Is it recommended to get joint replacement or fusion for arthritic hands?

Depends on joint: Distal joints need stability and proximal joints need mobility. The knuckle nearest the finger tip is usually fused, with good results. The knuckles nearest the hand can be replaced. Some arthroplasties utilize tendons or other soft tissue, others use silicone or metal and/or plastic. See a board certified orthopaedic hand surgeon for evaluation and treatment.