(1) Computer Science Department, The Johns Hopkins University, Baltimore, MD, USA
(2) Institute of Computer Science, The Hebrew University, Jerusalem, Israel
(3) Integrated Surgical Systems, Davis, CA, USA
(4) IBM T.J. Watson Research Center, Yorktown Heights, NY, USA
(5) Berufsgenossenschaftliche Unfallklinik, Frankfurt am Main, Germany

This paper describes an ongoing project to develop a computer-integrated system to assist surgeons in revision total hip replacement (RTHR) surgery. In RTHR surgery, a failing orthopaedic hip implant, typically cemented, is replaced with a new one by removing the old implant, removing the cement, and fitting a new implant into an enlarged canal broached in the femur. RTHR surgery is a difficult procedure fraught with technical challenges and a high incidence of complications. The goals of the computer-based system are the significant reduction of cement removal labor and time, the elimination of cortical wall penetration and femur fracture, the improved positioning and fit of the new implant resulting from precise, high quality canal milling, and the reduction of bone sacrificed to fit the new implant. Our starting points are the ROBODOC system for primary hip replacement surgery and the manual RTHR surgical protocol. We first discuss the main difficulties of computer-integrated RTHR surgery and identify key issues and possible solutions. We then describe possible system architectures and protocols for preoperative planning and intraoperative execution. We present a summary of methods and preliminary results in CT image metal artifact removal, interactive cement cut volume definition and cement machining, anatomy-based registration using fluoroscopic X-ray images, and clinical trials using an extended RTHR version of ROBODOC. We conclude with a summary of lessons learned and a discussion of current and future work.

Keywords: Computer-assisted surgery, orthopaedics, revision total hip replacement, image-based registration, ROBODOC and ORTHODOC systems.

Medical Image Analysis, Oxford University Press, Vol 1(2) 1999, pp 1-19.