Acrotomophilia

You have to already be afflicted with the syndrome of acrotomophilia (which has its genesis in childhood) in order to be turned-on by amputation stumps.

Although there is no adequate explanation of the etiology of acrotomophilia, evidence points to a developmental onset in early childhood...

...the fetishistic attachment is not to an object but to a part of the partner's body, for example the hair or, in the case of acrotomophilia, the stump of an amputated limb.