An X-Ray is necessary, of course. All species have the ability to heal their broken bones with the proper stabelization, and depending on the type of fracture. Most local zoo's and wildlife rehabilitators have veterinarians that treat their animals. Call a zoo or wildlife rehabilitator to see if they can help.
Yes, a large bird like a vulture can have the bones pinned but it must be done by a vet with avian experience. What concerns me is you say the break is "between the joints." Do you mean the break is separating the joints (at the elbow for example) or it's the bones between joints like the wrist and elbow (the radius and ulna)? That would make a difference. If there's a break at a joint, it may heal but the bird will lose all mobility in that joint. In a wing, that means the bird will never fly again. Then the bird either has to be placed in permanent captivity in a licensed facility for educational purposes or euthanized. That's the federal law.
Is any of the bone exposed? That's another problem since it leaves an opening for bacteria. Please get the bird to a wildlife rehab center or check with your local vets or zoo to get treatment ASAP. Depending on the break, the longer it goes without treatment, the more damage is done to bone and surrounding tissue.
You don't mention which state you're in. Otherwise I could try to find a center near you. Unfortunately, I'll be gone most of the day and the bird needs help now. Good luck. Check with the vets, the zoo and your state fish and wildlife department. One of them should be able to point you in the right direction.