1. Robot assisted UKA a randomised trial Justin Cobb Chair of Orthopaedics Imperial College London

2. CT based planning Few 5mm slices through hips and ankles Few 5mm slices through hips and ankles 1mm contiguous slices at knee 1mm contiguous slices at knee

3. Novel registration algorithm  Hip centre  4 initial points  6 points in 5 zones

4. On screen feedback more helpful than direct vision

5. Rest of operation is routine

6. Results  Prospective Randomised Controlled Trial Ethics committee approved Ethics committee approved Conventional mis uka by one of 4 surgeons Conventional mis uka by one of 4 surgeons All had ct based planning All had ct based planning Surgeon showed what he was aiming at Surgeon showed what he was aiming at Patients not told until after 6 week check Patients not told until after 6 week check Imaging reported by blind assessor Imaging reported by blind assessor

7. Post-op CT vs pre-op plan  Whole bone images co- registered White = plan White = plan Yellow = achieved Yellow = achieved Combination of errors:Combination of errors: registration registration bone prep bone prep implantation implantation

8. Control examples cases 1,3

9. Control Group

10. Acrobot example 1

11. Acrobot Group

12. Blind assessment Difference in stdev 2 times 3 times 1.5 times 2.5 times 3 times

13. Acrobot much more accurate Tibio- Femoral angle Type of surgery All knees Acrobot System Conventional   2° 13 (100%) 6 (40%) 19 >  2° 9 (60%) 9 Total 131528  P<0.001 (Fischer’s exact t test)

14. Correlate accuracy and AKS scores Correlation is significant, p=0.002

15. Summary 1MIS UKA will become the default operation for OA of the knee, whether medial, lateral or patello-femoral 1MIS UKA will become the default operation for OA of the knee, whether medial, lateral or patello-femoral 2 Meniscal bearing an excellent option 2 Meniscal bearing an excellent option 3 Ct based modelling is an enabling technology 3 Ct based modelling is an enabling technology