gms | German Medical Science

Deutscher Kongress für Orthopädie und Unfallchirurgie
74. Jahrestagung der Deutschen Gesellschaft für Unfallchirurgie
96. Tagung der Deutschen Gesellschaft für Orthopädie und Orthopädische Chirurgie
51. Tagung des Berufsverbandes der Fachärzte für Orthopädie und Unfallchirurgie

26. - 29.10.2010, Berlin

Anatomical and biomechanical properties of the patellofemoral joint – preliminary report

Meeting Abstract

  • M. Bilici - Universitätsspital Basel, Klinik für Orthopädische und Traumatologische Chirurgie, Basel, Switzerland
  • D. Wirz - Universität Basel, Clinical Morphology & Biomedical Engineering, Laboratory Of Biomechanics & Biocalorimetry, Basel, Switzerland
  • B. Goepfert - Universität Basel, Clinical Morphology & Biomedical Engineering, Laboratory Of Biomechanics & Biocalorimetry, Basel, Switzerland
  • G. Pagenstert - Universitätsspital Basel, Department Orthopädie, Basel, Switzerland
  • M. Müller-Gerbl - Anatomisches Institut der Universität Basel, Switzerland
  • V. Valderrabano - Universitätsspital Basel, Orthopädische Klinik, Bewegungszentrum Untere Extremität, Basel, Switzerland

Deutscher Kongress für Orthopädie und Unfallchirurgie. 74. Jahrestagung der Deutschen Gesellschaft für Unfallchirurgie, 96. Tagung der Deutschen Gesellschaft für Orthopädie und Orthopädische Chirurgie, 51. Tagung des Berufsverbandes der Fachärzte für Orthopädie. Berlin, 26.-29.10.2010. Düsseldorf: German Medical Science GMS Publishing House; 2010. DocIN23-1657

DOI: 10.3205/10dkou146, URN: urn:nbn:de:0183-10dkou1460

Published: October 21, 2010

© 2010 Bilici et al.
This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by-nc-nd/3.0/deed.en). You are free: to Share – to copy, distribute and transmit the work, provided the original author and source are credited.


Outline

Text

Objective: Isolated or accentuated patellofemoral arthrisis is rare in a non-traumatic setting. Little is known about aetiology, pathogenesis and long-term results of different therapeutic modalities. The biomechanics of the patella is complex with dynamically changing forces on each ligament and the joint surfaces. One hypothesis for the aetiology of patellofemoral accentuated arthrosis is the malalignement of the patella. Our aim is to investigate the long term impact of these forces on the micro- and macro-morphology of the patella. This will lead to a better understanding of the pathophysiological changes during alterations of one of these structures.

Methods: This study was conducted on 10 human formalin fixated and 20 human native patellae. We investigated the patellae with CT-Osteoabsorptiometry (CT-OAM; Siemens Somatom-Sensation-CT), micro-CT-scans, micro-indentation hardness tests of the subchondral bone plate and histology for morphometric analysis. CT-OAM has been shown to be strongly correlated with bone mineralization. Micro-CT scans have been performed in a skyscan-1174-Micro-CT for 3D-Analysis of subchondral trabecular structures with a resolution of 35um and a slicing distance of 0.4 mm. The subchondral bone plate was analyzed at the same template spots by force-to-failure measurements with a microindenter machine (MTS® Corp., Oak Ridge, TN). Finally histological morphometric analyses have been prepared in 10um slices and three different dyes (Masson-Goldner, Romanovsky and Safranin-O) to represent the tissue contents (cartilage, subchondral bone plate, subchondral trabecular formation).

Results and conclusions: The preliminary data show a strong positive correlation between the subchondral bone mineralisation, the subchondral trabecular mineralisation and the rigidity of the subchondral bone plate. However there was no correlation between the subchondral bone mineralisation with the density of the subchondral trabecular structures. The areas of highest subchondral mineralization and rigidity displayed thinner layers of cartilage in the histological analysis. On the other hand the areas of lower mineralization and lower rigidity represent joint surfaces with intact cartilage layers and reduced trabecular bone rigidity.

This could mean that bone with areas of overuse and cartilage loss develop a subchondral bone plate with higher stiffness and trabecular density as typical signs of arthritis with sclerosis. But in areas of insufficient joint loads the cartilage layer is intact with a thinner and less mineralized subchondral bone plate with the microanatomically correlated loss of trabecular rigidity.

The data of our cohort support the hypothesis of malalignement as major pathogenic factor for the aetiology of patellofemoral arthritis.