[Macroscopic and microscopic anatomy of the shoulder joint and the limbus glenoidalis]. / Zur makroskopischen und mikroskopischen Anatomie der Schultergelenkspfanne und des Limbus glenoidalis.

Macroscopical and histological examinations were carried out in order to investigate the anatomy of the limbus glenoidalis, with respect to its surrounding structures such as tendons and ligaments. Basically the crosscut limbus glenoidalis has a triangular shape, however, especially in its anterior part, it has a meniscoid or labiate form. Histologically the limbus glenoidalis consists exclusively of connective tissue, rich in cells and fibers. It originates from the fibrocartilaginous rim of the glenoid surface, which merges into the hyalin cartilage. The bundles of fibers have a circular arrangement with radially and reticularly interwoven structures near the tendons of the biceps and triceps muscle.

Guidelines for Chiari's osteotomy in the immature skeleton developed from a canine model.

Three variations of Chiari's pelvic osteotomy were performed on 18 dysplastic hip joints in young, growing German shepherd dogs and rottweilers. The results of the operations and the reactions of the skeletal tissue were investigated radiologically and histologically after six and 12 months. By use of polyfluorochrome sequential labeling and microangiography, it was demonstrated that neither the formation of new bone nor the blood supply in the vicinity of the rim of the acetabulum (apophysis of the acetabular roof) was seriously impaired by the operation. Conversely, the operative technique was of decisive importance to the result of the operation. Only if the osteotomy was performed through the original acetabular rim, completely covering the femoral head, was the newly formed acetabular roof adequately biomechanically loaded, providing the conditions required for functionally adapted differentiation of skeletal tissue. Chiari's pelvic osteotomy can be performed on canine hips with good chances of success, provided one uses the proper operative technique. Apophyseal bone growth and the blood supply of the newly formed acetabular roof were apparently not disturbed by Chiari's operation.

The interposition of Lyodura in operations for ankylosis of the temporo-mandibular joint. An experimental study using pigs.

Experimental investigations using domestic pigs were carried out in order to study the subject of resorption of lyophilized Dura (Lyodura) interposed in the region of the temporo-mandibular joint after operations for ankylosis. The condyle of the mandible was partially resected on one or both sides, the joint capsule and disc excised and the mandibular fossa stripped of cartilage. Lyodura was interposed between the surfaces of the bones and intravital sequential labelling of the bones was carried out using fluorochromes. The animals were sacrificed after 18, 36, 50 and 120-130 days and the joint region excised. Undecalcified microtome (5-8 mu) and ground sections were prepared and contact microradiographs made. It was found that the Lyodura remained in place in spite of the mechanical loading until it was assimilated by a foreign body reaction and replaced by largely collagenous, endogenous connective tissue. Spaces similar to the joint cavity and lined with pseudosynovia were found after 120-130 days.

Experimental investigations into the clinical significance of bone growth at viscerocranial sutures.

The development of a viscerocranial suture under physiological conditions was investigated in a total of 37 pigs and the effects of various traumas on expected sutural bone growth were observed. Different operations were carried out on one side only in the vicinity of the zygomaticotemporal suture in 18-25 day old piglets. The animals were sacrificed six months after the operation. The skulls of some of the animals were macerated and subjected to macroscopic and radiological investigation. Both zygomatic arches were removed from each of the remaining animals and used for the production of undecalcified microtome and ground sections. Intravital fluorochrome labelling was used to determine the asymmetric growth at this suture; this is interpreted as being the formation of new bone following passive expansion of the sutural region. After injury or transplantation of the periosteum and after the healing of a narrow bone defect or fracture we observed either a continuous suture from the outset or the formation of a new fissure after osseous regeneration. Similar findings were also made after the transplantation of compact rib fragments into a sutural defect without subsequent bridging of the defect. Only after the transplantation of autologous pieces of cancellous rib into an osseous defect in the sutural region was sutural ossification, accompanied by distinct deformation of the skull observed. As a clinical consequence of this it may be presumed that trauma or operation in the region of a suture has a considerable effect on the growth of the visceral cranium only if it results in premature synostosis.

Experience with bioceramic implants in orthopaedic surgery.

In the period from 1974 to March 1980 bioceramic endoprostheses were implanted in 155 patients. 94 patients were suffering from degenerative hip diseases and 61 had been operated for malignant bone tumours. The majority of the total endoprostheses consisted of a ceramic socket and a metal shaft prosthesis with ceramic head attached to it. Bioceramic double-cup prostheses were implanted in 19 patients without using bone cement. Following resection of malignant bone tumours, the proximal humerus and the proximal femur were replaced by special bioceramic endoprostheses. The post-operation period after implantation has reached 70 months in the case of tumour endoprostheses (average 22 months) and up to 49 months in the case of hip joint endoprostheses (average 24 months). The analysis deals exclusively with complications specific to the ceramic material. These complications are: breakage of the ceramic head (8 X), loosening of the ceramic cup (13 X) and pseudarthrosis of the cone connection in tumour endoprostheses (9 X). Abrasion particles were found in all cases which we were able to follow up histologically.

[Experimental investigations on the growth of the vertebral column after dorsal spondylodesis (author's transl)]. / Experimentelle Untersuchungen über das Wachstum der Wirbelsäule nach dorsaler Spondylodese.

To investigate the question which growth processes take place in dorsally stiffened vertebral regions, 4 vertebral segments each were dorsally fused in twenty-one pigs, using Harrington's distraction system in 20 cases. X-ray examination and histological measurements conducted with the aid of fluorochromosequential markings showed a more or less pronounced growth of the vertebral bodies and of the fusion mass in all animals. As a rule, the sequence of vertebral bodies overgrows the fusion mass in longitudinal direction, which always results in lordosis of the stiffened region. The longitudinal growth of the vertebral bodies, and even more so of the fusion mass, decreases with increasing postoperative observation time. The fusion mass shows actual internal growth which proceeds partly in diffuse manner in all directions, in the region of the clefts, i.e. as spondyloschisis, in some cases also in the same direction as with enchondral ossification associated with columnar chondrification. The growth of the fused mass does not depend on the formation of a pseudoarthrosis, although it is probably quantitatively promoted by pseudarthroses. The stimulus to longitudinal growth of the fused mass originates from the growing vertebral bodies, with probably varying influence of tensile and compressive forces.

[Investigation of bone growth into porous metal implants (author's transl)]. / Untersuchungen über das Einwachsen von Konchengewebe in poröse Metallimplantate.

Stainless-steel cylinders of different pore size were implanted into the tibia, and small tubes, 500 micrometers diameter, of the same material into the iliac crests of 19 rabbits. It was found that after three weeks ingrowing bone tissue anchored the cylinders if the pore size was adequate. The same applied to the tubes. A stable implantation was the prerequisite for the ingrowth of fibre-bone trabeculae. Additionally, the use of fibrinogen adhesive system seems to be advantageous for this anchorage. These results were established by mechanical tensile tests and morphological examinations.