How long does it generally take an arthritic foot to fuse? its been five years so far that's its been trying to fuse.

Maybe never: A arthritic joint will tend to have less range of motion and more stiffness but will not necessarily fuse. Surgery is normally required to fuse a joint. There are are other treatments for arthritis in the foot depending on the location, symptoms and function. See a podiatrist for evaulation and discussion of treatment options.

Unknown: Bone does not heal properly with movement. Depends on which joints are trying to fuse. In the best of circumstances it takes at least 6 weeks for bone to heal after surgery. One would need an x-ray and more information before answering a general question.