Biomechanical Characterization of an Osteoporotic Artificial Bone Model for the Distal Femur

Abstract

The treatment of osteoporotic distal femur fractures is still an unsolved problem of trauma surgery. The poor bone stock often leads to secondary loss of reduction and implant failure. Therefore, the development of new implants and their biomechanical testing is essential. In a previous study, we developed and initially characterized an artificial osteoporotic bone model of the distal femur. This follow-up study was performed to characterize this model in a biomechanical comparison. We investigated two different artificial bones: five foam cortical shell (Sawbones) and 10 custom-made artificial femoral condyles. Additionally, eight human femora were used for comparison. For biomechanical testing, two intramedullary nails (distal femur nail (DFN) and supracondylar nail (SCN)) were cyclically axial loaded in an AO 33 C2 unstable distal femoral fracture model. In our testing, the artificial bone showed a decrease in the axial stiffness of 27% for the SCN and 28% for the DFN compared to the human results. Also the number of cycles for a deformation of 2.5 mm was reduced by 55% (SCN) and 62% (DFN). This decrease was homogenous and caused by the relative high bone mineral density of the human specimen used. The modes of failure showed no difference between the artificial and human bones. Our customized artificial bone provides suitable results. In relation to the human bones classified as mildly osteoporotic, we assume that the biomechanical properties match to serve as an osteoporotic bone. Yet, we suggest to check transferability of the results with human material.

Keywords

biomechanics distal femur osteoporosis artificial bone

Get full access to this article

View all access options for this article.

References

Grass

Biewener

Rammelt

Zwipp

Retrograde Locking Nail Osteosynthesis of Distal Femoral Fractures with the Distal Femoral Nail (DFN), Unfallchirurg, 2002: 105: 298–314.

Chao

E.Y.

Inoue

Koo

T.K.

Kim

Y.H.

Biomechanical Considerations of Fracture Treatment and Bone Quality Maintenance in Elderly Patients and Patients with Osteoporosis, Clin. Orthop. Relat. Res, 2004: 425: 12–25.

Marti

Fankhauser

Frenk

Cordey

Gasser

Biomechanical Evaluation of the Less Invasive Stabilization System for the Internal Fixation of Distal Femur Fractures, J. Orthop. Trauma, 2001: 15: 482–487.

Zlowodzki

Williamson

Cole

P.A.

Zardiackas

L.D.

Kregor

P.J.

Biomechanical Evaluation of the Less Invasive Stabilization System, Angled Blade Plate, and Retrograde Intramedullary Nail for the Internal Fixation of Distal Femur Fractures, J. Orthop. Trauma, 2004: 18: 494–502.

Horn

Linke

Höntzsch

Gueorguiev

Schwieger

Angle Stable Interlocking Screws Improve Construct Stability of Intramedullary Nailing of Distal Tibia Fractures: A Biomechnical Study, Injury, 2009: 40: 767–771.

Lindahl

Lindgren

A.G.

Grading of Osteoporosis in Autopsy Specimens. A New Method, Acta Orthop. Scand., 1962: 32: 85–100.

Lindahl

. Mechanical Properties of Dried Defatted Spongy Bone, Acta Orthop. Scand., 1976: 47: 11–19.

Cristofolini

Viceconti

Mechanical Validation of Whole Bone Composite Tibia Models, J. Biomech., 2000: 33: 279–288.

Papini

Zdero

Schemitsch

E.H.

Zalzal

The Biomechanics of Human Femurs in Axial and Torsional Loading: Comparison of Finite Element Analysis, Human Cadaveric Femurs, and Synthetic Femurs, J. Biomech. Eng., 2007: 129: 12–19.

10.

Wähnert

Hoffmeier

K.L.

Stolarczyk

Fröber

Hofmann

G.O.

Mückley

Evaluation of a Customized Artificial Osteoporotic Bone Model of the Distal Femur, J. Biomater. Appl., 2010 (e-pub ahead of print).

11.

Wahnert

Hoffmeier

K.L.

Lehmann

Frober

Hofmann

G.O.

Muckley

Temperature Influence on DXA Measurements: Bone Mineral Density Acquisition in Frozen and Thawed Human Femora, BMC Musculoskelet. Disord, 2009: 10: 25.

12.

Milne

E.L.

Latta

L.L.

(1996). Biomechanical Testing of Femoral Intramedullary Devices, Iowa, Orthopaedic Biomechanics Laboratory, pp. 1–14.

13.

Schandelmaier

Stephan

Krettek

Tscherne

Distal fractures of the femur, Unfallchirurg, 2000: 103: 428–436.

14.

Khalafi

Curtiss

Hazelwood

Wolinsky

The Effect of Plate Rotation on the Stiffness of Femoral LISS: A Mechanical Study, J. Orthop. Trauma, 2006: 20: 542–546.

15.

Gueorguiev

Wahnert

Albrecht

Ockert

Windolf

Schwieger

Effect on Dynamic Mechanical Stability and Interfragmentary Movement of Angle-stable Locking of Intramedullary Nails in Unstable Distal Tibia Fractures: A Biomechanical Study, J. Trauma, 2010 (e-pub ahead of print).

16.

Faran

K.J.

Ichioka

Trzeciak

M.A.

Han

Medige

Moy

O.J.

Effect of Bone Quality on the Forces Generated by Compression Screws, J. Biomech., 1999: 32: 861–864.

17.

Seebeck

Goldhahn

Morlock

M.M.

Schneider

Mechanical Behavior of Screws in Normal and Osteoporotic Bone, Osteoporos. Int., 2005: 16: S107–S111.

18.

Stromsoe

Kok

W.L.

Hoiseth

Alho

Holding Power of the 4.5 mm AO/ASIF Cortex Screw in Cortical Bone in Relation to Bone Mineral, Injury, 1993: 24: 656–659.

19.

Drosos

Karnezis

I.A.

Bishay

Miles

A.W.

Initial Rotational Stability of Distal Tibial Fractures Nailed Without Proximal Locking: The Importance of Fracture Type and Degree of Cortical Contact, Injury, 2001: 32: 137–143.

20.

Schuller

Weninger

Tschegg

Jamek

Redl

Stanzl-Tschegg

Micromotion at the Fracture Site After Tibial Nailing with Four Unreamed Small-diameter Nails – A Biomechanical Study Using a Distal Tibia Fracture Model, J. Trauma, 2009: 66: 1391–1397.

21.

Schüller

Herndler

Weninger

Jamek

Redl

Tschegg

E.K.

Stiffness and Permanent Deformation of Extra-articular Distal Tibia Fractures Treated with Unreamed Small Diameter Intramedullary Nailing, Mater. Sci. Eng. C, 2008: 28: 1209–1216.

22.

Zlowodzki

Williamson

Zardiackas

L.D.

Kregor

P.J.

Biomechanical Evaluation of the Less Invasive Stabilization System and the 95-Degree Angled Blade plate for the Internal Fixation of Distal Femur Fractures in Human Cadaveric Bones with High Bone Mineral Density, J. Trauma, 2006: 60: 836–840.

23.

Snow

Thompson

Turner

P.G.

A Mechanical Comparison of the Locking Compression Plate (LCP) and the Low Contact-dynamic Compression Plate (DCP) in an Osteoporotic Bone Model, J. Orthop. Trauma, 2008: 22: 121–125.

24.

Höhle, P., Sternstein, W., Lum, J. and Rescher, A. (2006). Rommens, P.M. Biomechanical Comparison of Two Anglestable Retrograde Interlocked Femur Nails and the LISS in a Human 33A3 Osteotomy Model, In: 70. Deutscher Kongress für Orthopädie und Unfallchirurgie, Berlin, Germany.

25.

Ingman

A.M

. Retrograde Intramedullary Nailing of Supracondylar Femoral Fractures: Design and Development of a New Implant, Injury, 2002: 33: 707–712.

26.

Ito

Grass

Zwipp

Internal Fixation of Supracondylar Femoral Fractures: Comparative Biomechanical Performance of the 95-Degree Blade Plate and Two Retrograde Nails, J. Orthop. Trauma, 1998: 12: 259–266.

27.

Ito

Hungerbuhler

Wahl

Grass

Improved Intramedullary Nail Interlocking in Osteoporotic Bone, J. Orthop. Trauma, 2001: 15: 192–196.

28.

Koval

K.J.

Kummer

F.J.

Bharam

Chen

Halder

Distal Femoral Fixation: A Laboratory Comparison of the 95 Degrees Plate, Antegrade and Retrograde Inserted Reamed Intramedullary Nails, J. Orthop. Trauma, 1996: 10: 378–382.

29.

Meyer

R.W.

Plaxton

N.A.

Postak

P.D.

Gilmore

Froimson

M.I.

Greenwald

A.S.

Mechanical Comparison of a Distal Femoral Side Plate and a Retrograde Intramedullary Nail. J. Orthop. Trauma, 2000: 14: 398–404.