Randomised study comparing Cr Co whole blood ions

Randomised study comparing Cr. Co whole blood ions in Mo. M 28 mm THA and Mo. M SRA Vendittoli PA, Lavigne M, Mottard S, Roy A VS Sophie Mottard M. D.

Blood ions in metal-on-metal bearing surfaces Early metal-on-metal bearings 1938 P. Wiles 1965 1966 stainless steel G. K. Mc. Kee M. E. Müller prosthesis Co. Cr prosthesis Sophie Mottard M. D.

Blood ions in metal-on-metal bearing surfaces Key Factors hard on hard success. . . Cast alloy • Optimal materials • Surface roughness • Well ajusted clearance • Precise manufacturing • Design Sophie Mottard M. D. Wrought alloy

Blood ions in metal-on-metal bearing surfaces Possible Advantages Mo. M Bearing Surfaces • Improved durability; • Wear-resistant components; • Absence of polyethylene particules; • No secondary periprosthetic osteolysis. Radiograph of Müller MOM at 33 -year follow-up Sophie Mottard M. D.

Blood ions in metal-on-metal bearing surfaces Metal ions productions Under perfect conditions; • Wear • Corrosion • Gradual elimination of metal ions by the kidneys • Osteolysis: rare or should not occur Concerns persist - Tissue necrosis - Cancer risk - Allergies / hypersensitivity Sophie Mottard M. D.

Blood ions in metal-on-metal bearing surfaces Modern Mo. M implants Serum levels with 28 mm Co. Cr implants 1988 introduction of Metasul® Metal-on-Metal W. Brodner, JBJS 2003 Sophie Mottard M. D.

Blood ions in metal-on-metal bearing surfaces Clinical experience with Mo. M “Larger Mc. Kee-Farrar heads showed less volumetric wear than small diameter heads” “In Vivo wear of metal on metal prosthesis during two decades of use” Mc. Kellop, CORR Aug 1996 Sophie Mottard M. D.

Blood ions in metal-on-metal bearing surfaces Analysis of fluid film lubrication in artificial hip joint replacements PROC INSTN MECH ENGRS 1997; VOL 211 PART 2 : 247 -256 ( JIN , DOWSON, FISHER) “LARGER RADIUS HEAD AT SAME RADIAL CLEARANCE LEADS TO AN INCREASE IN FLUID FILM THICKNESS” JIN, DOWSON, FISHER Sophie Mottard M. D.

Blood ions in metal-on-metal bearing surfaces Randomised study comparing whole blood metal ions in Mo. M 28 mm THA and Mo. M SRA Sophie Mottard M. D.

Blood ions in metal-on-metal bearing surfaces Study hypothesis • Larger head sizes of Mom SRA would produce more metallic ions in comparison to 28 mm Mo. M THA. Main objective — Compare metal chrome, cobalt and titanium blood ions between Mo. M 28 mm THA and Mo. M SRA. Specific objectives — — — Corelate morphological or biomedical; factors (age, sex, weight, activity level) and metal ions levels; Determine wear in period for the 2 groups; Steady state whole blood metal ion level. Sophie Mottard M. D.

Blood ions in metal-on-metal bearing surfaces Study population HMR patient 18 -65 years old waiting for THA by one of the hip surgeons and candidate for a THA or a SRA Exclusion criterias — — — — — One-stage bilateral THA; Charnley class C patients; Deep joint infection; Drugs, alcool abuse, psychiatric illness; Pregnancy; Hip arthrodesis; Neuromuscular disorder; Renal insufficiency; Known or suspected metal allergy; Known or suspected osteopenia or osteoporosis of the hip. Sophie Mottard M. D.

Blood ions in metal-on-metal bearing surfaces Implants: SRA DUROM, Zimmer Warsaw Head Wrought Co-28 Cr-6 Mo, 0. 2% C Cemented 2 mm increments (head and cup ) Cup Wrought Co-28 Cr-6 Mo, 0. 2% C Wall thickness = 4 mm Non modular Ti plasma spray for ingrowth Sophie Mottard M. D.

Blood ions in metal-on-metal bearing surfaces Implants : THA CLS stem (Spotorno), Zimmer Warsaw • Wrought Titanium; • Uncemented (grit blasted surface). Allofit cup, Zimmer Warsaw • Macro textured wrought titanium; • 2. 9 mm thickness; • Modular with poly sandwich Cr. Co metasul insert. Sophie Mottard M. D.

Blood ions in metal-on-metal bearing surfaces Blood collection • Whole Blood samples — Pre-op — 3 months — 6 months — 1 year — 2 years post-op 1. 2. 5 ml Collect Analysis to H 600 PP (conserve in the freezer [-20ºC]) be done Teklab Stir well 3. 10 ml Conserve TKA H 600 PP Stir well Sophie Mottard M. D. Discard In case of lost or need for a second analysis 20° C

Blood ions in metal-on-metal bearing surfaces Ion Analysis Finnaigan MAT Element 1 High Resolution Sector Field Inductively Coupled Plasma Mass Spectrometer ( HR-SF-ICPMS). Blood samples — — Digest blood with concentrated Nitric Acid; Add concentrated Hydrogen Peroxide to further digest lipids; Dilution with water and internal standard; Introduced into the spectrometer; Practical Detection Limits — Titanium - 0. 1 ug/L — Chromium - 0. 1 ug/L — Cobalt - 0. 01 ug/L London, Ontario Lab Sophie Mottard M. D.

Blood ions in metal-on-metal bearing surfaces Power Analysis Chromium • Minimal difference to be detected= 1 ug/L • Standard deviation in resurfacing= 1. 03 * • Alpha error of 5% (bilateral) • Power 85% • N=20 per group • Estimated loss to follow-up 15% • Required subjects N= 50 patients. (25 per group) *Jacobs JJ, Clin Orthop 1996 Sophie Mottard M. D.

Blood ions in metal-on-metal bearing surfaces Study population N=85 THA Sexe Women 18 Men 24 52 Age (years) SRA 12 31 48 Surgery 42 43 Head size (mm) BMI Kg/m 2 (mean) 28 (All) 28, 67 49 (avg) 26, 86 Sophie Mottard M. D.

Blood ions in metal-on-metal bearing surfaces Factors taken under consideration • • • Sophie Mottard M. D. Sex; Smoking; Comorbidities; Blood sampling in the two weeks prior; Work exposure to metal; Work exposure radioactive substances; Other metallic implants; Medication; Naturals products; Activity level UCLA score; Cup inclinaison.

Blood ions in metal-on-metal bearing surfaces Results Mean Chrome blood levels THA vs SRA Blood chrome (µg/L) 1, 69 1, 10 1, 60 1, 76 1, 65 1, 06 32 37 Sophie Mottard M. D. 2, 35 2, 23 29 32 23 29 10 13

Blood ions in metal-on-metal bearing surfaces Results Median chrome blood levels THA vs SRA Blood chrome 2, 00 (µg/L) 1, 50 0, 90 1, 45 1, 65 0, 85 32 37 Sophie Mottard M. D. 1, 90 29 32 23 29 10 13

Blood ions in metal-on-metal bearing surfaces Mean chrome, 1 standard deviation Sophie Mottard M. D.

Blood ions in metal-on-metal bearing surfaces Results Mean Cobalt blood levels THA vs SRA Blood cobalt 1, 00 (µg/L) 0, 76 0, 15 0, 80 0, 78 0, 77 0, 12 32 37 Sophie Mottard M. D. 0, 81 29 32 23 29 10 13

Blood ions in metal-on-metal bearing surfaces Results Median cobalt blood levels THA vs SRA 0, 96 Blood cobalt 0, 78 (µg/L) 0, 74 0, 73 0, 54 0, 12 0, 11 32 37 Sophie Mottard M. D. 29 32 23 29 10 13

Blood ions in metal-on-metal bearing surfaces Mean cobalt, 1 standard deviation Sophie Mottard M. D.

Blood ions in metal-on-metal bearing surfaces Results • Sex; • Smoking; • Comorbidities; • Blood sampling in the two weeks prior; • Work exposure to metal; • Work exposure radioactive substances; • Other metallic implants; • Medication; • Naturals products; • Activity level UCLA score; • Cup inclinaison. Sophie Mottard M. D. No statistically significant correlation

Blood ions in metal-on-metal bearing surfaces Discussion THA 28 mm Our Results, Metasul (1 y) Cr ( g/l) 1, 65 Brodner, Metasul (5 y) Jacobs, Mckee-Farrar (20 -27 y) Co ( g/l) 0, 78 0. 70 1, 23 Mc. Donald, Biomet M 2 a (2 - 3. 6 y) low/high carbon 0, 90 3. 74 SRA Our Results, Durom (1 y) 2, 35 0, 77 Jacobs, various SRA 3. 86 2, 80 Sophie Mottard M. D.

Blood ions in metal-on-metal bearing surfaces Discussion • Short wear in period; • Stable ion concentration levels by 6 months; • Both implants with the same Mo. M technology; — — Metallurgy Wrought Cr. Co High carbon content (0. 2%) Tribology — Clearance — Sphericity — Surface roughness Sophie Mottard M. D. Metasul® Metal-on-Metal Over 18 years of clinical experience and 250, 000 implantations worldwide.

Blood ions in metal-on-metal bearing surfaces From the Theory (Jin and Fisher) Small heads Large heads head size Sophie Mottard M. D. } film fluid thickness Wear

Blood ions in metal-on-metal bearing surfaces Discussion Similar Cr. Co levels ug/L Cr 1. 65 2, 35 Co 0, 78 0, 77 2 Hypothesis: • Corrosion Larger exposed surface increases ions in SRA • In vivo = various lubrification modes — Fluid film — Bondary Both factor together might create similar amount ? Sophie Mottard M. D.

Blood ions in metal-on-metal bearing surfaces Conclusions • Large and 28 mm diameters Metasul articulations produce similar metal ions during the first year of implantation. • Cr. Co metal ions levels obtained could be consider safe from historical results obtained with similar levels. Sophie Mottard M. D.

Blood ions in metal-on-metal bearing surfaces Acknowledgments • Daniel Lusignan, Research nurse • Stéphanie Lapointe, Research assistant Zimmer, Warsaw for financial support Sophie Mottard M. D.