dc.description.abstract | A loading-unloading apparatus that combined clinical ultrasound and load cell was built to investigate the mechanical properties of the plantar heel pad tissues in living activities. A 5-10 MHz 26mm compact linear array transducer was used to record the continuous B-mode images of the deformation of the plantar heel pad, and then derive their mechanical properties. Elastography of the plantar heel pad were constructed to investigate the biomechanics during normal walking condition. The boundaries of each layer of the soft tissue were estimated by tracking either by the maximum gradient of gray scale or by the k-value of correlative deformation.
Axial strain, lateral strain, elastic modulus, and the ratio of axial strain to lateral strain were computed in various layers of tissues. Compressive index, stiffness, loading and unloading strain rate were taken into account for the quantification of mechanical properties of soft tissues. The elastic modulus of heel pad, at eight different depths calculated, were 124.8 (19.7) kPa, 119.6 (13.7) kPa, 92.6 (32.1) kPa, 73.0 (30.6) kPa, 62.5 (15.4) kPa, 62.2 (14.7) kPa, 55.0 (14.1) kPa and 58.4 (10.2) kPa respectively, which resulted in an equivalent elastic modulus of 39.5 (7.401) kPa. Moreover, the overall stiffness, compressive index, loading and unloading strain rate measured were about 247.5 (58.7) kPa, 0.593 (0.008), 0.315 (0.0387) s-1 and -0.292 (0.0524) s-1 respectively.
The macro-chamber near the calcaneus has a lower stiffness than the micro-chamber next to the plantar skin. Under the action of larger strain rate, the macro-chamber reduces shock from ground effectively. Because of hysteresis, the larger loading strain rate, results a steeper slope in stress-strain curve. There is a large lateral deformation in the transverse scanning plane of the calcaneus, and the amount of lateral distortion is affected by boundary condition and the collagen fibrous spacing. | en |
dc.relation.reference | 1. Aerts P, Ker RF, De Clercq. The mechanical Properties of the Human Heel pad: A Paradox Resolved. J. Biomech. 1995; 28; 1299-1308
2. Aerts P, Ker RF, De Clercq D, Ilsley DW. The effects of isolation on the mechanics of the human heel pad. J Anat. 1996; 188: 417-423
3. Bennett MB, Ker AR. The mechanical properties of the human subcalcaneal fat pad in compression. J Anat. 1990; 171: 131-138
4. Bercoff J, Chaffai S, Tanter M, Sandrin L, Catheline S, Fink M, Gennisson JL, Meunier M. In Vivo Breast Tumor Detection Using Transient Elastography. Ultrasound Med. Biol. 2003; 29; 1387–1396
5. Bilgen M, Srinivasan S, Lachman LB, Ophir J. Elastography Imaging of Small Animal Oncology Models: A Feasibility Study. Ultrasound Med. Biol. 2003; 29; 1291–1296
6. Blechschmidt E. The Structure of the Calcaneal Padding. Foot Ankle. 1982; 2; 260-283
7. Bojsen-Moller F, Jorgensen U. The plantar soft tissue: functional anatomy and clinical applications. In: Jahss MM, editor. Disorders of the foot and ankle, medical and surgical management. Philadelphia: Saunders; 1991, 532-540
8. Cavanagh PR. Plantar Soft Tissue thickness during Ground Contact in Walking. J Biomech. 1999; 32; 623–628
9. Dickinson RJ, Hill CR. Measurement of Soft Tissue Motion Using Correlation Between A-scans. Ultrasound Med. Biol. 1982; 8; 263–271
10. Dreeben S, Thomas PBM, Noble PC, Tullos HS. A new method for radiography of weight-bearing metatarsal heads. Clin Orthop 1987; 224: 260-267.
11. Erdemir A, Viveiros ML, Ulbrecht JS, Cavanagh PR. Hyperelastic Properties of Heel Pads of Diabetic Subjects and Controls in Vivo: An Inverse Finite Element Model of Indentation. In press.
12. Fung YC. The Meaning of the Constitutive Equation; Biomechanics Mechanical Properties of Living Tissues, 2nd ed. New York: Springer-Verlag; 1993; 23-65
13. Gefen A, Ravid MM, Itzchak Y. In vivo biomechanical behavior of the human heel pad during the stance phase of gait. J Biomech. 2001; 34: 1661-1665.
14. Gooding GAW, Stess RM, Graf PM, Moss KM, Louie KS, Grunfeld C. Evidence for loss of foot pad thickness in diabetic and its relationship to ulceration of the foot .Invest Radiol. 1986;21: 45-48
15. Hall TJ, Zhu Y, Spalding CS. In Vivo Real-Time Freehand Palpation Imaging. Ultrasound Med. Biol. 2003; 29; 427–435
16. Hiltawsky KM, Kruger M, Starke C, Heuser L, Ermert H, Jensen A. Freehand Ultrasound Elastography of Breast Lesions: Clinical Results. Ultrasound Med. Biol. 2001; 27; 1461–1469
17. Hsu TC, Lee YS, Shau YW. Biomechanics of the heel pad for type II diabetic patients. Clin. Biomech. 2002; 17; 291–296
18. Hsu TC, Tsai WC, Chen CPC, Shau YW, Wang CL, Chen MJL, Chang KJ. Effects of Aging on the Plantar Soft Tissue Properties Under the Metatarsal Heads at Different Impact Velocities. In press.
19. Hsu TC, Wang CL, Tsai WC, Kuo JK, Tang FT. Comparison of the mechanical properties of the heel pad between young and elderly adults. Arch Phys Med Rehabil. 1998; 79: 1101-1104
20. Jorgensen U. Achillodynia and loss of heel pad shock absorbency. Am J Sports Med. 1985; 13: 128-132
21. Jorgensen U, Ekstrand J. Significance of heel pad confinement for the shock absorption at heel strike. Int J Sports Med. 1988; 9: 468-473
22. Konofagou E, Ophir J. A New Elastographic Method for Estimation and Imaging in Lateral Displacements, Lateral Strains and Posiion’s Ratio in Tissue. Ultrasound Med. Biol. 1998; 24; 1183–1199
23. Kashioka J, Ohya A, Itoh T, Akiyama I, Nakajima M. Tissues hardness Imaging Method Based on Changeability of Interference Patterns on Statistically Pressuring Conditions. Jpn. Soc. Ultrasound Med Proc. 1992; 322
24. Kinoshita H, Francis, Murase T, Kawai S, Ogawa Y. The Mechanical Properties of the Heel Pad in Elderly Adults. Eur J Appl Physiol 1996; 43; 404-409
25. Langevin H, Konofagou E, Badger J, Churchill D, Fox J, Ophir J, Garra B. Tissue Displacements During Acupunature Using Ultrasound Elastography Techniques. Ultrasound Med. Biol. 2004; 30; 1173–1183
26. Ophir J, Cespedes I, Ponnekanti H, Yazdi Y, Li X. Elastography: A Quantitative Method for Imaging The Elasticity of Biological Tissues. Ultrason. Imaging 1991; 13; 111-134
27. Ophir J, Cespedes I, Garra B, Ponnekanti H, Huang Y, Maklad N. Elastography: ultrasonic Imaging of Tissue Strain and Elastic Modulus in Vivo. Eurp. J. ultrasound. 3 ;1996; 49-70
28. Ophir J, Garra B, Kallel F, Konofagou E, Krouskop T, Righetti R, Varghese T. Elastographic Imaging. Ultrasound Med. Biol. 2000; 26;Supple.1; S23–S29
29. Righetti R, Ophir J, Srinivasan S, Krouskop TA. The feasibility of using elastography for imaging the Poisson's ratio in porous media. Ultrasound Med. Biol. 2004; 30; 215–228
30. Rome K, Webb P, Unsworth A, Haslock I. Heel Pad Stiffness in Runners with Plantar Heel Pain. Clin. Biomech. 2001; 16; 901-905
31. Shau YC, Wang CL, Shieh JY, Hau TC. Noninvasive Assessment of the Viscoelasticity of Peripheral Arteries. Ultrasound Med. Biol. 1999; 25; 1377–1388
32. Steinbach HL, Russell W. Measurement of the heel-pad as an aid to diagnosis of acromegaly. Radiology 1964; 82: 418-422
33. Techavipoo U, Varghese T, Zagzebski JA, Chen Q, Liu W. Semiautomated Thermal Lesion Segmentation for Thereedimensional Elastographic Imaging. Ultrasound Med. Biol. 2004; 30; 655–664
34. Tsai WC, Wang CL, Hsu TC, Hsieh FJ. The mechanical properties of the human heel pad .Formosan Journal of medicine. 1997; 4: 417-423.
35. Turgut A, Gokturk E, Kose N, Seber S, Hazer B, Gunal I. The relationship of heel pad elasticity and plantar heel pain. Clin Orthop Rel Res. 1999; 360: 191-196
36. Vogt M, Scharenberg S, Scharenberg R, Hoffmann K, Altmeyer P, Ermert H. In Vivo Evaluation and Imaging of Skin Elasticity Applying High Frequency (22MHz) Ultrasound. 2002 IEEE Ultrason. Symp. Proc.; 1819–1822
37. Vogt M, Scharemberg S, Scharemberg R, Hoffmann K, Altmeyer P, Ermert H. A High Frequency Ultrasound Elastography System for in Vivo Skin Elasticity Imaging. Proc. World Cong. On Ultrason. 2003; 393–396
38. Wang CL, Hsu TC, Shau YW, Shieh JY, Hsu KH. Ultrasonographic measurement of the mechanical properties of the sole under the metatarsal heads. J Orthop. Res. 1999; 17; 709–713
39. Zheng YP, Choi YKC, Wong K. Biomechanical Assessment of Plantar Foot Tissue in Diabetic Patients Using an Ultrasound Indentation System. Ultrasound Med. Biol. 2000; 26; 451–456
40. 許智欽; 足跟脂肪墊之機械特性; 長庚大學臨床醫學研究所博士論文; 2002
41. 何奕樺; 應變速率對足部軟組織機械特性之研究; 台灣大學應用力學研究所碩士論文; 2001
42. 陳佳琳; 貼紮對足跟墊避震能力之影響; 台灣大學物理治療學研究所碩士論文; 2004 | zh_TW |