What occurs during a bone fusion surgery?

Fusion (Arthrodesis): The technical term for fusion is arthrodesis. It's commonly used in the spine and joints like hip, knee and ankle. When joints become arthritic and lack cartilage, it's very painful to have bone rubbing on bone as 2 independent surfaces. Fusion attempts to bridge the two surfaces by using bone graft and other biomaterials. Once the surfaces heal together, there's no motion and this reduces pain.