Section 27: Implant Devices and Materials 27-1 From: Ploeg 27-2 - PDF document

Section 27: Implant Devices and Materials 27-1

From: Ploeg 27-2

From: Ploeg 27-3

From: Ploeg 27-4

What are the goals of TJR? What are the goals of TJR? • Improve quality of life Improve quality of life • Reduce pain • Restore function R t f ti – Movement – Strength • Last throughout life g 27-5 From: Ploeg

From: Ploeg 27-6

Smith & Nephew orthopaedics hip portfolio 27-7 From: Kelman

Clinical performance SPECTRON™ stem SYNERGY™ stem 100% survival rate of the 99.5% Survivorship 99 5% Survivorship SPECTRON stem at 12 4 years 1 97.0% survival rate of 97.0% survival rate of 1. 1 The Charnley Versus the Spectron Hip Prosthesis” The Charnley Versus the Spectron Hip Prosthesis , The Journal of Arthroplasty Vol. 14 No. 14 1999, SPECTRON stem at 9.6 Goran Garellick, et al MD, PhD. years 2 2. “Hip Arthroplasty With a Collared Straight Cobalt- Chrome Femoral Stem Using Second Generation Cementing Technique”, The Journal of Arthroplasty g q , p y 99.7% survival rate of 99 7% i l t f Vol. 15 No. 2 2000, Ashay Kale, MD et al. SPECTRON EF at 7 yrs 3 3. Swedish National Hip Registry, 2000 Report, Henrik Malchau, MD, PhD 4. Bourne, Robert, M.D., F.R.C.S.; Rorabeck, Cecil, M.D., F.R.C.S.; The London Health Sciences Centre M D F R C S Th L d H lth S i C t Experience: Synergy Tapered Hip System; International Hip Meeting. Prague, Czech Republic. May 2001 27-8 From: Kelman ™Trademark of Smith & Nephew. Reg. US Pat. & TM Off.

ANTHOLOGY™ Hip System ANTHOLOGY Hip System • Value proposition Value proposition – The ANTHOLOGY™ system provides the surgeon a press provides the surgeon a press- fit implant that is optimum for all femur types – It is designed to be MIS friendly, reduce dislocations, and be more bone and tissue conserving than previous i th i primary implant designs 27-9 From: Kelman ™Trademark of Smith & Nephew.

From: Materials and Textiles 27-10

Failure Modes Proximal Zone Central Zone • Cement Fracture C t F t • Stem Fracture • Bone-cement interface Distal Zone • Cement Fracture • Bone Fracture • Bone Resorption 27-11 From: Ploeg

From: Materials and Textiles 27-12

From: Ploeg 27-13

How successful are prosthetic j i joints? ? • Relieve pain Relieve pain • Restore function • Most (>90%) last for >10 years M t ( 90%) l t f 10 27-14 From: Ploeg

What artificial biomaterials are most commonly used? l d? • Metals Metals – Stainless steel – Cobalt chrome Cobalt chrome – Titanium alloy • Ceramics – aluminum oxide C i l i id • Polymers – Bone cement (PMMA) – UHMWPE (polyethylene) 27-15 From: Ploeg

From: Ploeg 27-16

From: Ploeg 27-17

Polymers Polymers • Bone cement (PMMA) Bone cement (PMMA) – Exothermic – Toxic effects of monomer Toxic effects of monomer – Shrinkage with polymerization – Grout, not adhesive , • UHMWPE (polyethylene) – Lipid absorption p p – Wear particles – Low coefficient of friction and creep resistant p 27-18 From: Ploeg

From: Ploeg 27-19

What are key design criteria for artificial biomaterials? ifi i l bi i l ? • Restore mechanical function Restore mechanical function • Biocompatibility • Chemically Stable Ch i ll St bl 27-20 From: Ploeg

Requirements for Biomaterials Requirements for Biomaterials • Must re-establish mechanical function with Must re establish mechanical function with healing or replacement: – Structural and mechanical criteria Structural and mechanical criteria – Strength – Stiffness Stiffness – Fatigue life – Wear W – Wear debris 27-21 From: Ploeg

Requirements for Biomaterials Requirements for Biomaterials • Must be biocompatible Must be biocompatible – No inflammatory response – Inflammation causes lymphocyte invasion, Inflammation causes lymphocyte invasion vascular occlusion, tissue necrosis, fibrous tissue formation, prosthesis / implant tissue formation, prosthesis / implant loosening – Not carcinogenic g – Not toxic – Not mutagenic, No immunogenic response Not mutagenic, No immunogenic response 27-22 From: Ploeg

Requirements for Biomaterials Requirements for Biomaterials • Must not be adversely affected by Must not be adversely affected by biological environment, i.e. stable – Non-corrosive (metals) to minimize: Non corrosive (metals) to minimize: – Stress corrosion – Galvanic corrosion Galvanic corrosion – Crevice corrosion – Lipid absorption (polymers) causing property Li id b ti ( l ) i t degradation 27-23 From: Ploeg

Requirements for Biomaterials Requirements for Biomaterials • Manufacturing and Use Manufacturing and Use – Machinability • Ductility (plates must be contoured during use) • Ductility (plates must be contoured during use) – Cost and supply – Requisite size (determined by mechanical Requisite size (determined by mechanical properties) versus available space – Sterilizable Sterilizable – Size of material (i.e. wear debris) biocompatibility doesn’t fix things biocompatibility doesn t fix things 27-24 From: Ploeg