On the Influence of Mechanical Conditions on Osteochondral HealingZully M Ritter1121.11.1.131.1.241.2561.2.1781.2.1.11.2.1.1.11.2.1.1.2910111.2.1.1.31.2.1.1.4121.2.1.1.5131.2.1.2141.2.1.2.11.2.1.2.2151.2.1.2.31617181.2.2191.2.2.11.2.2.1.11.2.2.1.2201.2.2.1.3211.2.2.1.41.2.2.21.2.2.2.1221.2.2.2.2231.2.2.2.3241.2.2.2.4251.2.2.3261.2.2.427282930311.2.3321.2.433341.2.4.1351.2.4.236371.2.4.3381.2.4.4391.3401.3.11.3.1.1411.3.21.3.2.1421.3.2.21.3.2.3431.3.2.41.3.2.51.3.2.6441.3.31.3.3.1451.3.3.2461.41.4.11.4.24722.1472.1.1482.1.22.1.2.149502.1.2.22.2512.2.12.2.1.1522.2.1.253542.2.1.355565758596061622.2.263642.2.32.2.3.1652.2.3.2662.2.3.3672.2.468692.2.4.1707133.1723.1.13.1.27374753.23.2.1763.2.1.1777879803.2.1.23.2.281823.33.3.1833.3.2848586878889903.3.3919244.14.1.192934.1.24.1.2.194954.1.2.2964.1.2.34.1.2.4974.1.2.5984.1.2.64.1.2.7994.24.2.11001014.2.24.2.2.11024.2.2.21034.2.2.34.2.2.3.11044.2.2.3.21051061071084.31094.4110511011111261126.11136.26.31147. ReferencesAnnex 1Annex 2AcknowledgementsPublicationsCurriculum vitaeEIDESSTATTLICHE ERKLÄRUNGdeInhaltsverzeichnisHilfe Future works

The tissue differentiation model developed allows deeper insight into further subjects related to osteochondral healing. Various interesting applications of this technique may be analyzed in the future. Some possibilities for further research are briefly discussed below.

Future works related to the usage of the tissue differentiation model

  1. The tissue differentiation model could be used to determine the load condition that permits the largest formation of hyaline cartilage. A sensitive analysis could then be performed in which the design variable is the load and the other parameters should remain unchanged.

  2. In this project two different stiffness conditions of a defect filling were analyzed: A plug with 100% of the native subchondral bone stiffness and another with 50% of the native subchondral bone stiffness. The differentiation model could be used to determine an inhomogeneous stiffness of the defect filling so that different elastic modulus for the plug material properties could be suggested to construct such an implant.

  3. The plug geometry could be analyzed to reduce stress concentrations. The use of a plug with rounded borders at the basis could be necessary. Consequently, before the implant can be used it may be recommendable to smooth the defect geometry to achieve the same plug geometry. The differentiation model could show the effect of an optimized assembly interface defect-plug on osteochondral healing.

  4. Patient data could be used to construct the geometry and density distribution of the joint region in order to analyze the more favorable healing prediction from the tissue differentiation model after simulation of different treatments.

Future works related to the algorithm

Permeability is a material property related to the fluid mechanics behavior of a biphasic-modeled tissue. In the algorithm permeability is updated in dependence on the current material property. It is recommendable to change the permeability dependence so that this parameter may be updated in relation to the current strain values.

Future works related with the finite element model

  1. In the finite element model, the defect size is very large compared with the joint size. Perhaps the influence of the boundary conditions on the remaining tissues is overestimated. Modeling a large joint region could produce a reduction of the “zone of influence” observed at the cancellous bone subjacent to the osteochondral defect. Although this reduction is actually only 15% of the initial subchondral bone stiffness and then incrementally reestablished to the original value, the zone of influence achieves the upper model frontier.

  1. Since the analysis of joint curvature shows an influence of the stiffness of the remaining subchondral bone on the quantity and quality of the newly formed hyaline cartilage, it may be necessary to conduct a more detailed analysis of this region. The reconstruction of a system of the trabecular geometry of the subchondral bone region considering density distribution is recommended. The differentiation model should be able to show how this trabecular system is affected and how it influences the cartilage formation. Perhaps it could be demonstrated that a subchondral bone with poor bone quality decreases the percentage of hyaline cartilage formation.