3 yr old son broke his tibia and still limps - should my husband be so worried about his future development?

Following a fall down a 20 meter drop in a sledge, he broke his tibia (non displaced fracture) - (thank goodness that's all it was). 2 weeks in plaster, now 4 weeks out of plaster - he's had 5 physio sessions. The physiotherapist seems happy that he's done enough, but he's walking now with his foot turned out and limps. My husband feels that his footballing and skiing career are over!! but seriously is worried that he will never walk 100% properly again - is this really a possibility? What can we do about it?