Total Hip Replacement (THR) or Arthroplasty (THA) surgery restores the articulation mobility and stability by implanting a prosthetic hip joint. The selection and positioning of the implant are critical in this procedure. Conventional planning seeks the optimal selection of implant characteristics by relying on a “static” approach which only exploits anatomical cues derived from a plain radiograph or a CT scan. Dynamic aspects are indeed neglected, such as pelvic tilt during postural changes and the necessary motion of the prosthetic hip to yield a satisfactory range of motion (ROM) in everyday life.
Despite an adequate planning, its execution during the surgical act remains problematic, since intra-operative guidance is not commonly provided. As a result, the effective positioning of implants may significantly deviate from the planning. A post-operative assessment of the prosthetic hip is hence necessary to investigate the quality of the surgery.
Computer assisted navigation systems have been developed as a means to provide more accurate guidance during implantation of artificial hip joints. The advantages of computer-assisted hip surgery are increased accuracy, decreased invasive operations, improved planning and simulation, and reduction in radiation exposure.
This procedure uses three dimensional (3D) computer images to assist the surgeons in complex hip replacement surgeries by combining preoperative planning and intra-operative performance by displaying 3D computer images in relation to patient anatomy and consist of a computer workstation with image processing and surgical planning software, a localization system and a display monitor.
Computer software enables the surgeon to rotate and magnify areas to determine cutting planes and implant position and to measure distances, angles and volumes to provide surgical guidance. Computer assisted navigation involves three processes: data acquisition, registration and tracking. Data can be obtained using CT or MRI systems. Registration techniques use the placement of pins or markers in target zones and tracking uses sensors and measurement devices to provide feedback during surgery.
At the current time however, there are some barriers to computer-assisted hip replacement surgery that include increased operating time, and extensive training of the surgical team. However, this extra time is minimal once the surgeon becomes proficient.
The clinical application of computer-assisted total hip replacement (arthroplasty) is less common and is currently confined to a few surgeons experienced in such techniques. Dr. (Prof.) Anil Arora with years of experience and his inclination towards imbibing and applying newer technologies in joint replacement, is able to perform the computer assisted hip replacement in approximately 60 minutes, which is quicker than some surgeons who perform hip replacement using the conventional technique.