X-Men2000

[Professor Xavier, Jean, Cyclops, and Storm go over Wolverine's x-ray]

Jean Grey:
The metal is an alloy called adamantium. Supposedly indestructible. It's surgically grafted onto his entire skeleton.

Storm:
How could he have survived a procedure like that?

Jean Grey:
His mutation. He has uncharted regenerative capability, which enable him to heal rapidly. It also makes his age impossible to determine. He could very well be older than you, Professor.

Cyclops:
Who did this to him?

Jean Grey:
He doesn't know nor can he remember anything about his life before it happened.

Professor Xavier:
Experimentation on mutants. It's not unheard of, but I have never seen anything like this before.