COMPUTER-ASSISTED MEASUREMENT OF CUP PLACEMENT IN TOTAL HIP-REPLACEMENT

The introduction of image guided systems in total hip replacement surg ery provides the ability to plan precisely the alignment of the acetab ular cup before surgery, and to perform the surgery according to the p reoperative plan. Preoperative planners (interactive computer programs for surgical planning) based on three-dimensional medical images allo w planning of optimal placement of implant components based on simulat ed implant performance, Exact measurement of the cup position during s urgery allows precise placement of the cup and accurate measurement of the final position of the cup relative to the pelvis, This measuremen t is used to evaluate the radiographic techniques for postoperative me asurement of cup alignment, Malposition of the acetabular component in creases the occurrence of impingement, reduces the safe range of motio n, and increases the risk of dislocation and wear, Dislocation of the implant after total hip replacement remains a significant clinical pro blem, Not fully understanding the interaction between pelvic orientati on and final acetabular cup alignment may be one of the main contribut ing factors in the continued significant incidence of dislocations aft er total hip replacement. In this study an attempt was made to link th e preoperative planning, intraoperative placement, and postoperative m easurement of cup placement in total hip replacement using computer as sisted techniques.