Hypertrophic osteodystrophy causes lameness and extreme pain in young growing dogs, usually of a large breed.
Great danes, German shepherds, dobermans, retrievers and weimaraners are examples of breeds that may be affected by this condition. It appears to occur in weimaraners as a vaccine reaction and this may also affect mastiffs and great Danes. In this case, it usually occurs a few days after vaccination and may appear to be worse than the "average" case on radiographs.
HOD usually shows up as an acute lameness, often seeming to affect all four legs simultaneously. Affected dogs may stand in a "hunched up" stance or refuse to stand up at all. They may have a fever but this is not consistently present.They usually have painful swellings around the lower joints on the legs. Some puppies will die from this disease, some suffer permanent disability but many recover later. The disease is so painful that many owners elect to euthanize the puppy rather than watch it suffer, despite the reasonably good chance for recovery, long term. Affected dogs may be so ill that they refuse to eat.

X-rays confirm this diagnosis in most cases. There are very typical X-ray changes, although it can look a little like bone infection from a septic condition. There is some evidence at this point that viral or bacterial infections may underlie some cases of HOD as canine distemper virus has been found in the affected areas in some dogs. There can be high white blood cell counts and the alkaline phosphatase level in the blood stream is often elevated.

There is also a theory that this condition may occur with excessive dietary levels of calcium or protein. I am not sure what the current status of this theory is.

Treatment usually consists of analgesic medications such as aspirin or carprofen (Rimadyl Rx). Since a viral or bacterial agent may be involved in this problem the use of corticosteroids is questionable. Many people try switching to a diet that is lower in calcium (the puppy foods for large dogs may be a good choice now that they are available. Previously many people switched to adult dog foods which didn't always result in lower total calcium in the diet). Even more potent pain relief medications may be indicated in some puppies. Hydrocodone and aspirin may be a more effective combination than either one alone. Antibiotics are often given for this condition. There is a persistent rumor that vitamin C supplementation is beneficial in dogs with HOD. This appears to be a false rumor and there is some evidence that vitamin C may actually promote abnormal calcification in these puppies. It is not a good idea to supplement vitamin C.

Hypertrophic osteodystrophy may resolve spontaneously in as short a time as a week or so. It can be a recurrent, cyclic infection that goes on for a long time, too. If there are severe secondary bone changes, surgical correction of these may be necessary for normal future function of the limbs.

There is no reason not to control pain as effectively as possible with this condition. That definitely needs to a primary goal of treatment.