1. Hospital for Special Surgery Weill Medical College of Cornell University New York, New York

2. Disclosure Research Support: National Institutes of Health NIH/NIAMS R01-AR056802 NIH/NIBIB R01-EB000744 OREF OREF Career Development Award Smith and Nephew Consultant: Smith & Nephew

3. Dual Mobility Modular cup – Polyethylene liner 2 points of articulation – CoCr insert – “Ingrowth” cup Multiple points of fixation  Head:Neck ratio  Jump distance  Stability?

4. – 2 yrs – 79 Cases 1.3% Dislocation 0% Revision rate for dislocation 2.7% mechanical failures Saragaglia et al 2013 – 29 Cases revised for instability – Average FU- 46 months – 1 Redislocation International Orthop (SICOT) 2014

5. Swedish Registry- Hailer et al – 2012 – 228 pt with recurrent instability – Lateral and Posterior approach – Mean FU 2 years (0-6 yrs) – 8% Revision rate for any reason – 2% Revision rate for dislocation

6. What are the short term complications after revision THA with a MDM prosthesis?

7. Methods Hospital for Special Surgery implant billing database – Implant liner part numbers All sizes – All cases reviewed Case coding Chart PACS

8. Methods 379 Cases – 244 Primary THA excluded – 1 excluded Implant billed MDM not implanted 134 Hips – 132 patients

9. Inclusion Criteria All THA revisions with MDM prosthesis (2011-2013) – Acetabular revisions – Stem & acetabular revisions – Liner exchanges only Existing cup compatible with Co-Cr liner – Fusion conversions – Conversion of previous hip fracture Hemiarthroplasty Hip screw/DHS IM nail

10. Methods Hospital & Clinic Charts reviewed – Further Revisions/Procedures Open Revisions Closed Reductions – Issues related to prosthesis – Issues related to revision procedure (complications not related to prosthesis) Patient contacted by phone – <6 months of follow up (<6 months f/u was not an exclusion criteria )

11. Methods Dislocation or prosthesis related failure counted as end point Pt with multiple dislocations after revision were counted as 1 failure

12. Results MeanMinMaxStd Age65.529.097.012.7 BMI27.417.247.35.7 Length of Followup (months after revision) 16.903710.8 LeftRight 6173 Operative Side

13. Results Indication for RevisionNumber Instability5238.8% Acetabular Loosening1813.4% Post Traumatic (DHS/Hemi/Nonunion) 139.7% Acetabular Osteolysis139.7% Replant (Infection)118.2% Poly Failure/Wear53.7% ALVAL53.7% Failed Resurfacing53.7% Femoral Failure42.9% Indication Unclear42.9% Fusion Takedown21.5% Heterotopic Ossification21.5% 134100%

14. Results Number of Previous Surgeries Number of Patients 18261.2% 22518.7% 3118.2% 421.5% ≥564.5% Info not available86% 134

15. Results ProcedureNumber Cup Revision9369.4% Both Component Revision 2216.4% Replant after Infection118.2% Conversion of Previous Hip Surgery to THA 32.2% Liner Revision32.2% Revision to Total Femur21.5% 134

16. Reoperation rate 17 (13%) Dislocations/Cup Failure – 14 (10%) Dislocations 4 dislocations with + infection 1 sciatic nerve palsy after dislocation 1 Intraprosthetic disassociation 1 successfully treated with a closed reduction – 13/14 require open reduction 1 recurrent dislocator with metal liner dissociation – 3 (2.2%) Loose Cups

19. Results Other Surgical Complication – 5 (3.7%) Deep infections (no dislocation) – 1 Superficial infection – 1 Fascial Dehiscence 1 Death – unrelated Other Complications – 7 Hip Pain (Groin, Iliopsoas, thigh) – 1 Superficial wound infection – 1 Heterotopic Ossification – 1 Sciatic nerve palsy following revision-resolving

20. Results Post op instability by procedure type – 11/93 (12%) Acetabular Revision – 2/20 (10%) Both Component – 1/3 (33%) Liner Revision only

21. Results Dislocation Rate in pts revised for instability – 52 with hx of instability – 7/52 (13%) Recurrent dislocations 39 Patients with instability – 5/39 (13%) Recurrent dislocation 13 Constrained Liners revised to MDM – 2 Recurrent dislocations

22. Conclusion 18% Reoperation rate for any reason 13% Redislocation after instability 10% Dislocation after revision for any reason Pt dislocation rate after revision higher than other published reports Pt often required open reduction after dislocation Closely monitor the long term outcomes of these devices

23. THANK YOU