Yes, there are many DPM's that have travelled all over the world to perform surgery on the less fortunate. There is the Baja Project in Mexico and similar "missions" all over the globe. The majority involve reconstructive surgical procedures for children, often to correct clubfoot or similar congenital deformities.
For more information you may want to contact the APMA. The trips are usually paid for by the doctor who will often raise money via fundraising, etc., or an organization will sponsor the trips.