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DOI: 10.1055/s-0038-1632754
Measurement of bone surface strains on the sheep metacarpus in vivo and ex vivo
This study was supported by Med Tech Grant No. 3895.1 (Commission of Technology and Innovation) from the Swiss government and Sulzer Orthopaedics. The authors would like to thank the animal caretakers of the AO Research Institute in Davos, Switzerland for their support during training and experiments with the animals.
Publication History
Received
14 June 2002
Accepted
04 July 2002
Publication Date:
08 February 2018 (online)
Summary
Bone surface strains were measured on the dorsal ovine metacarpus during normal locomotion on a treadmill at different walking speeds to determine physiological strain levels. These measured strains were related to the strains measured in an ex vivo model of the sheep forelimb with two types of load application: loading by two Schanz-screws and loading via the radius. In vivo, the average surface strains were found to be dependent upon body weight as well as the walking speed. The orientation of the peak principal strain corresponded to the longitudinal axis of the bone. Ex vivo, loads applied via Schanz screws in the screw-loading model lead to strains on the dorsal metacarpus that corresponds to strains experienced in vivo during intermittent peak loads. Screw loading imparted primarily a bending load to the metacarpus, with the dorsal aspect in compression and the palmar aspect in tension. Loads, applied via the radius and the hoof in the radius-loading model, resulted in bone surface strains comparable to those measured during slow walking in vivo. In both ex vivo loading situations, peak strain orientation was parallel to the longitudinal axis of the sheep metacarpus. In conclusion, the results show that although the ex vivo loading models do not exactly replicate the load experienced in vivo, the magnitude and orientation of the principal strains on the dorsal metacarpus are within the range of strains occurring during normal physiological loading. These data validate the physiological significance of the ex vivo model and aid in understanding effects of mechanical loading on interstitial fluid flow and mass transport through bone.
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References
- 1 Cordey J, Gautier E. Strain Gauges Used in the Mechanical Testing of Bones. Part II: “In Vitro” and “in Vivo” Technique. Injury, Int J Care of the Injured 1999; 30 (Suppl. 01) A14-A20.
- 2 Cordey J, Schnetzer M, Brennwald J, Regazzoni P, Perren SM. Direct in vivo Measurements of Torque and Bending in Sheep Tibiae. Uhthoff H. K. Current concepts of internal fixation of fractures. Berlin Heidelberg New York: Springer Verlag; 1980: 78-87.
- 3 Gatzka C, Schneider E, Knothe MLTate, Knothe U, Niederer P. A Novel Ex Vivo Model for Investigation of Fluid Displacements in Bone After Endoprosthesis Implantation. J Material Science: Materials in Medicine 1999; 10: 801-6.
- 4 James E, Dally W, Riley WF. Strain-measurement methods and instrumentation. Experimental stress analysis. New York: McGraw- Hill; 1965: 426-9.
- 5 Knothe MLTate, Knothe U. An Ex Vivo Model to Study Transport Processes and Fluid Flow in Loaded Bone. J Biomechanics 2000; 33 (02) 247-54.
- 6 Knothe MLTate, Knothe U, Niederer P. Experimental Elucidation of Mechanical Load- Induced Fluid Flow and Its Potential Role in Bone Metabolism and Functional Adaptation. Am J Medical Sciences 1998; 316 (03) 189-95.
- 7 Knothe MLTate, Niederer P, Knothe U. In Vivo Tracer Transport Through the Lacunocanalicular System of Rat Bone in an Environment Devoid of Mechanical Loading Bone. 1998; 02 (Feb): 107-17.
- 8 Lanyon LE. Analysis of Surface Bone Strain in the Calcaneus of Sheep During Normal Locomotion. J Biomechanics 1973; 06: 41-9.
- 9 Lanyon LE, Baggott DG. Mechanical Function As an Influence on the Structure and Form of Bone. J Bone and Joint Surgery. Brit vol 1976; 58-B (04) 436-43.
- 10 Lanyon LE, Bourn S. The Influence of Mechanical Function on the Development and Remodeling of the Tibia. An Experimental Study in Sheep. J Bone and Joint Surgery. Am vol 1979; 61 (02) 263-73.
- 11 Lanyon LE, Magee PT, Baggott DG. The Relationship of Functional Stress and Strain to the Processes of Bone Remodelling. An Experimental Study on the Sheep Radius. J Biomechanics 1979; 12 (08) 593-600.
- 12 Lanyon LE, Paul IL, Rubin CT, Trasher EL, DeLaura R, Rose RM, Radin EL. In Vivo Strain Measurements From Bone and Prosthesis Following Total Hip Replacement. J Bone and Joint Surgery. Am Vol 1981; 63-A (06) 989-1001.
- 13 Lanyon LE, Smith RN. Bone Strain in the Tibia During Normal Quadrupedal Locomotion. Acta Orthopaedica Scandinavia 1970; 41 (03) 238-48.
- 14 Lanyon LE, Smith SR. Measurements of Bone Strain in the Walking Animal. Res Veterinary Science 1969; 10: 93-4.
- 15 Levenston ME, Beaupre GS, van der Meulen MC. Improved Method for Analysis of Whole Bone Torsion Tests. J Bone and Mineral Research 1994; 09 (09) 1459-65.
- 16 O’Connor JA, Lanyon LE, MacFie H. The Influence of Strain Rate on Adaptive Bone Remodelling. J Biomechanics 1982; 15 (10) 767-81.
- 17 Rubin CT, Lanyon LE. Regulation of Bone Mass by Mechanical Strain Magnitude. Calcified Tissue International 1985; 37: 411-7.
- 18 Tami AE, Nasser P, Verborgt O, Schaffler MB, Knothe MLTate. The role of interstitial fluid flow in the remodeling response to fatigue loading. J Bone Min Res 2002; 17 (11) 2030-7.