What are the long term consequences of a shattered pelvis?

Depends. Ive seen people return to completely normal lives, others have chronic pain. People who dont give up and keep pushing to get stronger, usually do better.
Variable. This one really depends on how bad was the fracture, where in the pelvis was the injury, and was this repaired surgically. But in general this can be a bad injury and can lead to chronic pain, some degree of disability and potentially post traumatic arthritis if the fracture involved the hip joint (acetabulum).