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

Section 27: Implant Devices and Materials

27-1

27-2 From: Ploeg

27-3 From: Ploeg

27-4 From: Ploeg

What are the goals of TJR? What are the goals of TJR?

• Improve quality of life

Improve quality of life

• Reduce pain

R t f ti

• Restore function

– Movement – Strength

• Last throughout life

g

27-5 From: Ploeg

27-6 From: Ploeg

Smith & Nephew orthopaedics hip portfolio

27-7 From: Kelman

Clinical performance

SPECTRON™ stem

100% survival rate of the

SYNERGY™ stem

99 5% Survivorship SPECTRON stem at 12 years 1 97.0% survival rate of 99.5% Survivorship

4

1 The Charnley Versus the Spectron Hip Prosthesis”

97.0% survival rate of SPECTRON stem at 9.6 years 2 99 7% i l t f

1. The Charnley Versus the Spectron Hip Prosthesis , The Journal of Arthroplasty Vol. 14 No. 14 1999, Goran Garellick, et al MD, PhD. 2. “Hip Arthroplasty With a Collared Straight Cobalt- Chrome Femoral Stem Using Second Generation Cementing Technique”, The Journal of Arthroplasty

99.7% survival rate of SPECTRON EF at 7 yrs 3

g q , p y

• Vol. 15 No. 2 2000, Ashay Kale, MD et al.

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 Th L d H lth S i C t M.D., F.R.C.S.; The London Health Sciences Centre 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 i th i conserving than previous primary implant designs

27-9 From: Kelman

™Trademark of Smith & Nephew.

27-10 From: Materials and Textiles

Failure Modes

Proximal Zone Central Zone C t F t

• Bone-cement interface
• Cement Fracture
• Stem Fracture

Distal Zone

• Bone Resorption
• Cement Fracture
• Bone Fracture

27-11 From: Ploeg

27-12 From: Materials and Textiles

27-13 From: Ploeg

How successful are prosthetic j i ? joints?

• Relieve pain

Relieve pain

• Restore function

M t ( 90%) l t f 10

• Most (>90%) last for >10 years

27-14 From: Ploeg

What artificial biomaterials are l d? most commonly used?

• Metals

Metals

– Stainless steel Cobalt chrome – Cobalt chrome – Titanium alloy

C i l i id

• Ceramics – aluminum oxide
• Polymers

– Bone cement (PMMA) – UHMWPE (polyethylene)

27-15 From: Ploeg

27-16 From: Ploeg

27-17 From: Ploeg

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

27-18 From: Ploeg

p

27-19 From: Ploeg

What are key design criteria for ifi i l bi i l ? artificial biomaterials?

• Restore mechanical function

Restore mechanical function

• Biocompatibility

Ch i ll St bl

• Chemically Stable

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 W – Wear – 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

27-22 From: Ploeg

Not mutagenic, No immunogenic response

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 Li id b ti ( l ) i t – Lipid absorption (polymers) causing property 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

27-24 From: Ploeg

biocompatibility doesn t fix things