The article said laminitis. Here are some of the causes of laminitis:
2.1 Carbohydrate overload
2.2 Insulin resistance
2.3 Nitrogen compound overload
2.4 Hard ground
2.5 Lush pastures
2.6 Frosted grass
2.7 Freezing or overheating of the feet
2.8 Untreated infections
2.9 Colic
2.10 Lameness
2.11 Cushings disease
2.12 Peripheral Cushings disease
2.13 Retained placenta
2.14 Drug reactions
2.15 Exposure to agro-chemicals
This means that the injury was brought on by his race-horse lifestyle -- too many carbs, overly-rich hay (they feed race horses hay which is 26% protein as opposed to the 12-14% we use), drugs, perhaps even freezing of the foot to resist pain.
But it's a very common sequela of severe leg injury to develop laminitis in the opposite foot. In fact if a horse survives an initial broken bone but is ultimately destroyed, foundering and tilting of the coffin bone in the opposite foot is usually the reason.
The technical veterinary term is laminitis because the laminae or layers of horn in the hoof become inflamed and separate, but around the barn it's almost always known as founder. Once the coffin (navicular) bone tilts, it's usually over, but it looks like with Barbaro they are going to use some sort of therapy to re-align the bone. That's way above my pay grade, or the pay grade of any horse I ever had anything to do with . . .
Interesting sidelight -- I worked for an old-timey equine vet who believed in bleeding in cases of founder. He would open a vein in the foundered leg -- it did seem to work, I wonder if anybody's done any studies on that.
My mistake - the coffin bone is technically the pedal bone, not the navicular bone. The navicular is the little bone higher up above the pedal bone - and with T'breds the cause of much trouble for other reasons but not usually involved in cases of founder.