1. Partial Surface Replacement 5 to 14 Years Results T. JUDET T.SIGUIER J-L.MARMORAT P.PIRIOU B.BRUMPT M.SIGUIER Raymond Poincaré Jouvenet IMK 2006

2. Osteonecrosis mainly affects young patients: How to avoid THR? Core decompression Cancellous bone grafting Vascularized bone grafting Intertrochanteric osteotomies Rotationnal basi- cervical ostéotomies

3. Drawbacks, limits and failures of conservative surgery Technically over-demanding procedure Long lasting rehabilitation Unpredictable results Controversial efficiency Major anatomical disturbance of the upper femur

4. Partial resurfacing concept Marc Siguier 1990 Minimalist design and operative technic Replacement anatomically limited to the pathologic area Preservation of the hip anatomy Preservation of the mecanical properties of the femoral neck

5. The MMS Implant 120° Covering area Range 40 to 60 mm diameter to match the exact sphericity (2mm increment) Dedicated instrumentation for each size Cemented fixation

6. Surgical technic Anterior approach on fracture table T-shaped capsulotomy Anterior dislocation preserving circumflex vessels Excision of the ostéochondral collapse and under-lying loose necrotic bone

7. Surgical technic Measurement of the femoral head Preparation of the prosthesis setting in line with the center of the head

8. Surgical technic Trial implantation without tilting and flush or beneath the surface of the healthy remaining cartilage Cementation of the definitive prosthesis

9. Post operative care Immediate rehabilitation and full weight-bearing

10. Interrogations and potential problems Quality of bone-implant fixation Evolutivity of the pre-OP necrotic area Post-OP extension of the necrotic area toward the pre OP limits Cartilage tolerance to the implant and further degenerative changes

11. Previous published results Siguier M, Judet T, Siguier T & al J.Arthroplasty 1999 Preliminary results of partial surface replacement of the femoral head in osteonecrosis 25 procedures 6 failures (FU 20-60 mths) Siguier T, Siguier M, Judet T & al Clin. Orthop. 2001 Partial resurfacing arthroplasty of the femoral head in avascular necrosis Methode, indication and results 37 procedures 9 failures (FU 24-89 mths)

12. Actual Serie Continuous Serie April 1991 - Jan 2001 61 MMS procedures (54 patients) Age 42 years (24 - 59) 45 Males et 9 females Aetiologies Post trauma 6 cases Steroïds 11 Cases (9 patients) Alcool/tobacco 7 cases (5 patients) Idiopathic 35 cases (32 patients)

13. Clinical Pre- operative Status Postel Merle-d’Aubigné score 12 pts (8 - 17) Pain 2,3 pts (1 - 4) No preventive surgery

14. Radiological Pre-operative status Ficat & Arlet Staging –Stade II : 1 case –Stade III : 41 cases (67 %) –Stade IV : 19 cases (31 %)

15. Radiological Pre-operative status Evaluation of the necrotic area size after M.Kerboul -Angular measurement on AP view and Lequesne false profile view Mean angle AP : 121° (70 to 180) Mean angle Profile : 116° (50 to 180)

16. Radiological Pre-operative status Evaluation of the necrotic area size -Max depth of the necrotic area; 4 zones to define superficial or deep involvement Stage 2 : 28 % Stage 3 : 53 % Stage 4 : 19 %

17. Results : 56 over 61 implants 1 deceased (2 hips) and 2 patients (3 hips) lost to FU before 5 Yrs Implant removal : 31 cases Implant still in place : 25 cases

18. Results : Implant removal : 31 cases -early technical failure -extension of the necrotic zone - head collapse

19. Results : Implant removal : 31 cases -sinking of the implant -joint line narrowing and degenerative changes No difference statistically significant : failure vs Ficat staging Difference statistically significant : failure vs depth (p < 0,01)

20. Relatively correct bone/implant stability

21. Survival curve End point : implant removal

22. Second look surgery THR through the same mini invasive anterior approach Resurfacing arthroplasty No difficulty related to the previous surgery

23. Conclusion Optimistic : for 25 patients 40 yrs old, improvement lasting 8 years (5 - 14,5) with a pain scoring rising from 2,3 to 5,1. No deleterious effect on secondary procedure Realistic : survey curve 50 % à 10 years 46,5 % à 14 years

24. Conclusion Prospective in the up to date context of mini-invasive surgery, mini-implants are highly attractive and our long term experience of partial hemi resurfacing of the femoral head must render any surgeon very prudent concerning analogous procedures.

25. Conclusion ?

26. THANK YOU MERCI