I am a 20 year old with an entire metallic femur, knee and hip bone due to childhood cancer. I was the second person in the world to have this technology.
I was diagnosed with Ewings sarcoma at the age of 9. The only way to save my leg was to replace the infected area, my femur, all the way up to the knee with a metallic prosthetic replacement, which you can see here: http://i.imgur.com/XEfFVPV.jpg Or a close-up: http://i.imgur.com/Gvnsdp6.jpg
I've actually just had the prosthetic extended to my hip 3 days ago. I'm writing up this AMA in my hospital bed right now. I had to have it extended after I fell over and fractured the bone surrounding the previous prophetic. The only way to fix it was to replace the hip by extending the prosthetic.
Fracture here: http://i.imgur.com/6T2DkJG.jpg
Here is a comparison of my two legs, the operated leg usually looks a lot more skinny. It's still swollen from the operation: http://i.imgur.com/VGFm0aK.jpg The original scar went up to my thigh, you can see from the dressing how they extended it
Edit: Just got my discharge date, planned for the 5th of august! Thanks for the questions and lovely comments