Kuhn F 1 , Clausing RJ 1 , Stiller A 1 , Fonseca Ulloa CA 1 , Foelsch C 2 , Rickert M 2 , Jahnke A 1
J Orthop. 2022 Jul 11:33:48-54. doi: 10.1016/j.jor.2022.07.003. eCollection 2022 Sep-Oct.
- Laboratory of Biomechanics, Department of Orthopaedics and Orthopaedic Surgery, Justus-Liebig-University Giessen, Klinikstrasse 29, 35392, Giessen, Germany.
- Department of Orthopaedics and Orthopaedic Surgery, University Hospital Giessen and Marburg (UKGM), Klinikstraße 33, 35392, Giessen, Germany.
Abstract
Background: Evaluation of the mechanical behavior of the microstructure of cancellous bone seems important for the understanding of the mechanical behavior of bone. Prevention and treatment of fragility fractures due to osteoporosis is a major challenge according to ageing population. A bone model might help to assess fracture risk. Measurement of single trabeculae of bone should give further information compared with bone densitometry alone. This study measures the mechanical properties of single cancellous trabeculae derived from human proximal humerus.
Methods: 34 single trabeculae dissected from human humeral heads were measured and evaluated mechanically. Trabeculae were fixed on microscope slides and geometrical data were reported during axial rotation of the specimens to measure the transverse section using computer aided design (CAD). The samples were subjected to a two-point bending test and were loaded with a measure-stamp at a defined distance. Force and deflection were measured by high-resolution sensors. The E-modulus was then calculated in combination with finite elements method simulation (FEM), using the previously obtained CAD-Data.
Results: The average E-modulus from 34 valid measurements of human humeral trabeculae was 1678 MPa with a range from 829 to 3396 MPa, which is consistent with existing literature. The planned additional validation of the measurement method using manufactured three-dimensional synthetic trabeculae with known mechanical properties showed an average elastic modulus of single trabeculae of 51.5 MPa, being two dimensions lower than the value reported in the datasheet of the plastic.
Conclusion: This newly developed, time and cost-efficient procedure allows the measurement of E-modulus in single trabeculae. Measurement of mechanic parameters of single trabeculae might give insights on mechanic behavior of bone and be relevant for the research of systemic bone diseases, complementing the existing data on bone-mineral-density. Further examination of single trabeculae of human cancellous bone should give an insight on the mechanical behavior of bone also considering systemic bone diseases.
Keywords: E-modulus; Fracture; Mechanic properties; Osteoporosis; Single bone trabecula; Synthetic cancellous bone.