DESIGN OF DURABLE IMPLANT FOR TOTAL HIP ATHROPLASTY

Azeez Akeem Abiodun

Akpan Udom Mark

Cooper Lackay

Igwebuike Chidebere. Millicent

Wehleekema Siaplay

Biomaterial

April 2016

OUTLINE

• Introduction• Introduction: Total Hip Replacement• Anatomy of Hip• Indication of Total Hip Replacement• Reason for Hip replacement• Types of Hip replacement surgery• Comparism of wear rate• Suggested solution• Business plan• Conclusion

INTRODUCTION

• In 1960, Late Sir John Charnley has done pioneer work in all aspect of THA, including the concept of low frictional torque arthroplasty, surgical alteration of hip biomechanics, lubrication, materials, design and clear air operating room environment [1].

en.wikipedia.org/wiki/John_Charnley 3

INTRODUCTION :TOTAL HIP REPLACEMENT• Total hip arthroplasty is an

operative procedure in which the diseased and destroyed hip joint is resected and replaced with a new bearing surface [2].

• Patients with arthritis can now look to THA with the object of maintaining stability, while relieving pain, increasing mobility and correcting deformity.

• MOST SIGNIFICANT BREAK THROUGH OF THE 20Th CENTURY

http://www.healthcentral.com/ 4

ANATOMY OF HIP JOINT

• The hip is one of the body's largest weight-bearing joints.

• Consists of two main parts: • a ball (femoral head) that fits into a rounded socket

(acetabulum) in your pelvis.• Ligaments connect the ball to the socket and provide

stability to the joint• The bone surfaces of your ball and socket have a

smooth durable cover of articular cartilage that cushions the ends of the bones and enables them to move easily.

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INDICATIONS FOR THA :• The primary indication for THA is incapacitating PAIN. Pain in

the hip in the presence of destructive process as evidenced by X-ray changes is an indication.

• THA is an option for nearly all patients with diseases of the hip that cause chronic discomfort and significant functional impairment.

• Patients with limitation of movement, leg length inequality and limp but with little or no pain are not the candidates for THR.

Note: All options of treatment must have been explored before considering THA [3].

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REASONS FOR HIP REPLACEMENT

Most common reasons for total hip replacement:• Osteoarthritis 60 %• Rheumatoid arthritis 7 %• Fractures/dislocations 11 %• Aseptic bone necrosis 7 %• Revision 6 %• Other 9% [4]

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HIP REPLACEMENT COMPONENTS

Acetabular component - consists of two components• Cup - usually made of titanium• Liner - can be plastic, metal or

ceramic

• Femoral components Head Neck stem 8

CONVENTIONAL BEARINGS • Osteolysis secondary to polytetrafluroethylene ( Teflon)

particulate debris has emerged as the most notable factor endangering the long-term survivorship of total hip replacements.

• alternative bearings have been advocated to diminish this problem

• These are- -Metal-on-Polyethylene -Ceramic-on-Polyethylene -metal-on-metal -ceramic-on-ceramic [5]

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METAL ON POLYETHYLENE

• This consist of basically three parts: • an ultra-high molecular weight polyethylene

cup that replaces the hip socket,• a metal ball to replace the femoral head and • a metal stem that is inserted into the shaft of

femur to add stability to the prosthesis.

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CERAMIC-ON-POLYETHYLENEThis consist of basically three parts: • an ultra-high molecular weight polyethylene cup

that replaces the hip socket,• a ceramic ball to replace the femoral head and • a metal stem that is inserted into the shaft of femur

to add stability to the prosthesis.

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METAL-ON-METAL BEARINGS • Metal-on-metal implants seem to be tolerant of high

impact loading, and mechanical failure has not been reported.

• wear rates less than 10 mm/y for modern metal-on-metal articulations

• But there remains major concern regarding the production of cobalt and chromium metallic debris, and its elimination from the body.

• metal-on-metal (MOM) bearings have a ‘suction-fit’ less chance of dislocation

(J Bone Joint Surg [Br] 2003;85-B:650-4)12

CERAMIC-ON-CERAMIC BEARINGS

• Alumina ceramic has many properties that make it desirable as a bearing surface in hip arthroplasty

• high density- surface finish smoother than metal implants• The hydrophilic nature- ceramic promotes lubrication• Ceramic is harder than metal and more resistant to scratching from

third-body wear particles.• The linear wear rate of alumina-on-alumina has been shown to be

4000 times less than cobalt-chrome alloy–on–polyethylene.• Ceramic-on-ceramic arthroplasties may be more sensitive to

implant malposition than other bearings. (J Bone Joint Surg [Br] 2003;85-B:650-4

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SURGICAL OPERATION FOR THR

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COMPARISM OF WEAR RATE OF DIFFERENT COMBINATIONS OF THR

15(http://exactech.co.jp/uk/products/hip)

LATEST INNOVATIONS IN DESIGNING THA

• Ceramic-on-UHMWPE• Ceramic-on-HXLPE

http://quotesgram.com/hip-replacement-quotes 16

LATEST INNOVATIONS IN DESIGNING OF FEMORAL HEAD

17Bernard M et al, 2001

REINFORCING SYSTEMS

The main reinforcing materials that are biocompatible are • Carbon fiber• Glass fibers• Polymer fiber• Ceramics fibers

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PROPOSED SOLUTIONWe propose that using Alumina Matrix Composite (AMC) will address the brittle nature of alumina made femoral head.• Calcium phosphate belong to group of bioactive synthetic material Hydroxyapatite (Non-resorbable) Tricalcium phosphate (resorbable) • Using calcium phosphate as second phase will toughen the femoral

head by arresting crack through crack bridging.• Research needs to be carried out to determine the best volume

fraction of hydroxyapatite particles that we provide the desired fracture toughness.

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MECHANICAL PROPERTIES OF AMC

Source: Gulio et al, 2013Source: Jabr.S et al, 2013

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RULE OF MIXTURE FOR COMPOSITE

By varying the volume fractions of the matrix and particles, we can determine the best Young’s modulus of the composite that will resist crack propagation.

http://slideplayer.com/slide/3091954/ 21

RULE OF MIXTURE CONT’D

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BUSINESS PLANFrom data we got from CIA world fact book (www.cia.gov), Nigeria demographics• 15-24 years: 19.3% (male 17,486,117/female 16,732,533)• 25-54 years: 30.5% (male 27,67,644/female 3,571,301)• 65 years and over: 3.1% (male 2,621,845/female 2,861,826) (2014 est.)

Reason for THA :• Osteoarthritis 60 %• Fractures/dislocations 11 %

Average cost of Total Hip Arthroplasty implant surgery:

Ceramic-on-ceramic $7,500

Metal-on-metal $5,500

With our proposed material, we will reduce the number times of revision and as well cost

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CONCLUSION• We did literature review on various combinations of THA implant• Our research shows that ceramic-on-ceramic THA has the lowest wear rate and

therefore has the potential of having greatest survivorship of all the combinations.

• Disadvantages are:BrittlenessHigh cost

In lieu of this, we propose

Ceramic-on-HXLPE (for efficiency and to reduce cost )

NanoAlumina matrix composite (AMC) to drastically reduce crack propagation and toughening of the femoral head.

Thereby reducing cost and number of revision surgery.http://www.jortho.org/ 24

REFERENCES1. en.wikipedia.org/wiki/John_Charnley 2. http://www.uptodate.com/contents/total-hip-replacement-arthroplasty-beyond-the-basics retrieved on 10th, April 2016.3.http://www.niams.nih.gov/Health_Info/Hip_Replacement/hip_replacement_ff.asp retrieved on 10th , April 2016

4. Monti khato et al:An analysis of the risk of hip dislocation with contemporary total joint registry.5. Brummitt K, Hardaker CS, McCullagh PJ, Drabu KJ, Smith RA. Effect of counterface material on the characteristics of retrieved titanium alloy total hip replacements. J Eng Med 1996;210(3): 191–56.Jabr.S, A. Madfa et al: Review article on Application of calcium phosphate materials in dentistry. 25