X-rays can show up most (but not all) conditions affecting the bony structures of the joints, limbs and spine, and some soft tissue structures as well. I am often asked why vets need to heavily sedate or anaesthetise an animal for this. For the x-ray to provide as much useful information as possible, your pet must be still during the process. Modern anaesthetics are very safe, and most practices now have a nurse monitoring the animal under anaesthetic constantly. Trying to interpret a poor x-ray can sometimes be just as dangerous as guesswork. So, if your vet recommends anaesthetising your pet to x-ray him, there are good reasons why this is helpful in confirming a diagnosis.
Blood samples are useful when looking for increased white blood cell count for supurative arthritis, Rheumatoid factor, and anti nuclear antibody for auto-immune mediated arthritises.
Ultrasound is of limited use as far as the bodies bony structures go, as ultrasound waves only penetrate the bone very shallowly.
Arthroscopy - a tiny camera inserted into the joint - a little more specialized, but becoming more prevalent these days. Can show changes in the cartilage which may not show up in x-rays, because cartilage is not mineralized with calcium.
Contrast radiography - a dye opaque to x-rays is injected into the joint, and an x-ray taken. This could show up particles of cartilage broken off from the joint surface - or "joint mice" as they are otherwise known.
This is not a comprehensive list of diagnostic techniques, but covers most of them currently used in modern veterinary medicine. Next time I'll start discussing the treatments currently used in conventional veterinary medicine.
Rimadyl and other NSAIDs
Rimadyl is a nonsteroidal anti-inflammatory drug. It is similar to drugs like aspirin and ibruprofen. While it is quite effective at treating the pain, it does absolutely nothing to treat the disease or rehabilitate the joint. Furthermore, it has potentially lethal side effects.
Glucosamine is very promising in the treatment of arthritis and hip dysplasia pain in cats, dogs, and horses. Tests have shown it is effective in easing the pain and assists in rehabilitating damaged cartilage.