screw fixation for ACL reconstruction

1. Interference screw in ACL
reconstruction
WHAT ARE THE REQUIRED PROPERTIES FOR GOOD SCREW AND WHICH
MATERIAL IS THE BEST FOR THAT USE

3. ACL anatomy and rupture
University of Maryland Medical Center – http://umm.edu/health/medical/ency/presentations/anterior-cruciate-ligament-repair-series

4. Reconstruction
University of Maryland Medical Center – http://umm.edu/health/medical/ency/presentations/anterior-cruciate-ligament-repair-series

5. Degradable Interference Screw
NEC-PLUS® Interference Screw
Poly (L/DL Lactide) 70-30 absorbable screw

6. Screw location
M. Chizari, M. Alrashidi, K. Alrashdan, and I. Yildiz, “Mechanical Aspects of an Interference Screw Placement in ACL Reconstruction,” pp. 18–20

7. Material requirement
Mech
prop
Bio
comp
Bio
deg
PLA
M. Chizari, M. Alrashidi, K. Alrashdan, and I. Yildiz, “Mechanical Aspects of an Interference Screw Placement in ACL Reconstruction,” pp. 18–20

8. Mechanical prop.
K. F. Farraro, K. E. Kim, S. L. Y. Woo, J. R. Flowers, and M. B. McCullough, “Revolutionizing orthopaedic biomaterials: The potential of biodegradable and bioresorbable
magnesium-based materials for functional tissue engineering,” J. Biomech., vol. 47, no. 9, pp. 1979–1986, 2014.
892919
70100
0
100
200
300
400
500
600
700
800
900
1000
Yield Strength [Mpa]
AISI 316L Titanium PLA bone
210
106
414
0
50
100
150
200
250
Young Modulus [Gpa]
AISI 316L Titanium PLA bone
17
16
7
3
0
2
4
6
8
10
12
14
16
18
Elongation [%]
AISI 316L Titanium PLA bone

9. Parameters affecting Biocompatibility
Y. Ramot, M. H. Zada, A. J. Domb, and A. Nyska, “Biocompatibility and safety of PLA and its copolymers,” Adv. Drug Deliv. Rev., vol. 107, pp. 153–162, 2015.
ImplantHost
Shape and sizeType of tissue
CompositionLocation in the body
Roughness of surfaceSurrounding environment
MorphologyGenetics
Porosity
Sterility
Duration of contact

10. Parameters affecting BioDegradation
Y. Ramot, M. H. Zada, A. J. Domb, and A. Nyska, “Biocompatibility and safety of PLA and its copolymers,” Adv. Drug Deliv. Rev., vol. 107, pp. 153–162, 2015.
ImplantHost
Shape and sizepH
Spatial structureTemperature
Hydro-philicity/phobicity
Surface morphology
Porosity
Sterility
Duration of contact

11. Why Biodegradation ?
Problems of the
Traditional screw
potentially
need to be
removed
hinder
MRI/CT
Rupture of
implant
Y. Arama, L. J. Salmon, K. Sri-Ram, J. Linklater, J. P. Roe, and L. A. Pinczewski, “Bioabsorbable Versus Titanium Screws in Anterior Cruciate Ligament Reconstruction
Using Hamstring Autograft: A Prospective, Blinded, Randomized Controlled Trial With 5-Year Follow-up.,” Am. J. Sports Med., vol. 43, no. 8, pp. 1893–1901, 2015.

12. Stereoisomerism of PLA
isomerMonomerRepetitive unit
L
D
K. Masutani and Y. Kimura, PLA Synthesis and Polymerization. 2014.

13. Crystallinity
Y. Onuma and P. W. Serruys, “Bioresorbable scaffold: The advent of a new era in percutaneous coronary and
peripheral revascularization?,” Circulation, vol. 123, no. 7, pp. 779–797, 2011.

14. L-isomer
High crystallinity
Less amorphous
region
Reduce
Hydration
-CH3
Hydrophobicity
Reduce
degradation rate
tensile &
yield
strength
Reduce
elongation
S. Farah, D. G. Anderson, and R. Langer, “Physical and mechanical properties of PLA, and their functions in
widespread applications - A comprehensive review,” Adv. Drug Deliv. Rev., vol. 107, pp. 367–392, 2016.
R. M. Rasal, A. V. Janorkar, and D. E. Hirt, “Poly(lactic acid) modifications,” Prog.
Polym. Sci., vol. 35, no. 3, pp. 338–356, 2010.
Reduce FBR

15. Degradation method
Y. Onuma and P. W. Serruys, “Bioresorbable scaffold: The advent of a new era in percutaneous coronary and peripheral revascularization?,”
Circulation, vol. 123, no. 7, pp. 779–797, 2011.
Hydration
Ester-
Hydrolysis
Mass loss Dissolution

16. Y. Onuma and P. W. Serruys, “Bioresorbable scaffold: The advent of a new era in percutaneous coronary and peripheral
revascularization?,” Circulation, vol. 123, no. 7, pp. 779–797, 2011.

17. PLA limitations
K. F. Farraro, K. E. Kim, S. L. Y. Woo, J. R. Flowers, and M. B. McCullough, “Revolutionizing orthopaedic biomaterials: The potential of biodegradable
and bioresorbable magnesium-based materials for functional tissue engineering,” J. Biomech., vol. 47, no. 9, pp. 1979–1986, 2014.
1Young’s modulus similar to the bone
2Degradation
3Allow bone regeneration (?)
4Properties control (?)
5Allow MRI/CT
1Break during surgery
2Slow degradation rate
3Bad bone regeneration
4Inaccurate control

18. Resent studies

19. Solution for bone regeneration
3D
print
Stem
cell
HA
coat
Hydro
gel
Bone
hilling
K. F. Farraro, K. E. Kim, S. L. Y. Woo, J. R. Flowers, and M. B. McCullough, “Revolutionizing orthopaedic biomaterials: The potential of
biodegradable and bioresorbable magnesium-based materials for functional tissue engineering,” J. Biomech., vol. 47, no. 9, pp. 1979–1986,

20. Mg alloys - AZ31 | MgZnCa
K. F. Farraro, K. E. Kim, S. L. Y. Woo, J. R. Flowers, and M. B. McCullough, “Revolutionizing orthopaedic biomaterials: The potential of biodegradable
and bioresorbable magnesium-based materials for functional tissue engineering,” J. Biomech., vol. 47, no. 9, pp. 1979–1986, 2014.
1.Young modulus similar to the bone = 40-45 [GPa]
2.Tensile strength greater than polymer
3.Good elongation = 16%
4.Allow MRI
5.controlled degradation time

21. Summery
1. ACL reconstruction is very common, hence it is extensively
studied.
2. What makes successful screw is: properties similarity to the
human bone, biocompatibility, accelerate bone regeneration.
3. Despite its limitations, PLA demonstrates few important benefits
that justifies further research and development.

22. My Opinion
Despite recent breakthroughs in printed metals, I think that PLA still
has major advantage over metals which is the friendly, easy and
cheap printability using FDM printers.
This will be useful especially when availability is an important factor,
for example, in orthopedic departments.

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ACL Reconstruction Team Members :,” 2005.
[2] M. Chizari, M. Alrashidi, K. Alrashdan, and I. Yildiz, “Mechanical Aspects of an Interference
Screw Placement in ACL Reconstruction,” pp. 18–20.
[3] M. Chizari, B. Wang, M. Snow, and M. Barrett, “Experimental and numerical analysis of
screw fixation in anterior cruciate ligament reconstruction,” AIP Conf. Proc., vol. 1045, pp. 61–
70, 2008.
[4] N. Caplan and D. F. Kader, “Biomechanical analysis of human ligament grafts used in knee-
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[5] S. O. Adeosun, G. I. Lawal, and O. P. Gbenebor, “Characteristics of Biodegradable
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[7] S. Farah, D. G. Anderson, and R. Langer, “Physical and mechanical properties of PLA, and
their functions in widespread applications - A comprehensive review,” Adv. Drug Deliv. Rev.,
vol. 107, pp. 367–392, 2016.
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[9] Y. Ramot, M. H. Zada, A. J. Domb, and A. Nyska, “Biocompatibility and safety of PLA and its
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26. [10]Y. Arama, L. J. Salmon, K. Sri-Ram, J. Linklater, J. P. Roe, and L. A. Pinczewski, “Bioabsorbable
Versus Titanium Screws in Anterior Cruciate Ligament Reconstruction Using Hamstring
Autograft: A Prospective, Blinded, Randomized Controlled Trial With 5-Year Follow-up.,” Am. J.
Sports Med., vol. 43, no. 8, pp. 1893–1901, 2015.
[11]D. N. M. Caborn, W. P. Urban, D. L. Johnson, J. Nyland, and D. Pienkowski, “Biomechanical
comparison between BioScrew and titanium alloy interference screws for bone-patellar tendon-
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[13]K. Masutani and Y. Kimura, PLA Synthesis and Polymerization. 2014.
[14]G. E. Luckachan and C. K. S. Pillai, “Biodegradable Polymers- A Review on Recent Trends and
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27. [15]R. M. Rasal, A. V. Janorkar, and D. E. Hirt, “Poly(lactic acid) modifications,” Prog. Polym. Sci.,
vol. 35, no. 3, pp. 338–356, 2010.
[16]Y. Onuma and P. W. Serruys, “Bioresorbable scaffold: The advent of a new era in
percutaneous coronary and peripheral revascularization?,” Circulation, vol. 123, no. 7, pp. 779–
797, 2011.
[17]A. Liu et al., “3D Printing Surgical Implants at the clinic: A Experimental Study on Anterior
Cruciate Ligament Reconstruction.,” Sci. Rep., vol. 6, no. October 2015, p. 21704, 2016.
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orthopaedic biomaterials: The potential of biodegradable and bioresorbable magnesium-based
materials for functional tissue engineering,” J. Biomech., vol. 47, no. 9, pp. 1979–1986, 2014.
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