINITIS is the inflammation of the laminae. Laminitis is generally agreed to be due to ischemia of the laminae causing detachment of third phalanx (PIII) from the horny wall.

FOUNDER is a maritime term meaning "sinking". Founder is secondary to laminitis and is the sinking of third phalanx (PIII) in the hoof.

CHRONIC FOUNDER is an old founder that has survived by some means. The third phalanx is demineralized, with lytic areas radiographically, is badly deformed, with periodic and/or chronic lameness. Intermittent inflammation can occur in chronic founder.

ACUTE CASES occur in a short course. Active abscesses may be prevalent with inflammation to the laminae bed. These conditions must be corrected before a favorable response can be expected.

SINKER is when the bony column sinks downward, inside the hoof capsule, and 100% of the laminae die. This condition should be considered an emergency and heart bar shoes applied and a hoof resection performed. If the blood supply is destroyed, all aspects of it returning are futile, however, the horse and feet can be salvaged if a live nail bed and a live coronary plexus remain intact.

1. What should I do if I suspect laminitis?
   • If the horse is shod, pull the shoes. A temporary first-aid measure can be provided by using a roll of gauze or carpet in the same triangular shape as the frog. This is placed directly on the frog for constant support and taped in position by using an adhesive bandage.
2. When should I call my Veterinarian?
   • If you suspect laminitis call the veterinarian. He will administer whatever medications he deems necessary for the underlying causes. Lateral X-rays are recommended at this time.
3. How soon do you recommend putting on heart bar shoes after the initial insult of laminitis?
   • Heart bar shoes should be applied as soon as possible to stabilize the bony column. The stabilizing effect of support of pressure on the frog seem to prevent laminae fatigue. In severe cases, where the laminae have become necrotic, the heart bar shoe should not be removed, but a hoof resection should be done. This is done to prevent pain from swollen laminae.
4. What are the reasons for doing a hoof resection?
   • To relieve the pressure on the coronary plexus by the coronary crown of the hoof wall.
   • To debride any necrotic laminae entrapped between third phalanx (PIII) and the wall. This can be treated as an open wound. Systemic antibiotics are of very little value as there is no blood supply to carry medication to this area.
   • When pressure is applied to third phalanx via the apex of frog the anterior edge of third phalanx will have no resistance to it thus forcing the third phalanx back in a more normal position.
   • To relieve any edematous swelling which occurs between PIII and wall.
5. Why does the Veterinarian need to run an SMA 12 or SMA 20?
   • This is done to determine any underlying causes that affect the feet. Treatment begins with an accurate diagnosis and evaluation of the primary cause.
6. How much pressure (support) must be applied to the frog?
   • The amount of support varies with each individual case. This depends upon the amount of rotation of the PIII at the time of application and whether the sole is dropped. Stabilization of the third phalanx is calculated by measuring the amount of rotation. It is critical that the apex of the heart bar contact the frog in front of the insertion of the deep flexor tendon on the third phalanx, however, it must end at least 1 cm. palmar to the apex of the frog. The bar must not touch the sole at any point and must be sufficiently narrow to avoid applying pressure to the medial and lateral palmar digital arteries as they enter the foramen of the terminal arch deep to the digital cushion.
7. How far forward should the bar of the heart bar shoe be placed on the frog?
   • Again, let me stress that the bar should not touch the sole in any manner. It is usually made of 1/4" X 1/2" bar stock and is "V" shaped, just like the frog. This bar, on the normal light horse of today, should extend along the frog to a point of 3/8" (6-7 mm) posterior to the apex. Problems arise if the bar is too long.
8. Does the heart bar cause necrosis of the sensitive frog or digital cushion?
   • If the shoe is correctly applied the heart bar will not cause necrosis. Abscesses usually occur within 15 to 30 days from the first signs of laminitis, if there is edematous swelling of the laminae, sinking and/or rotation of PIII. Abscesses will normally be aseptic in these early stages. It is beneficial to use ichthammol thickly applied to the coronary band, daily or as needed, for the first 30 to 90 days of treatment. This is done to keep the coronary band soft and pliable.
9. When do I expect abscesses to occur?
   • When more than 4 degrees of edematous swelling occurs of if sinking and/or rotation has occurred, abscesses will develop. Abscesses generally result within 15 to 30 days after the heart bar shoes have been applied. If this takes place the soles should be opened at the junction of distal laminae and the horny sole. Opening the sole at this junction helps prevent swollen solar corium and resulting exuberant tissue.
10. How should I treat decubitus ulcers or bedsores?
    • On non-suppurating decubitus ulcers, zinc-oxide and maalox mixture (approximately one bottle of maalox to one tube of zinc-oxide) is helpful. On suppurating decubitus ulcers betadine ointment is used. These horses should be bedded on straw or shredded newspaper.
11. How should I deal with osteomyelitis?
    • It normally will occur when there is an exposed bone and must be addressed by only those who are extremely knowledgeable in treating this problem. The severe cases result in chronic abscesses. These can be treated with sugardine but most often require surgery which involves a bone biopsy, a culture and sensitivity to determine what antibiotics are beneficial for treatment. These must be done by an experienced veterinarian.
12. When should soaking be done and how often?
    • When there is an open wound the foot can be soaked in betadine and hot water one day, then hot epsom salt water the next. Soaking or turbulation, 10 to 15 minutes per day, when helping to clean up abscess is done until there is no more drainage or suppuration. The foot is treated with sugardine and bandaged daily. Ichthammol can be used on the coronary band to draw abscesses and to keep the coronet soft and pliable. Each case is treated individually. In the case of osteomyelitis the foot should not be turbulated.
13. What should I do when the drainage stops?
    • Merthiolate is used when there is no more drainage. Turbulation and soaking should also be discontinued.
14. What is happening when a severely foundered horse walks on the toe?
    • There are two possibilities:
    • An abscess has formed in the heel area. This is usually best treated by using ichthammol ointment or magna paste around the entire coronary band, to break out the infection.
    • The tendon becomes involved. If this is the case sometimes a tendon desmotomy can be done, with good results.
15. What feed supplement have you found obtainable on today's market which stimulates rapid hoof growth?
    • In the past I used and recommended the amino acid powder, methionine, essential for epithelial cell formation. However useful it may be, many horses found it unpalatable and refused to eat it. Consequently, the internal nutrients needed to build strong hooves were lost. In the late 1970's Life Data Labs began marketing an alfalfa-based equine supplement, FARRIER FORMULA or NUTRI-TONE, which most horses like. This product contains the essential amino acid, methionine, as well as biotin and other nutrients needed to maintain healthy hooves. I have seen a visible difference in hoof growth, within weeks, using this product.
16. How much time is involved in returning the horse to sound pasture condition or performance condition?
    • The cause of the problem must first be corrected. The severity of the problem within the hoof capsule must be evaluated before any decision can be made as to the future of the animal. Sometimes the horse will respond and return within 9 months to a year. The horse must grow a complete new hoof before any favorable commitment should be done. Again, it depends on each individual case and its severity.
17. How often should the shoes be reset?
    • I recommend the shoes be reset every 30 days. In the early stages of treatment and shoeing the heel will out-grow the toe as much as a 4 to 1 ratio. It is essential to trim the feet on a regular basis.
18. Do you recommend pads?
    • No. If PIII sinks inside the hoof capsule the vessels become compressed, the blood supply (arteries and vessels) can be destroyed. I use a rim pad in conjunction with the heart bar shoe. Sometimes this is necessary to clear the distal end of PIII off the ground. Pads which cover the sole cause complications because abscesses must be allowed to stay open for ventral drainage and healing.
19. How long should I leave my horse shod with heart bar shoes?
    • Sometimes for a lifetime. Each case must be treated as an individual. It depends on the severity and condition of each individual animal.
20. What is my responsibility, as owner, after the initial treatment?
    • A commitment must be made of time and money by the owner. It takes months for nature to restore the damaged hoof. Each case is different, but these horses do not get well overnight, therefore require good nursing and after care. I must stress the importance of after care. This care includes resetting the shoes on a frequent basis; rebandaging; exercising; and it often requires regular checkups by experienced farriers and veterinarians. Prompt resetting of the shoes, as needed, can prevent unnecessary problems caused by feet left to grow too long. Depending on the individual horse, bandaging will be needed every few days, which can sometimes last as long as several months. Exercising the horse by daily walking is beneficial in order to obtain the return of overall body mechanics and general well being. This care can be done by the owner, his agent or left in the care of a "treatment center". All of these can be time consuming and expensive.
21. When should I use a heart bar shoe with a rolled toe?
    • In severe rotation cases the toe of the shoe should be rolled in order to take the stress of break-over off the deep flexor tendon. By rolling the toe this moves the fulcrum point posteriorly.
22. How should I control exuberant granulation tissue?
    • In extreme cases cauterization is the best method I have found to control this tissue. This is followed by application of copper sulfate powder and continued until exuberant tissue is below the epithelial cell line.
23. What is a "sinker" or "straight vertical displacement"?
    • A "sinker" is when the PIII is going downward in the hoof capsule. The hoof capsule moves proximally. No rotation is noticed except at the coronary band. This can be easily diagnosed by manually palpating the coronary band. If a distinct depression is noted at the coronary band from heel to heel the result is a "sinker". If the sole is intact then a heart bar shoe can be used in conjunction with a frontal hoof resection and by opening the sole at the junction of the distal laminae and the horny sole. If the horny sole has disintegrated a heart bar shoe should not be used. Instead, a heart bar device made of a thermoplastic material can be substituted.
24. Should the foot be blocked or any kind of pain reliever be used when shoeing a horse for founder or laminitis?
    • No. The horse must be able to feel the support being applied and thus indicating if correct support has been used. The amount of pain is a significant clinical sign. If the laminae are tearing loose and the bone is likely to rotate, it is wrong to mask the signs with pain-killing drugs or nerve blocks. By using pain-killing drugs the horse continues to walk which causes more tearing of laminae hastening the separation of laminae from PIII.
25. What are some shoes and devices that work with very little consistency?
    • The egg bar shoe has no stabilizing effect on the bony column.
    • The reverse shoe gives no stabilization to PIII.
    • The reverse wedge pad places more tension on the deep flexor tendon thus causing more rotation.
    • The hoof cast compresses the blood supply of the venous plexus of the sole, and can cause an osteothrombosis of PIII, and is dangerous for general use.
    • A bar shoe with a bar across the center of the shoe can compress the palmar digital artery, destroying the blood supply to PIII.
    • A pad with packing under it gives no stability to the bony column and frequently causes pressure on the sole, destroying its blood supply.
    • A shoe that raises the heel and takes the stress off the deep flexor tendon aligns all the laminae perpendicular to the ground, causing the bony column to sink.

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