COMPUTER AIDED NAVIGATION IN TOTAL HIP REPLACEMENT ARTHROPLASTY: TECHNIQUE AND ACCURACY

Abstract

Computer aided joint replacement surgery is being used increasingly. It is more commonly used at present in the knee replacement surgery as compared to hip replacement arthroplasty. It is still under developmental phase. The published literature shows there is increased accuracy of the component placement of acetabular cup and femoral stem. We describe the technique for the Stryker navigation system as used in total hip arthroplasty.

The technique used by us presently is an active tracker system. This is a both way communication system of infrared waves between the trackers and the sensors. The trackers are fixed to the bones, then the registration of patient specific anatomy is done and hip arthroplasty is performed with aid of the computer navigation.

The computer navigation gives the values of the component orientation in space. It gives the implant position in the pelvis and femur models generated by the computer but fed in and created by the surgeon. It is important that the data fed to the computer in making the model of pelvis and femur is accurate. It is surgeon dependent. At the end of surgery one can also evaluate impingement and range of motion. It also shows the change in offset of the centre of rotation of the hip as well as leg lengthening. While it can aid in the technical performance it is essential that the surgeon does not go blind to his operating environment as the computer navigation is to help the surgeon, not replace.