The topside has been exposed to the sun, rain, snow, and frost for some time and is very weathered. The first action is to add as much glue as possible to save what is left. As is visible, some pieces are missing, and part of the inner bone is visible. I could only find some of the missing pieces, the rest must have been washed away by the water.
After digging a small trench around the bone, we wrapped it in thick aluminium foil and fixed it with duct tape.