[The relevance of the sagittal profile in cervical artificial discs]. / Die Bedeutung des sagittalen Profils bei der zervikalen Endoprothetik.

We report on the results of 246 Bryan cervical discs, which were implanted between June 2002 and September 2010 in 146 patients. Of the patients 74 (128 prostheses) could be followed up for more than 1 year and the average follow-up period was 2.6 years. Of the patients 18 were operated on at one level (group 1), 77 prostheses were multilevel surgery (group 2) and with 33 patients arthroplasty was combined with fusion (hybrid, group 3). The global lordosis remained unchanged during follow-up and a recurrence of kyphosis was evident in group 3. The overall mobility improved in all 3 subgroups and 2 cases (group 3) fused. With 5 patients the prosthesis had to be removed and the segment had to be fused in the postoperative course. As a conclusion a meticulous preoperative planning as well as a subtle surgical technique is the main prerequisite for long-lasting mobility of the Bryan prosthesis.

Nano-material aspects of shock absorption in bone joints.

This theoretical study is based on a nano-technological evaluation of the effect of pressure on the composite bone fine structure. It turned out, that the well known macroscopic mechano-elastic performance of bones in combination with muscles and tendons is just one functional aspect which is critically supported by additional micro- and nano- shock damping technology aimed at minimising local bone material damage within the joints and supporting spongy bone material. The identified mechanisms comprise essentially three phenomena localised within the three-dimensional spongy structure with channels and so called perforated flexible tensulae membranes of different dimensions intersecting and linking them. Kinetic energy of a mechanical shock may be dissipated within the solid-liquid composite bone structure into heat via the generation of quasi-chaotic hydromechanic micro-turbulence. It may generate electro-kinetic energy in terms of electric currents and potentials. And the resulting specific structural and surface electrochemical changes may induce the compressible intra-osseal liquid to build up pressure dependent free chemical energy. Innovative bone joint prostheses will have to consider and to be adapted to the nano-material aspects of shock absorption in the operated bones.

[CCL-tensulae in the skeleton as part of a hydrodynamic skeletal system]. / Die CCL-Tensula im Skelettsystem als möglicher Teil eines hydrodynamisch wirkenden Faktors.

Previous morphological studies on human bone have demonstrated that veil-like structures ('tensulae') occur in highly stressed regions, i.e. the interface between cartilage and bone. In the present report we describe the distribution of tensulae within various types of human bone by means of scanning electron microscopy and light microscopy. Tensulae were predominately located within bone tissue adjacent to mineralized cartilage. The surface diameter of tensulae ranged from minimal 50 to maximal 400 microns. Occasionally, collagen fibers extended from the interface between cartilage and bone to tensulae. Frequently, the latter were attached to fat cells as well as bone marrow cells. An elemental analysis of tensula revealed high levels of calcium and phosphorus of equal concentrations. However, bone tissue contained higher levels of calcium compared to phosphorus. Additionally, a monoclonal antibody was generated by immunizing rats with bone marrow of mice. Within bone tissue this monoclonal antibody selectively stained membrane-like structures which were clearly identified as tensulae. From our investigations we conclude that the function of tensulae in bone may be to absorb stress in regions where large forces are applied.

[Detection of hydrodynamically operative tissue in the substantia spongiosa of the femoral head in Bos taurus and Ovis aries]. / Nachweis der hydrodynamisch wirkenden Tensulae in der Substantia spongiosa des Caput femoris bei Bos taurus und Ovis aries.

The authors show the presence of CC-Tensulae in Bos taurus and Ovis aries. They define CC-Tensulae as tense membranes in openings between the trabeculae of spongy bone. These structures were interpreted in man as a hydrodynamic subsystem which serves the flow and the impulses of mechanical forces. The authors point especially to the similarity that exists between their findings and what has been seen in man.

[Ultrastructure of the substantia spongiosa of the femur head and talus]. / Substrukturen in der Substantia spongiosa des Caput femoris und des Talus.

The results of the SEM examination of the zone between the cartilage and the spongeous substances are described precisely. For the first time, W. Lierse examined the 'tensulae' of calcium-collagen lamellae by light microscopy. The examination of this zone was initiated by the fact that the hydrodynamic flow can take place in the calcified zone of the cartilage which is filled with synovial fluid and that the calcified zone adheres to the subchondral substantia corticalis. The subchondral corticalis is characterized by funnel-like indentations with a high number of calcium-collagen and chondrocyte 'tensulae' which are up to now uncounted. The special aim was to locate the separation of the space of adipose and arterial supplies.

[The hydrodynamic components in joints: proof of a membrane-cistern system within the calcified zone of the femur head cartilage]. / Die hydrodynamische Komponente im Gelenk: Nachweis eines Membranen-Zisternen-Systems in der kalzifizierten Zone des Knorpels am Femurkopf.

The theoretical postulate of a hydrodynamic system for the transmission of forces at the hip joint led to the discovery of a two-membrane system. Within the calcified cartilaginous zone of the femoral head there exists a system of small spaces and cisterns which can only be understood in the postulated sense as an overall acting hydrodynamic system. A correlation between the destruction of the calcified zone, i.e. the hydrodynamic system, and arthrosis is indicated. Ongoing studies and deliberations will help to discover the true model of the transmission of forces and impulses and to solve the problems of treating arthrosis.

[A biomechanical solution for permanent anchoring of artificial hip joint acetabula]. / Eine biomechanische Lösung zur dauerhaften Verankerung künstlicher Hüftgelenkspfannen.

This paper describes models of artificial acetabula which are better adapted to the structural conditions of the fixation bed than the prostheses used hitherto. The most important design feature is the increased area of surface contact between the artificial acetabulum and bone by means of stepped anchoring pins, which extend radially into the spongiosa from the surface of the acetabulum. The location and length of these small anchoring pins depends on the bone architecture of the acetabulum.

[Biomechanical problems in elbow joint dislocations with coronoid and capitulum radii fractures (author's transl)]. / Biomechanische Probleme bei Ellenbogenluxationen mit Frakturen am Processus coronoideus und Radiusköpfchen.

Dorsal dislocation occurs in 80% of all fracture dislocations of the elbow joint. In 10-15% of these njuries the coronoid process and the radial head are involved. If this injury causes the defect of the radial head - which means the loss of the main supporting part of the joint, - it is only the coronoid process which gives stability to the elbow joint. Therefore, in cases of coronoid fracture it is of utmost importance to reconstruct the coronoid process, if the fracture involves more than 1/6 of the incisura olecrani. Advisable for fixation is the use of a lag screw. In some cases the reconstruction with autogenous bone graft or osteotomy of the olecranon is indicated.