ulementar inormationimages.nature.com/.../2017/s41551-017-0080/extref/s41551-017-0080-s1.pdfeluting...

In the format provided by the authors and unedited.

1

A Fully Functional Drug-Eluting Joint Implant

1,2,3 Suhardi VJ, 1,2Bichara DA, Kwok SJJ3,4, Freiberg AA2, Rubash H2, Malchau H2, Yun SH3,4, 1,2Muratoglu OK,1,2Oral E*

1Harris Orthopaedic Laboratory, Massachusetts General Hospital, Boston, MA.

2Department of Orthopaedic Surgery, Harvard Medical School.

3 Department of Medical Engineering and Medical Physics, Massachusetts Institute of Technology.

4Wellmann Center for Photomedicine, Massachusetts General Hospital, Boston, MA

*Corresponding Author: Ebru Oral Address: 55 Fruit Street, GRJ 1206, Boston, MA 02215, USA Phone: Fax: Email: [email protected]

© 2017 Macmillan Publishers Limited, part of Springer Nature. All rights reserved.

SUPPLEMENTARY INFORMATIONVOLUME: 1 | ARTICLE NUMBER: 0080

NATURE BIOMEDICAL ENGINEERING | DOI: 10.1038/s41551-017-0080 | www.nature.com/natbiomedeng 1

http://dx.doi.org/10.1038/s41551-017-0080

2

Table of Content Supplementary Discussion ............................................................................................... 3 Supplementary Figure 1 .................................................................................................... 5 Supplementary Figure 2 .................................................................................................... 5 Supplementary Figure 3 .................................................................................................... 6 Supplementary Figure 4 .................................................................................................... 7 Supplementary Figure 5 .................................................................................................... 8 Supplementary Figure 6 .................................................................................................... 8 Supplementary Figure 7 .................................................................................................... 9 Supplementary Figure 8 .................................................................................................. 10 Supplementary Figure 9 .................................................................................................. 10 Supplementary Figure 10 ................................................................................................ 11 Supplementary Figure 11 ................................................................................................ 12 Supplementary Figure 12 ................................................................................................ 13 Supplementary Figure 13 ................................................................................................ 13 Supplementary Figure 14 ................................................................................................ 14 Supplementary Figure 15 ................................................................................................ 15 Supplementary Figure 16 ................................................................................................ 15 Supplementary Figure 17 ................................................................................................ 16 Supplementary Figure 18 ................................................................................................ 16 Supplementary Figure 19 ................................................................................................ 17 Supplementary Table 1 ................................................................................................... 18 Supplementary Table 2 ................................................................................................... 19 Supplementary Table 3 ................................................................................................... 20 Supplementary Table 4 ................................................................................................... 21



SUPPLEMENTARY INFORMATION

http://dx.doi.org/10.1038/s41551-017-0080

3

Supplementary Discussion 1

Strength and Wear Resistance Requirements of UHMWPE for Load-Bearing Prosthetic Joints

The mechanical and tribological requirements of UHMWPE as load-bearing prosthetic joints are dictated by the biomechanics of each joint. In the hip, UHMWPE is used as acetabular cup with maximum contact stress of 14-16 MPa.1 In the knee, UHMWPE is used as tibial insert with higher maximum contact stress of 16-28 MPa.2,3 In addition to strength requirements to resist deformation and fracture against contact stresses, wear resistance is required against multi-directional articulating motion between UHMWPE and its counter surface in the joints. Multidirectional, but not unidirectional motion has been shown to induce transverse rupture of elongated UHMWPE fibrils, resulting in the wear of UHMWPE bearing surfaces.4 Wear resistance is an essential requirement because wear particles have long been associated with peri-prosthetic osteolysis, which leads to loosening and failure of the implants.

Radiation cross-linking is the universally accepted method of increasing wear resistance of UHMWPE bearing surfaces. Increasing radiation dose is used to increase wear resistance but also decreases mechanical strength and toughness. The lowest radiation dose used is for ‘conventional’ UHMWPE, which receives radiation only for the purpose of sterilization is in the (0-40 kGy) range. There are number of highly cross-linked UHMWPEs (>40 kGy irradiated), which have been developed for higher wear resistance.5 In total hips, where wear resistance requirements are higher (due to higher frequency of multidirectional motion), about 95% of all joints comprise a highly cross-linked UHMWPE bearing surface6 in contrast to about 50% of total knee replacements because wear resistance requirements are less stringent (due to higher frequency of unidirectional motion).

Tensile mechanical testing, impact testing and in vitro pin-on-disc wear testing or simulator testing are the most common methods of evaluating UHMWPE formulations in vitro.5 Conventional UHMWPE has an ultimate tensile strength (UTS) of 47-50 MPa7, an elongation to break (EAB) of 373-421 %7, impact strength (IS) of 90-96 kJ/mm2,8 and wear rate of 6-11 mg/million cycle.9 Highly-crosslinked UHMWPEs have UTS of 34-47 MPa7, EAB of 230-330 %11, IS of 561-122 kJ/mm2,8, and wear rates of 0.1-2.3 mg/million cycle9. Highly cross-linked UHMWPEs (without distinction of dose at this point) have decreased the incidence of peri-prosthetic osteolysis 87% over the last decade10 compared to conventional UHMWPE in total hips.

Our goal here was to develop methods by which therapeutic agents are incorporated into UHMWPE bearing surfaces but not increase any risk associated with their use while adding the benefit of antibacterial properties. However, it is also expected that any changes to the structure of the polymer may result in the compromise of one or more properties. There are UHMWPEs 1 Unpublished data for E1® Biomet




http://dx.doi.org/10.1038/s41551-017-0080

4

with a range of properties that are successfully used in different applications and in different patient populations according to the clinicians’ discretion as briefly explained above. Drug eluting UHMWPE with mechanical and tribological properties within the limits of conventional and highly-crosslinked UHMWPEs are expected to perform well as part of fully weight bearing prosthetic joint.

References 1. Hua, X. et al. Experimental validation of finite element modelling of a modular metal-on-

polyethylene total hip replacement. Proc. Inst. Mech. Eng. H 228, 682–692 (2014). 2. Van Den Heever, D. J., Scheffer, C., Erasmus, P. J. & Dillon, E. M. Contact stresses in a patient-

specific unicompartmental knee replacement. Clin. Biomech. 26, 159–166 (2011). 3. Villa, T., Migilavacca, F., Gastaldi, D., Colombo, M. & Pietrabissa, R. Contact stresses and fatigue

life in a knee prosthesis: comparison between in vitro measurements and computational simulation. J. Biomech. 18, 45–53 (2004).

4. Wang, A. et al. Orientation softening in the deformation and wear of ultra-high polyethylene. Wear 203–204, 230–241 (1997).

5. Kurtz, S. M. in UHMWPE Biomaterials Handbook, 3rd edn (Ed. Kurtz, S. M.) 45–55 (Elsevier, (2016).

6. Third AJRR Annual Report on Hip and Knee Arthroplasty Data 23–24 (American Joint Replacement Registry, 2016).

7. Pruitt, L. A. in Total Knee Arthroplasty: A Guide to Get Better Performance (eds Bellemans, J. etal.) 353–360 (Springer, 2005).

8. Oral, E. et al. A surface crosslinked UHMWPE stabilized by vitamin E with low wear and high fatigue strength. Biomaterials 31, 7051–7060 (2010).

9. Baykal, D., et al. Advances in tribological testing of artificial joint biomaterials using multidirectional pin-on-disk testers. J. Mech. Behav. Biomed. 31, 117–134 (2014).

10. 2015 Annual Report on National Joint Replacement Registry. Fig KT29 (Australian Orthopaedic Association, 2015)




http://dx.doi.org/10.1038/s41551-017-0080

5

Supplemental Figures

Supplementary Figure 1. SEM Micrograph and 3D reconstructed μ-CT of highly-eccentric, vancomycin eluting UHMWPE at 2 wt%, 4 wt %, 6 wt %, and 10 wt % initial drug content. Scale bar = 20 μm

Supplementary Figure 2. (a) Relation between porosity and initial drug content (wt %). Data are shown as mean ± sd. (b) Relation between accessible pore (%) from the face of the material and initial drug content (wt %). Data are shown as mean ± sd, n=6.

0 5 10 150

50

100

150

Initial drug content (wt %)

Acc

essi

ble

Pore

(%)

0 5 10 150

5

10

15

20

Initial drug content (wt %)

Poro

sity

(%)

(a) (b)




http://dx.doi.org/10.1038/s41551-017-0080

6

0 5 10 15 20 250

500

1000

1500

S. Epidermidis

Days

Area

of I

nhib

ition

(mm

2 ) VPEBC

0 5 10 15 20 250

200

400

600

800

Days

Area

of I

nhib

ition

(mm

2 ) VPEBC

S. aureus

(a) (b)

Supplementary Figure 3. Kirby-Bauer agar diffusion test of BC and V-PE against S aureus (a) and S epidermidis (b). Empty area around the samples where there was no visible bacteria growth is called area of inhibition. Data is shown as mean±s.d. (n=5).




http://dx.doi.org/10.1038/s41551-017-0080

7

0 100 200 300 4000.1

1

10

100

1000

VPE (Vancomycin)

Time (hr)

Elut

ion

Rate

(ug/

ml/h

r) PBSSF

0 100 200 300 4000.1

1

10

100

1000

BC (Vancomycin)

Time (hr)

Elut

ion

Rate

(ug/

ml/h

r) PBSSF

(a) (b)

0 100 200 300 4001

10

100

1000

RVPE (Vancomycin)

Time (hr)

Elut

ion

Rate

(ug/

ml/h

r) SFPBS

0 100 200 300 4000.1

1

10

100

RVPE (Rifampin)

Time (hr)

Elut

ion

Rate

(ug/

ml/h

r) PBSSF

(c) (d) Supplementary Figure 4. Antibiotic elution from VPE (vancomycin) (a), vancomycin-bone cement (BC) (vancomycin) (b), and RVPE (vancomycin) (c), and RVPE (Rifampin) (d) in synovial fluid (SF) and phosphate buffered saline (PBS).




http://dx.doi.org/10.1038/s41551-017-0080

8

Supplementary Figure 5. Elongation to break (%) of VPE and RVPE. Blue line represents the minimum known yield strength of clinically used UHMWPE as reported by Collier et al, 2003 [29]. Green line represents the mean value from 11 % vancomycin bone cement.

Supplementary Figure 6. Yield strength (MPa) of VPE and RVPE. Blue line represents the minimum known yield strength of clinically used UHMWPE as reported by Collier et al, 2003 [29].




http://dx.doi.org/10.1038/s41551-017-0080

9

Supplementary Figure 7. Wear Rate (mg/MC) of VPE and RVPE. Blue line represents the minimum known wear rate of 25 kGy gamma-irradiated UHMWPE (also called conventional UHMWPE).




http://dx.doi.org/10.1038/s41551-017-0080

10

Supplementary Figure 8. SEM Micrograph of various drugs incorporated in to ultra-high molecular weight polyethylene at 4 wt % initial drug concentration.

Supplementary Figure 9. Relation between drug polar surface area (PSA) / molecular volume (V) and log of drug elution rate. More polar compounds (PSA/MV > 0.3) had a higher elution rate at earlier time points compared to non-polar compounds (PSA/MV < 0.3). As elution times progressed, the elution rate of more polar drugs dropped more rapidly than the non-polar counterparts.




http://dx.doi.org/10.1038/s41551-017-0080

11

0 25 10020

25

30

35

40

Irradiation Dose (kGy)

UTS

(MPa

)

0 25 1000

20

40

60

80


Impa

ct S

treng

th (k

J/m

2 )

0 200 400 600 800 10000.1

1

10

100

1000

Time (hr)

Elut

ion

Rate

(ug/

ml/h

r) 0 kGy25 kGy100 kGy

0 25 1000

5

10

15


Wea

r Rat

e (m

g/M

C)

(a) (b)

(c) (d)

Supplementary Figure 10. Ultimate tensile strength (UTS, a), Impact strength (b), and wear rate (c) of VPE receiving various electron beam irradiation doses (0 kGy, 25 kGy, and 100 kGy). Data are derived from n=5 for UTS and impact strength. Data are deived from n=3 for wear rate. Data are displayed as means±s.d.




http://dx.doi.org/10.1038/s41551-017-0080

12

Positive

Control

0 kGy

25 kG

y

100 k

Gy

Negati

ve

Control

0.0

0.2

0.4

0.6

0.8

OD

600

(a) (b)

Supplementary Figure 11. Long-term antibacterial performance of VPE and RVPE. (a) Planktonic bacteria in the media after 24 hr incubation with V-PE that had been pre-eluted for 6 months and RV-PE that had been pre-eluted for 12 months. Negative control is fresh media, positive control is media with bacteria that had also been incubated for 24 hr. Data is displayed as mean ± s.d. (b) Immunofluorescence staining of grafted vancomycin on the surface of control UHMWPE, V-PE that was irradiated 0 ,25, and 100 kgy and had been pre-eluted for 6 months. Scale bars = 200 um




http://dx.doi.org/10.1038/s41551-017-0080

13

Supplementary Figure 12. Post-Mortem bioluminescent imaging of rabbit knee in the planktonic control group.

Control- Planktonic

Supplementary Figure 13. Sonication and reculturing of femur, tibia, meniscus, patella, and explants from control, VTBC, and VPE rabbits. Presence of bacteria in the media after sonication and reculturing for 24 hr was measured as absorbtion at 600 nm (OD600).

Control VTBC VPE0.0

0.2

0.4

0.6

0.8

1.0

OD6

00




http://dx.doi.org/10.1038/s41551-017-0080

14

Pre-op POD 3 POD 7 POD 210.0

0.5

1.0

1.5

2.0

2.5

Crea

tinin

e (m

g/dL

)

Pre-op POD 3 POD 7 POD 210

10

20

30

40

BU

N (m

g/dL

)


20

40

60

80

100

ALP

(IU/

L)

(a) (b)

(c) (d)

Supplementary Figure 14. Serum creatinine (a), Blood Urea Nitrogen (BUN) (b), serum alanine transaminase (ALT) (c), serum alkaline phosphatase (ALP) (d) of rabbits treated receiving V-PE plugs. Bloods were drawn and analyzed prior to surgery (Pre-op), post operative day 3 (POD 3), post- operative day 7 (POD 7), and post-operative day 21 (POD 21). Data are displayed as mean ± s.d.


50

100

150

ALT

(IU/

L)




http://dx.doi.org/10.1038/s41551-017-0080

15

Supplementary Figure 15. Ratio of eluted rifampin and vancomycin throughout elution time at different initial drugs loading ratio. Data are displayed as mean ± s.d., n=6

0 500 1000 15000

2

4

6

Vanc

o/Ri

fam

pin

Rele

ase

Rate

1.5:11.0:1

Time (hr)

2.0:12.5:1

Control- Biofilm

Supplementary Figure 16. Post-Mortem bioluminescent imaging of rabbit knee in the biofilm control group.




http://dx.doi.org/10.1038/s41551-017-0080

16

Control VTBC RVPE0

2.0106

4.0106

6.0106

8.0106

Tota

l Flu

x (p

/s)

Control VTBC RVPE0.0

0.2

0.4

0.6

0.8

OD

600

Supplementary Figure 17. Total bioluminescence flux (a) and absorption at 600 nm (OD600) (b), of rabbits in biofilm bacterial study receiving control UHMWPE plugs (control), antibiotic eluting bone cement (VTBC), or RVPE plugs (RVPE).

(a) (b)

Pre-op POD 3 POD 7 POD 210.0

0.5

1.0

1.5

2.0

2.5

Cre

atin

ine

(mg/

dL)


5

10

15

20

25BU

N (m

g/dL

)


50

100

150

ALT

(IU/

L)


10

20

30

40

50

ALP

(IU/

L)

Supplementary Figure 18. Serum creatinine (a), Blood Urea Nitrogen (BUN) (b), serum alanine transaminase (ALT) (c), serum alkaline phosphatase (ALP) (d) of rabbits treated receiving RV-PE plugs. Bloods were drawn and analyzed prior to surgery (Pre-op), post operative day 3 (POD 3), post-operative day 7 (POD 7), and post operative day 21 (POD 21). Data are displayed as mean ± s.d., n=5




http://dx.doi.org/10.1038/s41551-017-0080

17

(a)

(c)

(b)

Control RVPE0.0

0.2

0.4

0.6

BV/

TV

Supplementary Figure 19. Effect of RVPE on bony ongrowth in murine model. (a) Schematic and representative gross view of implantation of conventional-PE (control), RVPE, and stainless steel screw. (b) Representative micro-CT image of rat tibia receiving stainless screw after six weeks since implantation. The control UHMWPE (n=4) or RVPE (n=4) plugs were implanted transcondylarly on distal femur. Orange indicate hard tissue, yellow indicate soft tissue and empty space, red indicate screw. (c) Quantification of bone volume/total volume (BV/TV) of the bone surrounding the screws. No statistical significance difference between control and RVPE was observed.




http://dx.doi.org/10.1038/s41551-017-0080

18

Supplementary Table 1. Calculation of RV-PE to Clinically Relevant Vancomycin to Rifampin Ratio

Parameter Magnitude Unit

Vancomycin Dose (A) 1 15 mg/kg per 12 hr

Rifampin Dose (B)1 450 mg/kg per 12 hr

Serum trough concentration of rifampin (C) 2 1.875 ug/ml

Serum trough concentration of vancomycin (D) 3 20 ug/ml

Rifampin penetration to bone(E)4 100 %

Vancomycin penetration to bone (F)4 21 %

Rifampin concentration in infected bone (G=C*E) 1.875

Vancomycin Concentration in infected bone (H=D*F) 4.2

Vancomycin to Rifampin Ratio (H/G) 2.24

1. Osmon, D.R., et al. Diagnosis and Management of Prosthetic Joint Infection: Clinical Practice Guidelines by the Infectious Diseases Society of America, Clin Infect Diseases, 2013, 56, e1‐25 (2013).

2. Garnham, J. C., Taylor, T., Turner, P., Chasseaud, L.F. Serum concentrations and bioavailability of rifampicin and isoniazid in combination Br. J. clin. Pharmac, 1976, 3, 897‐902

3. Liu, C., et al. Clinical Practice Guidelines by the Infectious Diseases Society of America for the Treatment of Methicillin‐Resistant Staphylococcus Aureus Infections in Adults and Children. Clin. Infect. Dis., 52, 1‐38 (2011).

4. Spellberg, B., Lipsky, B.A. Diagnosis and Management of Prosthetic Joint Infection: Clinical Practice Guidelines by the Infectious Diseases Society of America, Clin. Infect. Dis., 54, 393‐407 (2012).




http://dx.doi.org/10.1038/s41551-017-0080

19

Supplementary Table 2. Calculation of RV-PE to Titanium-Bone interface Ratio


In Vivo

Synovial fluid volume in the knee1 3.0 ± 1.1 ml

Approximate tibial insert dimension ( L x W x H) 40 x 80 x 6 mm

Titanium-Bone interface surface area from tibial tray (approximate using 40 x 80 mm as contact area)

3.2 x 103 mm2

Titanium-Bone interface surface area from tibial tray (approximated to be twice the surface area from tibial tray)

6.4 x 103 mm2

Total titanium-bone interface area 9.6 x 103 mm2

In Vitro

Titanium-Bone Interface Area 7.1 mm2

RV-PE surface area 2.4 mm2

Media* 2.2 μL

1Kraus, V.B., Stabler, T. V., Kong, S.Y., Varju, G, McDaniel, G. Measurement of synovial fluid volume using urea. Osteoarthritis Cartilage, 15, 1217-1220 (2007). *1 ml media was used instead of 2.2 uL to ensure the bone, titanium, and RV-PE were all immersed. Using 1 ml instead of 2.2 uL was a worse case scenario because the eluted antibiotics were diluted by ~450 times.




http://dx.doi.org/10.1038/s41551-017-0080

20

Supplementary Table 3. Calculation of RV-PE to Screw-Bone interface Ratio for Murine Study


In Vivo

Approximate tibial insert dimension ( L x W x H) 40 x 80 x 6 mm

Approximate tibial insert surface area containing RVPE (A) 3440 mm2

Titanium-Bone interface surface area from tibial tray (approximate using 40 x 80 mm as contact area)

3.2 x 103 mm2

Titanium-Bone interface surface area from tibial tray (approximated to be twice the surface area from tibial tray)

6.4 x 103 mm2

Total titanium-bone interface area (B) 9.6 x 103 mm2

B/A 2.8

Murine Knee

Screw-Bone Interface Area 39.4 mm2

RV-PE surface area 14.2 mm2

Ratio 2.8




http://dx.doi.org/10.1038/s41551-017-0080

21

Supplementary Table 4. Implant Design Based on VPE and RVPE and Comparison of Their Mechanical and Wear Rate to Conventional UHMWPE, Highly-Crosslinked UHMWPE (HXLPE), and ASTM F648

Implant UTS (Mpa)

EAB (%) Impact Strength (kJ/mm2)

Wear Rate (mg/MC)

VPE (Brown = VPE) 32.9 ±1.9 245 ±22 79.5 ±3.4 9.6 ±1.3

RVPE (Red =RVPE, White = Highly-Crosslinked UHMWPE) 31.4 ±5.3 (RVPE) 34.0 ±3.0 (HXLPE)

228 ±22 (RVPE) 230 ±17 (HXLPE)

78.7 ±3.9 (RVPE) 62.2 ±1.6 (HXLPE)

9.0 ±1.0 (RVPE) 0.6 ±0.0 (HXLPE)

VPE+RVPE (Red=RVPE, Brown = VPE) 31.4 ±5.3 (RVPE) 32.9 ±1.9 (VPE)

228 ±22 (RVPE) 245 ±22 (VPE)

78.7 ±3.9 (RVPE) 79.5 ±3.4 (VPE)

9.0 ±1.0 (RVPE) 9.6 ±1.3 (VPE)

Conventional UHMWPE 46.2±1.5 414 ±21 119.3 ±2.3 9.3 ±0.80

Highly-Crosslinked UHMWPE (HXLPE) 34.0±3.0 230 ±17 62.2 ±1.57 0.6 ±0.03

ASTM F648 27 250 25 N/A




http://dx.doi.org/10.1038/s41551-017-0080

ulementar inormationimages.nature.com/.../2017/s41551-017-0080/extref/s41551-017-0080-s1.pdfeluting...

Documents