A 43-year-old man underwent revision of a loose total elbow arthroplasty in 1995. The arthroplasty had been implanted 20 years previously for post-traumatic osteoarthritis after a gunshot wound complicated by permanent ulnar nerve palsy. The patient suffered a minimally displaced periprosthetic fracture 4 years after implantation that was treated closed. The patient subsequently developed severe loosening with bony dilation. During revision surgery, while grasping and removing the periprosthetic membrane from within the humeral medullary canal with a Kerrison rongeur, dorsiflexion of the wrist and hand occurred. Close inspection of the membrane revealed that the radial nerve was encased inside the bone. Although not divided, the traction and contusion of the nerve caused a radial nerve palsy that partially resolved by 4 years of follow-up.