The economical and reliable image free navigation system for acetabular cup implantation in total hip arthroplasty

Abstract Introduction: Implantation of acetabular cup is the cornerstone in total hip arthroplasty (THA). Functional outcome of THA is related to acetabular inclination and anteversion besides other parameter like; stability, limb length alignment, capsule closure etc. Various navigation and robotic equipment’s are available to assist the surgeon to place the hip implant in right version. High cost, steep learning curve and safety of equipment has restricted its use less than one percent.Materials and Methods:We have designed an image free navigation device to assist the surgeon to implant the acetabular cup in right inclination and anteversion. The experiment has been performed on an artificial hip bone structure. Historically a total of 50 iteration of the angle measurements were performed to access accuracy of the device. The images from each of the measurement was imported in ImageJ software to find out the actual angle. The principle of openCV is used for image processing in our navigation device.Results:The results of the study found the angle of inclination mean error of 0.15° with standard deviation of 0.44° with a p value <0.05, which is very significant. Similarly the angle of anteversion mean error was -1.06° with standard deviation of 0.34° and p value < 0.05, which is very significant. The tool provides a good accuracy with an error of less than1.5-2 degrees.Conclusion:Our image processing device delivered promising results with regards to acetabular inclination and acetabular anteversion in invitro studies. The tool is compact, can be easily transported in a briefcase and can be used without any extensive training. Besides an initial cost of few thousand rupees, the recurring cost in each surgery is less than 200 rupees. We presume this is the world’s most economical navigation tool which is reproducible and reliable.