Optimizing Fracture Management: Correlating the Physical and Mechanical Properties of Bone to Computed Tomography to Generate an Estimate of Bone Quality

Non-invasive estimates of bone quality are of great interest as they could potentially improve the diagnosis and treatments for bone disorders, such as osteoporosis, and could aid in preoperative planning of surgical interventions, improving patient outcomes in orthopaedic trauma.

Quantitative computed tomography (QCT) is currently being investigated as a method of estimating structural bone mineral content (sBMC) and, thus, bone quality. However, the reported correlations between QCT and sBMC have been variable and the relationships reported between sBMC and the apparent elastic modulus (E*) of bone have been even more variable.

A series of investigations are presented, relating QCT, sBMC, apparent density (ρ_APP) and the E* of bone. These studies were performed with the ultimate objective of determining the appropriateness of QCT as a predictor of the E* of bone and whether the E* of bone could be predicted from information regarding the sBMC and ρ_APP.

The repeatability of the CT scanner and the protocol for scanner calibration were studied to determine the optimal method for calibrating QCT scans. It was determined that the repeatability of the scanner was excellent and that the optimal method for scanner calibration was to image the standards in a volume of water equivalent to the soft tissue volume of the patient. However, as scans in air are easier to facilitate, an experimental protocol was developed to determine a relationship between the amount of soft tissue and the required correction to apply to the values of the calibration performed in air.

A linear trend was observed between the BMC determined from the QCT (BMC_HU) and the sBMC from ashing (R² = 0.49). No relationship was observed between the BMC_HU and the E* (R² < 0.10). A strong correlation was observed between the sBMC and the ρ_APP (R² = 0.97), as well as between the BMC and E* and the ρ_APP and the E* (R² = 0.71 and 0.77, respectively). However, there was still a relatively large amount of variation in the E* that was not explained by these relationships. It was concluded that parameters other than the sBMC and ρ_APP, such as the micro-architecture, need to be included in future studies for a better estimation of bone quality.

Year	Entry
1966	Weaver JK, Chalmers J. Cancellous bone: its strength and changes with aging and an evaluation of some methods for measuring its mineral content, I: age changes in cancellous bone. J Bone Joint Surg. March 1966;48A(2):289-298.
1985	Cann CE, Genant HK, Kolb FO, Ettinger B. Quantitative computed tomography for prediction of vertebral fracture risk. Bone. 1985;6(1):1-7.
1988	Ashman RB, Rho JY. Elastic modulus of trabecular bone material. J Biomech. 1988;21(3):177-181.
1991	Snyder SM, Schneider E. Estimation of mechanical properties of cortical bone by computed tomography. J Orthop Res. May 1991;9(3):422-431.
1998	Jiang Y, Zhao J, Augat P, Ouyang X, Lu Y, Majumdar S, Genant HK. Trabecular bone mineral and calculated structure of human bone specimens scanned by peripheral quantitative computed tomography: relation to biomechanical properties. J Bone Miner Res. November 1998;13(11):1783-1790.
1988	Cann CE. Quantitative CT for determination of bone mineral density: a review. Radiology. February 1988;166(2):509-522.
2006	Davies CM, Jones DB, Stoddart MJ, Koller K, Smith E, Archer CW, Richards RG. Mechanically loaded ex vivo bone culture system "Zetos": systems and culture preparation. Eur Cell Mater. January–June 2006;11:57-75.
1985	Gibson LJ. The mechanical behaviour of cancellous bone. J Biomech. 1985;18(5):317-328.
1984	Lipson SF, Katz JL. The relationship between elastic properties and microstructure of bovine cortical bone. J Biomech. 1984;17(4):231-240.
1996	Genant HK, Engelke K, Fuerst T, Glüer C, Grampp S, Harris ST, Jergas M, Lang T, Lu Y, Majumdar S, Mathur A, Takada M. Noninvasive assessment of bone mineral and structure: state of the art. J Bone Miner Res. June 1996;11(6):707-730.
1982	Gibson LJ, Ashby MF. The mechanics of three-dimensional cellular materialsthe mechanics of three-dimensional cellular materials. Proc R Soc Lon Ser-A. July 8, 1982;382(1782):43-59.
1988	Turner CH, Cowin SC. Errors induced by off-axis measurement of the elastic properties of bone. J Biomech Eng. August 1988;110(3):213-215.
1989	Mosekilde L, Bentzen SM, Ørtoft G, Jørgensen J. The predictive value of quantitative computed tomography for vertebral body compressive strength and ash density. Bone. 1989;10(6):465-470.
2006	Turner CH. Bone strength: current concepts. Annals NY Acad Sci. 2006;1068(1):429-446.
2002	Kopperdahl DL, Morgan EF, Keaveny TM. Quantitative computed tomography estimates of the mechanical properties of human vertebral trabecular bone. J Orthop Res. July 2002;20(4):801-805.
1987	Mosekilde L, Mosekilde L, Danielsen CC. Biomechanical competence of vertebral trabecular bone in relation to ash density and age in normal individuals. Bone. 1987;8(2):79-85.
2002	Wang X, Shen X, Li X, Agrawal CM. Age-related changes in the collagen network and toughness of bone [published correction appears in Bone. 2003;32(1):107]. Bone. 2002;31(1):1-7.
1991	Ciarelli MJ, Goldstein SA, Kuhn JL, Cody DD, Brown MB. Evaluation of orthogonal mechanical properties and density of human trabecular bone from the major metaphyseal regions with materials testing and computed tomography. J Orthop Res. May 1991;9(5):674-682.
2007	Nagaraja S, Lin ASP, Guldberg RE. Age-related changes in trabecular bone microdamage initiation. Bone. April 2007;40(4):973-980.
1999	Ebbesen EN, Thomsen JS, Beck-Nielsen H, Nepper-Rasmussen HJ, Mosekilde L. Lumbar vertebral body compressive strength evaluated by dual-energy X-ray absorptiometry, quantitative computed tomography, and ashing. Bone. December 1999;25(6):713-724.
1977	Carter DR, Hayes WC. The compressive behavior of bone as a two-phase porous structure. J Bone Joint Surg. 1977;59A(7):954-962.
2001	Guo XE. Mechanical properties of cortical and cancellous bone tissue. In: Cowin SC, ed. Bone Mechanics Handbook. 2nd ed. Boca Raton, FL: CRC Press; 2001:chap 10.
2003	Jones DB, Broeckmann E, Pohl T, Smith EL. Development of a mechanical testing and loading system for trabecular bone studies for long term culture. Eur Cell Mater. January–June 2003;5:48-60.
1960	Currey JD. Differences in the blood-supply of bone of different histological types. Q J Microsc Sci. September 1960;101(3):351-370.
2006	Teo JCM, Si-Hoe KM, Keh JEL, Teoh SH. Relationship between CT intensity, micro-architecture and mechanical properties of porcine vertebral cancellous bone. Clin Biomech (Bristol, Avon). March 2006;21(3):235-244.
1985	McBroom RJ, Hayes WC, Edwards WT, Goldberg RP, White AA III. Prediction of vertebral body compressive fracture using quantitative computed tomography. J Bone Joint Surg. 1985;67A(8):1206-1214.
1990	Choi K, Kuhn JL, Ciarelli MJ, Goldstein SA. The elastic moduli of human subchondral, trabecular, and cortical bone tissue and the size-dependency of cortical bone modulus. J Biomech. 1990;23(11):1103-1113.
1998	Augat P, Link T, Lang TF, Lin JC, Majumdar S, Genant HK. Anisotropy of the elastic modulus of trabecular bone specimens from different anatomical locations. Med Eng Phys. March 1998;20(2):124-131.
2001	Grant JP, Oxland TR, Dvorak MF. Mapping the structural properties of the lumbosacral vertebral endplates. Spine. April 15, 2001;26(8):889-896.
1990	Lotz JC, Gerhart TN, Hayes WC. Mechanical properties of trabecular bone from the proximal femur: a quantitative CT study. J Comput Assist Tomogr. January–February 1990;14(1):107-114.
1989	Hvid I, Bentzen SM, Linde F, Mosekilde L, Pongsoipetch B. X-ray quantitative computed tomography: the relations to physical properties of proximal tibial trabecular bone specimens. J Biomech. 1989;22(8-9):837-844.
2007	Öhman C, Baleani M, Perilli E, Dall’Ara E, Tassani S, Baruffaldi F, Viceconti M. Mechanical testing of cancellous bone from the femoral head: experimental errors due to off-axis measurements. J Biomech. 2007;40(11):2426-2433.
1988	Schaffler MB, Burr DB. Stiffness of compact bone: effects of porosity and density. J Biomech. 1988;21(1):13-16.
1989	Esses SI, Lotz JC, Hayes WC. Biomechanical properties of the proximal femur determined in vitro by single‐energy quantitative computed tomography. J Bone Miner Res. October 1989;4(5):715-722.
2004	Kaneko TS, Bell JS, Pejcic MR, Tehranzadeh J, Keyak JH. Mechanical properties, density and quantitative CT scan data of trabecular bone with and without metastases. J Biomech. April 2004;37(4):523-530.
2003	Kaneko TS, Pejcic MR, Tehranzadeh J, Keyak JH. Relationships between material properties and CT scan data of cortical bone with and without metastatic lesions. Med Eng Phys. July 2003;25(6):445-454.
2001	Turner CH, Burr DB. Experimental techniques for bone mechanics. In: Cowin SC, ed. Bone Mechanics Handbook. 2nd ed. Boca Raton, FL: CRC Press; 2001:chap 7.
1998	Majumdar S, Kothari M, Augat P, Newitt DC, Link TM, Lin JC, Lang T, Lu Y, Genant HK. High-resolution magnetic resonance imaging: three-dimensional trabecular bone architecture and biomechanical properties. Bone. May 1998;22(5):445-454.
1967	Bell GH, Dunbar O, Beck JS, Gibb A. Variations in strength of vertebrae with age and their relation to osteoporosis. Calcif Tiss Res. 1967;1(1):75-86.
2007	Bessho M, Ohnishi I, Matsuyama J, Matsumoto T, Imai K, Nakamura K. Prediction of strength and strain of the proximal femur by a CT-based finite element method. J Biomech. 2007;40(8):1745-1753.
1995	Rho JY, Hobatho MC, Ashman RB. Relations of mechanical properties to density and CT numbers in human bone. Med Eng Phys. July 1995;17(5):347-355.
1973	Hounsfield GN. Computerized transverse axial scanning (tomography), I: description of system. Br J Radiol. 1973;46:1016-1022.
2001	Lakes R. Viscoelastic properties of cortical bone. In: Cowin SC, ed. Bone Mechanics Handbook. 2nd ed. Boca Raton, FL: CRC Press; 2001:chap 11.
2005	Yeung DKW, Griffith JF, Antonio GE, Lee FKH, Woo J, Leung PC. Osteoporosis is associated with increased marrow fat content and decreased marrow fat unsaturation: a proton MR spectroscopy study. J Magn Reson Imaging. August 2005;22(2):279-285.
1992	Besl PJ, McKay ND. A method for registration of 3-D shapes. IEEE Trans Pattern Anal Mach Intell. February 1992;14(2):239-256.

Year

Entry

1966

Weaver JK, Chalmers J. Cancellous bone: its strength and changes with aging and an evaluation of some methods for measuring its mineral content, I: age changes in cancellous bone. J Bone Joint Surg. March 1966;48A(2):289-298.

1985

Cann CE, Genant HK, Kolb FO, Ettinger B. Quantitative computed tomography for prediction of vertebral fracture risk. Bone. 1985;6(1):1-7.

1988

Ashman RB, Rho JY. Elastic modulus of trabecular bone material. J Biomech. 1988;21(3):177-181.

1991

Snyder SM, Schneider E. Estimation of mechanical properties of cortical bone by computed tomography. J Orthop Res. May 1991;9(3):422-431.

1998

Jiang Y, Zhao J, Augat P, Ouyang X, Lu Y, Majumdar S, Genant HK. Trabecular bone mineral and calculated structure of human bone specimens scanned by peripheral quantitative computed tomography: relation to biomechanical properties. J Bone Miner Res. November 1998;13(11):1783-1790.