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‘The low-down’

• The replacement- ‘The enemy’• The problem with Hip prosthesis• 3 Possible ways to improve the Hip prosthesis• Summary

Stem Cells

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The replacement

Stem cells therapy used in a patient.

Spire hospital, Southampton.

• The patient’s own bone marrow to harvest stem cells

• Stem cells grown in lab and injected into Hip with platelet rich plasma

• Problems: Expensive, storage, availability and regulatory issues.

Problems with Hip Prosthesis

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Mechanically-assisted crevice corrosionMicro motion + crevice

corrosion between head and stem

High Wear rates

Usually between Head and Cup

Capsule formation

Host reaction to bacterial infection of implant.

Infection liability

Can be infected very easily during surgery.

Hard to solve all at once

MPC Polymer

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2-methacryloyloxyethyl phosphorylchlorine (MPC).

MPC Polymer

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Solution 1

Fig1. Long‐term testing of the artificial

hip joint bearing surface grafted with MPC

About MPC

• Resemble phospholipid bilayer through polar groups• Can radically decrease wear between head and cup• Can prevent bacterial attachment due to

‘superhydrophilicity’/ inhibiton of cell adhesion• Does not cause inflammatory response when in

contact with macrophages

“Discovered in 1978 but could only produce 1mg per year!”

Fig1,2. Moro T, Takatori Y, Kyomoto M, Ishihara K, Hashimoto M, Ito H et al. Long-term hip simulator testing of the artificial hip joint bearing surface grafted with biocompatible phospholipid polymer. J Orthop Res. 2013;32(3):369-376.

Fig2. Showing MPC liner structure and

acetabular cup with MPC liner

PEEK FIBRESSelf Reinforced CompositeSO

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PEEK FIBRES

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Solution 2

Fig3. Difference in current as load increases,

in hip implants with/without PEEK Fibres

About PEEK Fibers

• Placed in between the taper region of the implant• Usually two fibres, which spread out to cover the

neck of the implant• Forms a tighter connection between head and neck• Results in soft, non-conducting layer, preventing the

loss of the oxide film.

“Compulsory with Metal implants in the US since 2014!”

 

Fig3. Google Books, (2015). Patent US20140197571 - Prevention of fretting crevice corrosion of modular taper interfaces in orthopedic implants. [online] Available at: http://www.google.com/patents/US20140197571 [Accessed 15 Feb. 2015].

CAPE LOADED PMMABone CementSO

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CAPE LOADED PMMA

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Solution 3

Fig4. Showing CAPE and GM

dispersion within a PMMA network

About CAPE loaded PMMA

• Active component of bee propolis ( used to fill holes in bee hives)

• Has antimicrobial, anti-inflammatory, antioxidant and anti-cancer effects

• Better compressive strength than GM-PMMA. Similar to native PMMA

• Higher packing density caused by reinforced chemical bonding between the PMMA and CAPE

• More controlled and sustained microbial release

Fig3: Lee H, Chang J. Antimicrobial spine-bone cement with caffeic acid phenethyl ester for controlled release formulation and in vivo biological assessments. Med Chem Commun. 2015;6(2):327-333.

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The Stem cell revolution is taking over from the Hip prosthesis

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There are numerous problems with the Hip prosthesis

MACC, Wear, Capsulation and infection are the main ones

MPC can decrease wear rate significantly

PEEK can reduce MACC between the head and stem of a metal implant

CAPE loaded PMMA is a good replacement to GM-PMMA.

KEY TAKEAWAYSThe Important Stuff

That’s all. Thank you! Any Questions?

References

• Spirehealthcare.com. Stem cell technique prevents hip replacements [Internet]. 2015 [cited 26 February

2015]. Available from:

http://www.spirehealthcare.com/southampton/news/stem-cells-technique-to-prevent-hip-replacements/

• Plancher Orthopedics. Are Stem Cells the Future of Hip Replacement? - Plancher Orthopedics [Internet]. 2014

[cited 25 February 2015]. Available from: http://plancherortho.com/stem-cells-future-hip-replacement/

• J Centeno C. Efficacy and Safety of Bone Marrow Concentrate for Osteoarthritis of the Hip; Treatment Registry

Results for 196 Patients. Journal of Stem Cell Research & Therapy. 2014;04(10). • Moro T, Kawaguchi H, Ishihara K, Kyomoto M, Karita T, Ito H et al. Wear resistance of artificial hip joints with

poly(2-methacryloyloxyethyl phosphorylcholine) grafted polyethylene: Comparisons with the effect of polyethylene cross-linking and ceramic femoral heads. Biomaterials. 2009;30(16):2995-3001.

• Moro T, Takatori Y, Kyomoto M, Ishihara K, Hashimoto M, Ito H et al. Long-term hip simulator testing of the artificial hip joint bearing surface grafted with biocompatible phospholipid polymer. J Orthop Res. 2013;32(3):369-376.

• Google Books, (2015). Patent US20140197571 - Prevention of fretting crevice corrosion of modular taper

interfaces in orthopedic implants. [online] Available at: http://www.google.com/patents/US20140197571

[Accessed 15 Feb. 2015].

• Nakahara I, Takao M, Bandoh S, Sugano N. Fixation strength of taper connection at head–neck junction in

retrieved carbon fiber-reinforced PEEK hip stems. Journal of Artificial Organs. 2014;17(4):358-363.

• Rsc.org. From beehive to bone cement | Chemistry World [Internet]. 2015 [cited 25 February 2015]. Available from: http://www.rsc.org/chemistryworld/2014/11/bone-cement

• Lee H, Chang J. Antimicrobial spine-bone cement with caffeic acid phenethyl ester for controlled release formulation and in vivo biological assessments. Med Chem Commun. 2015;6(2):327-333.