Minimal printable cupholder / canholder designed to be printed in one piece without support. Bolts through the unused holes in the crutch using 1/4-20 hardware. I have not tested this design with an actual set of crutches so it may require additional modifications. You'll probably need to customize your own design to configure the diameter of your crutch tube and the diameter of the opening for the cup. You can access the original parametric design in Onshape (https://cad.onshape.com/documents/82ad17b007a94613841d6972/w/64cdf7020bb64706aea49f5d/e/c2d608f07771465899628a07)
The main parameters you're likely to modify, the cup diameter, crutch mount diameter, or the gap in the hinges are labeled in all caps. But feel free to modify in other ways. The different versions are stored in separate branches, the small cupholder is in the main branch.