It is always more difficult to splint a dog's broken leg than a humans', solely because communicating to an injured dog is not possible. Many dogs will react violently when in pain, so take caution even if the dog is your own by using a muzzle or tying the dog's muzzle. If the dog is not your own, approach carefully. If possible, take the dog to the vet immediately upon injury, but if substantial transport is necessary to get to the car, then splinting prior to moving is highly recommended.
Splinting a dog's broken leg
Examine the fracture. Broken bones do not necessarily show on the outside, and it might be a sprain. If a fracture is suspected, then calm the dog down and find a tie or muzzle to ensure your own safety first. Do not allow the dog to move. If it is the front leg, simply use two sticks or any straight and stiff material and tie the splints securely to the dog's front leg and carry him to the car for transport. If it's a hind leg, follow the directions below.
Refrain from straightening the bone if the fracture is visible. The objective of splinting is simply to keep the broken bone immobile during transport to prevent further damage. Manipulating the bone can result in greater tissue damage, or worse, puncturing of vital arteries, leading to sudden and immediate death.
Wrap the entire leg with cotton roll, if possible, making sure not to move the broken bone. If an external wound is visible, gauze can be added prior to wrapping. Once several layers of cotton roll have been applied, wrap the entire leg in stretch gauze securely. Take care not to wrap too tightly in order to maintain proper circulation. This step, if in the woods or material is not available, can be skipped.
Find wire hangers to act as supports and twist to create the shape of the dog's broken leg. During this process, make sure you do not move the dog's leg, and adjust the wire hanger away from the injury. Once the desired shape is achieved, gently place next to the entire length of the leg. The hangers will serve as the splints.
Secure the wire hangers into place with bandages or a large cloth cut into strips to use as ties. If none are available, then tape can be used. If you have skipped step 3, it is highly suggested that some type of padding be used under the tape to prevent the tape from sticking to the dog's fur, especially if duct tape is all that is available. Using tissues under tape would be better than nothing at all. This is to prevent additional pain to the dog when the tape is removed, but also to enable veterinarians easier access once the dog arrives for veterinary care.
Transport the dog to the car. Depending on your location, this can be tricky. If you are a good distance from your car, and someone else is around, then ask for help to keep the dog as still as possible. If you have access to a large board to carry the dog, it is highly advised that you use it. If the dog is too large and cannot be carried safely to the car, it's best to use a sheet or towel. Place the entire dog onto the material and drag the dog slowly to the car. However you transport the dog, keep the broken leg as still as possible.
Drive directly to the veterinarian. No matter how careful, it's possible that the process of splinting has damaged the broken leg, making a small fracture into a complex or complicated fracture. A dog with a broken leg needs immediate medical care in order to stand any chance of saving the leg. Once at the veterinarian's office, do not attempt to carry the dog inside. Go inside the office and request transport help for the dog.