In my mind he was probably bound by the chains when he was modified. Upon re-activation he moves and breaks free from the chain. The cuffs remained on his wrist and is now part of his appearance. His physical self has broken free but his conscience is still bound to Shocker.
Honestly, I really like the cuffs and the chains hanging from the wrist. I dunno why but it's aesthetically pleasing. It's a nice way to incorporate the Shocker symbol in his design as well.