gms | German Medical Science

Deutscher Kongress für Orthopädie und Unfallchirurgie (DKOU 2018)

23.10. - 26.10.2018, Berlin

Microstructural bone remodeling of the adolescent subchondral bovine bone

Meeting Abstract

  • presenting/speaker Shahed Taheri - Universitätsmedizin Göttingen, Klinik f. Unfallchirurgie, Orthopädie u. Plast. Chirurgie, Göttingen, Germany
  • Thomas Winkler - Technische Universität Hamburg-Harburg, Institute of Biomechanics, Hamburg, Germany
  • Lia Sabrina Schenk - Technische Universität Hamburg-Harburg, Institute of Biomechanics, Hamburg, Germany
  • Carl Neuerburg - Munich University Hospital LMU, Department of Traumatology and Orthopaedic Surgery, München, Germany
  • Sebastian Felix Baumbach - Munich University Hospital LMU, Department of Traumatology and Orthopaedic Surgery, München, Germany
  • Jozef Zustin - Universitätsklinikum Hamburg Eppendorf, Pathology, Hamburg, Germany
  • Wolfgang Lehmann - Universitätsmedizin Göttingen, Klinik f. Unfallchirurgie, Orthopädie u. Plast. Chirurgie, Göttingen, Germany
  • Arndt F. Schilling - Universitätsmedizin Göttingen, Klinik f. Unfallchirurgie, Orthopädie u. Plast. Chirurgie, Göttingen, Germany

Deutscher Kongress für Orthopädie und Unfallchirurgie (DKOU 2018). Berlin, 23.-26.10.2018. Düsseldorf: German Medical Science GMS Publishing House; 2018. DocPT20-929

doi: 10.3205/18dkou720, urn:nbn:de:0183-18dkou7209

Veröffentlicht: 6. November 2018

© 2018 Taheri et al.
Dieser Artikel ist ein Open-Access-Artikel und steht unter den Lizenzbedingungen der Creative Commons Attribution 4.0 License (Namensnennung). Lizenz-Angaben siehe http://creativecommons.org/licenses/by/4.0/.


Gliederung

Text

Objectives: Subchondral bone (SCB) is a complex osseous structure that is located in the close adjacency of articular cartilage. Despite growing evidence that suggests SCB's early role in osteoarthritis (OA) development, its exact association with OA is incompletely understood. The major risk factor for (OA) is age. To understand age-related microstructural and material changes of the subchondral zone (SCZ) at a potentially interesting time frame of youth and in early adulthood, herein we examine the microstructure and material properties of the medial condyle of the femur in calves and cattle with the aid of histomorphometry, µCT analyses, and energy-dispersive X-ray spectroscopy (EDX).

Methods: 18 bone specimens from three calves (3 month of age) and three cattle (18 month of age) were obtained. They were fixed and subsequently stored in phosphate buffered saline (PBS) at +4°C. Histomorphometric analysis was carried out by means of Masson-Goldner staining. The thickness of particular layers was measured using an image processing software at three fixed spots. Micro-CT scans were performed (µ-CT 35, SCANCO Medical AG, Switzerland), at a voxel resolution of 3.5 µm, a source voltage of 70 kVp and an intensity of 114 µA. EDX was carried out using a EVO LS 15 electron microscope (Carl Zeiss AG, Germany). Starting from the calcified cartilage, measurements were taken every 50 µm within the first 200 µm of depth, and every 100 µm from 200 to 700 µm. Statistical analysis was conducted using one-way ANOVA and Bonferroni post hoc testing (p<0.05).

Results and conclusion: The mean thickness of the calcified cartilage (CC), as well as the whole subchondral layer was significantly higher in cattle compared to calves (p<0.01). The bone volume density (BV/TV), the trabecular thickness (Tb.Th.), and the degree of anisotropy (DA) were significantly higher in cattle, while trabecular separation (Tb.Sp.) demonstrated a considerable age-related decrease. The EDX element analysis showed that calcium (Ca) and phosphorous (P) had significantly higher concentrations in cattle, while carbon (C) content dropped with age. The mean values of Ca/P ratio were 1.59±0.023 and 1.64±0.018 for calves and cattle, respectively (p<0.01).

The age-related ossification of the subchondral bone and the calcified cartilage in healthy bovine samples was shown in the scope of this study. A decreased connectivity, coupled with increases in BV/TV and Tb.Th. suggests a remodeling mechanism in which cavities are subsequently filled via a union of trabecular bone elements. Interestingly, the most perceptible depth-dependent behavior of the chemical compositions was observed within the first 150 µm of tidemark, corresponding to the calcified cartilage region. As the subchondral zone plays a distinct role in the development of osteoarthritis, these early changes in subchondral architectural and material properties may play a role for later development of the osteochondral area and therefore for the aging joint.