I saw a display in the Smithsonian a few years back that showed some of the skeletons from an early colonial town in what is now the eastern US. Some of the people had broken bones that had healed without being properly set, but their limbs didn't heal straight. They looked worse than
these healed bones from the Roman era. There was at least one skeleton who had had a bone infection that they'd recovered from, but it left permanent damage. There's little question that these people were disabled for the rest of their lives, and likely experienced chronic pain.
You know how they set someone's broken leg or arm in books and TV shows that take place in the old days? They get the person drunk maybe, and pull the limb straight, and they pass out, but it heals okay after it's splinted? That's not a likely outcome, except with the cleanest and least displaced breaks. There's a reason why, in the earlier 20th century, they put people in those traction apparatuses, and today they often put pins or plates in broken bones to get them to heal right. There were relatively skilled surgeons, even back then (and they had interesting devices for producing traction, even in the renaissance), but the lack of safe and effective anesthetics and disinfectants made surgery on broken limbs (and the outcomes of compound fractures) rather iffy.
I'm guessing a person with shattered kneecaps would survive, but they'd be unable to bend their knees after. And they'd be in excruciating pain for quite a while. Even the initial inflammatory and soft callus formation process of bone healing can take weeks to resolve (and that's just the start of healing), so I don't see this person flying an airplane or doing anything else that requires much movement of their limbs.