Hull Medical Engineering (HULMEC) group was established in 1992 as a collaboration of orthopaedic surgeons and various research groups from the University of Hull to promote multidisciplinary research especially the application of computers to aid in surgery. With the joint effort of researchers and surgeons CAOSS was developed. The key aim of the CAOSS has been to use intra-operative surgical planning using fluoroscopic based images, hence this system aids in performing those procedure which requires fluoroscopy namely dynamic hip screw guide wire insertion, distal locking of the screw and placement of cannulated hip screw. The major steps of CAOSS are the precision calibration of the fluoroscopic images, use of these images for accurate intra operative surgical planning, innovative planning algorithms, and a safe, rapid and accurate approach to trajectory execution. CAOSS has been used on the plastic bones in the laboratory setting and was found to be accurate. Presently CAOSS has been used in an ethically approved clinical trial for guide wire insertion for the DHS placement. Perceived Advantages of CAOSS Safe Passive system Non-invasive Surgeon maintains decision making Decreasing radiation exposure Reducing complexity of the procedure Reducing technical failures Reducing operating time Improving accuracy of implant placement Reducing bone damage (by reducing repeated guide wire insertion) Improving Patient outcome Cost Effective Easy to use