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Biomedical subjects

E J Henssge

Publications and source records attributed to E J Henssge.

8 recordsLinked to original sources
PubMedDate not supplied

[Reactions of the osseous site following implantation of cemented endoprostheses in the femur].

17 autopsy femora with fixed cemented endoprostheses were sectioned horizontally and studied histologically, morphometrically and microradiographically. The implantation period varied between 0 and 12 years. It was frequently found that in distal segments the implant was already loosened shortly after implantation. The morphometrical analyses showed no significant bone changes distal to the trochanter minor. Enhanced microresorption and areas of reduced mineralization were found at the cement-bone interface. The total bone alterations, however, are not very extensive and seem not to be responsible for aseptic loosening, but the frequently inferior fixation instead.

Aged↗
PubMedDate not supplied

[Differences in polyethylene wear in hip joint prostheses with ceramic- and with metal-polyethylene combination of the articulation surfaces--a study of surgical and of autopsy materials].

Pseudocapsules of artificial hip joints with ceramic- and metal on polyethylene combination of the articulating surfaces from 126 revision arthroplasties and 41 autopsies were studied histologically with semiquantitative evaluation of the polyethylene wear. The results were compared with reports of laboratory tests in the literature. We found in the autopsy specimens as well as in the biopsies from revision arthroplasties of prostheses implanted for 4 to 8 years three times less polyethylene wear particles released from the ceramic on polyethylene prostheses. The newly established synovium surrounding prostheses with ceramic heads appeared 20% reduced in thickness with minor villous transformation. Different types of metal on polyethylene prostheses revealed no differences in wear behaviour with the exception of the bipolar prostheses which showed a markedly increased polyethylene wear.

Adult↗
PubMedDate not supplied

[Anatomically adapted endoprosthesis of the proximal end of the femur].

The marrow-cavities of several human femora were cleaned and filled with plastics; the femoral component design was developed based on these moulds. Different sizes of the stem were obtained by scaling down the biggest mould in steps of 10%. The stem has an oval cross-section and is twisted similar to the form of the marrow-cavity; therefore different designs for the left and right femur are necessary. As the marrow-cavity of the femur tapers down to the middle of the shaft the length of the prosthetic stem cannot be selected arbitrarily. The stem must end above the narrowest site of the cavity. Data are presented. To avoid disadvantageous frictional stresses between the collar of the prosthesis and the plane of resection of the femoral neck both must be aligned perpendicular to the most common direction of the load of the hip joint. Therefore a step-like osteotomy of the femoral neck becomes necessary without disturbing the calcar femorale instead of an inclined osteotomy. A firm contact between the femoral wall and the collar, which forms an angle of 64 degrees with the axis of the femoral shaft, guarantees that only small frictional stresses occur between collar and femoral cortex if the load of the hip joint varies within the physiological range. A set of ceramic femoral heads with three different conical borings yield different lengths of the neck of the prosthesis. Independent of which femoral head and which size of prosthesis are chosen the direction of the maximum hip load in any case thrusts the contact area between collar and femoral wall. Thus dangerous tilting moments round the medial calcar femorale do not occur, the incidence of a fracture of the prosthesis shaft is therefore reduced. After implantation of the anatomically designed femoral component both remodeling and resorption of the calcar femorale are observed. This reaction is independent of the kind of fixation, i.e. if a smooth stem was fixed with cement or a stem with a porous, cancellous bone-like metallic surface was implanted without cement fixation.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMedDate not supplied

[Cast metal spongioid bone implants in animal experiments].

Spongyimplant cubes produced out of an alloying DIN 58800 are driven in an artificial produced split in the ileosacral articulation of sheeps. The animals were killed after a period of 70 til 181 days. All the implants are enclosed by bone and so bring about an ankylosis of the ileosacral articulation. In different degree the porous slices of the implant are grown through by bone. By producing spongyimplants with more porous slices the transfer of the animal experiment to human beings is justified, for example for special problems in osteosynthesis of in the arrange of the surface from artificial implants. The produced spongy implants out of metal are characterized specially by its primary stability.

Alloys↗
PubMedDate not supplied

[113 Re-operations to correct loosening of prosthesis shafts - personal experiences and conclusions (author's transl)].

one hundred and thirteen re-operations necessitated by loosening of the prosthesis shaft were analyzed with regard to surgical stress, technique and results. Of these operations to replace the prosthesis shaft, the surgical technique employed depended on the individual situation in 94 cases. In some, the implant and cement cone were removed, in some the medullary space was foragad, and in others single or multiple fenestration was performed. The surgical investment in these 94 operations proved to be especially high. The main disadvantage of individually oriented, partly improvised procedures is that granular tissue remains in the former contact zone between cement cone and bone. Uncovering of the shaft of the femur in a planned procedure employing the fenestration/chiseling method (19 patients) represents a way of cleaning the medullary cavity completely prior to fitting the replacement implant, with a low level of surgical stress. Implants whose shape corresponds as closely of the shaft are preferred to the so-called long-shaft implants. The authors see a considerable improvement in the departure from individually oriented and partially improvised procedures in replacement interventions: the surgical stress imposed by the operation is easier to assess and the safety of the implant renders the chances of success greater.

Femoral Fractures↗