From: kris@boi.hp.com (kris troxel)
Newsgroups: rec.equestrian
Subject: ringbone
Date: 16 Oct 92 16:02:23 GMT
Organization: Hewlett-Packard / Boise, Idaho
X-Newsreader: TIN [version 1.1.4 PL6]

I have been meaning to post on this subject all week, but I kept forgetting
to bring in my "bible" on lameness. I have a copy of Dr. O. R. Adams
Lameness in Horses, 3rd edition. There is a 4th edition out but I haven't
been able to bring myself to spend the $250 to buy it. My copy was an X-mas
present so I really appreciate it. It is used as a text book at most vet
schools on this subject, so I tend to really believe what it says. If anyone
is interested in the publisher, etc. just let me know.

Ringbone (Phalangeal Exostosis)

Definition - Ringbone is new bone growth that occurs on the first, second, or
third phalanx. It is the result of a periostitis and may lead to an osteo-
arthritis or ankylosis of the pastern or coffin joints. This condition is
seldom found in Thoroughbreds but is relatively common in other breeds.
Ringbone is classified in two ways: High or Low Ringbone.

High Ringbone: This is new bone growth occuring on the distal end of the
first phalanx and/or the proximal end of the second phalanx.

Low Ringbone: This is new bone growth occuring on the distal end of the    
second phalanx and/or the proximal end of the third phalanx, especially
at the extensor process of the third phalanx.

Articular or Periarticular Ringbone
Articular ringbone: This means that the new bone growth involves the joint
surface at the pastern or coffin joints.

Periarticular ringbone: This means that the new bone growth is around the joint
but does not involve a joint surface. it is most common in high ringbone.

Etiology: Trauma is the usual etiology of ringbone. He talks about stress
and pulling of the collateral ligaments attached to these joints, which
causes inflammation of the periosteum (covering of bone) and new bone growth
results. Fractures of one of the phalanges will also cause ringbone. Poor
conformation may predispose to pulling of the collateral ligaments, joint
capsule, and tendon insertions. Horses that are base-narrow and toe-in or
toe-out are predisposed to ringbone on the lateral side of the joints, 
while horses that are base-wide and toe-in or toe-out are predisposed to
ringbone on the medial side of the joints because the foot and leg con-
formation exerts greater stress on these areas. Ringbone is considered to
be inheritable by some authors, but it is probably inheritable through poor
conformation. Pasterns that are overly upright will result in increased
concussion to the pastern joint. The inheritability factor would not affect
all forms of ringbone, because some result from trauma. Poor conformation
increases stress on ligamentous and tendinous attachments to the phalanges
and may cause ringbone resulting from an osteoarthritis caused by uneven
pressures on the articular surface.


Treatment: He says treatment depends on the cause of the ringbone. If it
is caught in the early stages limiting motion by casting is a good method.
Injection of a corticoid into the joint is also helpful. He also suggests
blistering, surgical removal of cartilage and bone spurs, and shoeing tech-
niques. He also says that neurectomy is sometimes preformed to remove the
pain. He goes on to describe the advantages and disadvantage of "nerving"
and says that it usually has poor results.

Prognosis: The prognosis is always unfavorable if the ringbone is articular.
It is gaurded if the ringbone is periarticular

I hope this helps, though it might be real confusing. This book has been
very helpful, but always leads to discussions with my vet for clarification
and also to find out if anything "new" is being used. If anyone would like
more info, or more specific quotes let me know.

Kris Troxel
Shezza Brat, AQHA, Working Cowhorse extraordinaire. 
Newsgroups: rec.equestrian