I like Worm-slicer's idea that the bone implement could be a cooking or eating tool. In my imagination, I see a spoon like taster, to let the cook check the taste of the food.
It looks like you may have a habitation artifact, more like a midden item, not a tool, but perhaps what was left over from dinner, the obsidian items do look like old stone tools or points, worn down by age and water action
Alan M might be on to something, it could be leftovers from a butchered deer, but I don’t see a tool.
Are bone tools common in your area? They were certainly made and used, but if preservation isn’t right, your odds of finding one are very low. In some areas bone preservation is great, and in some areas bone might only last 20 years or so before degrading to the point that it’s little more than fertiliser. Actual use as a tool polishes the surface of the bone which helps preservation at many sites. Midden bone is often chalky.
The shape. It could very well be a spiral fracture, which can happen naturally on long bones. It could have also happened from human processing a kill to get marrow. It could happen from a big predator/scavenger breaking a leg with a twisting motion. The bite and shake motion that many do to overwhelm prey, to quickly kill prey with massive blood loss, or to tear off a piece from a larger kill can torque a bone enough to do this. In Florida gator bites often include a spiral fracture from the bite & roll motion.
I can’t see clearly but fresh bones break differently than old bones. Fresh ones have a little twist to them called a green spiral break. I think yours might have a spiral break and may have been broken near the death of the animal. Assuming that it was a human kill and a spiral break it was likely broken intentionally either as a tool or to get to the marrow