For a simple colles fracture, why so long before return to play?

Distal radius injury: Much depends upon what you mean by "simple" and play. Do you mean a fracture of the radius in an adult that was reduced in the er and now is casted and "play" means boxing . Or do you mean a ten year od with a buckle fracture who wants to play recreational town soccer? "simple colles fracture' can mean a lot of different things, and this is why most orthopedists and hadn surgeons hate eponyms.

Depends: For a simple colles fracture, once casted you can play in the cast. Generally, you will be casted for around 6 weeks then allowed to be cast free but likley restricted from sports for an additional few weeks until you have restored normal motion and function to the wrist joint. Depends on fracture: bones take atleast 6 weeks to heal and the joint a few weeks to regain its flexibility and function.