This is a case report of the release of an elbow ankylosed by post-head-injury heterotopic ossification. An extensive bony resection and soft-tissue release was required. At surgery a pathological, osteoporotic fracture of the radial head was found that could not be preserved and thus was removed. In its place an articulated "floating radial head prosthesis" was used that allowed immediate rehabilitation and avoided the need for temporary joint distraction or stabilization. The initial excellent function achieved has been maintained, at a > 3-year follow-up and without the complications experienced with silicone radial head prostheses.