Hip Resurfacing vs Replacement

On the left is an x-ray of a person with a resurfaced him, you can see a metal cap covers the natural femoral head (which is no longer visible because of the metal on x-ray) and a small metal stem extends into the femoral neck. On the right is an x-ray from a person with a traditional total hip replacement where the femoral head and neck are removed and replaced with metal, plastic, or ceramic components. https://orthoinfo.aaos.org/en/treatment/hip-resurfacing/