The document discusses the role of computer assisted surgery (CAS) in orthopedics. It notes that CAS aims to improve implant longevity, reduce human error, and simplify surgical techniques. While CAS can increase accuracy, early systems were too troublesome with complex feedback and safety systems. The document examines studies on the benefits of CAS for total knee arthroplasty, finding it can reduce outliers but does not clearly provide better patient outcomes. Large sample sizes are still needed to detect small differences. Accuracy depends on multiple factors introducing errors. While CAS aims to benefit patients, early techniques also increased costs and surgery time. [/SUMMARY]

1. Søren Toksvig-Larsen Dept Orthopedics Hässleholm Hospital Lund University Sweden The role of computer assisted surgery (CAS)

3. WHAT’S WRONG WITH THIS SCENARIO 2007?

6. My background Istituti Ortopedici Rizzoli EU projects

7. CAOS Computer Assisted Orthopaedic Surgery

8. Robot surgery ” active”

9. Formula 1 Robot surgery

10. 3-D op technique

11. Problem Too troublesome Feed back systems Safety systems

13. Why continue using modern technique??

14. Who is a non-responder My problem Non responders

17. Navigation “ passive” Surgical set up

18. Navigation gives information during surgery to position the instruments and implants according the “anatomy”

19. Knee Navigation workflow HIP center

20. Knee Navigation workflow

22. NAV as other computers ” shit in, shit out”

23. Record Alignment

24. More sophisticated instruments

25. Tibia cut

26. Gap balancing/tension ?????????????

32. OVERALL SYSTEM ERROR  2 mm the average difference between point distance in the virtual scene and the corresponding point distance in the real world, is given by: ACQUISITION ERROR:  1 mm errors in surface position produced by the segmentation algorithm SIMPLIFICATION ERROR: 0.4 mm ACCURACY OF THE TRACKING SYSTEM:  0.5 mm REGISTRATION ERROR:  1 mm ACCURACY OF THE POSITION SENSOR: 1.0 mm defined as the standard deviation of a set of measures with respect to the “real” value, obtained by means of a calibration instrument.

33. Intraoperative cutting errors Some of my experience using navigation Pinning the cutting block can change the position of the block 1 - 2 degree The cutting process can change the surface additional 1 - 2 degree Can partly be corrected using navigation

35. z Alignment – outliers (2-D) Femural component too extended valgus positioning the femural component Less bloodloss Individuality Tibial rotation