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Biomedical subjects

H Cotta

Publications and source records attributed to H Cotta.

At least 19 recordsLinked to original sources
PubMed1997

Quantitative assessment of callus distraction using dual energy X-ray absorptiometry.

Bone mineralisation during and after limb lengthening procedures on the femur or tibia using unilateral fixators has been monitored quantitatively using dual energy X-ray absorptiometry (DEXA). We measured the bone mineral density (BMD) prospectively in the newly formed callus, in the bone adjacent to the callus and in the proximal femur. In twenty-one patients we showed a typical course with a peak value at 4-6 weeks after beginning distraction and a minimum value at maximum distraction. In the consolidation period the BMD in the distraction gap increased until the fixator was removed. The BMD in the regenerated bone increased faster in the regions of interest (ROI) opposite the fixator compared to those near it. Dynamisation caused more homogeneous regeneration equalising VBMD in the different ROIs. The BMD in the proximal femur of the leg which was operated on decreased to 67% and in the opposite leg to 87% of the preoperative value. DEXA provides a precise and quantitative assessment of callus and bone mineralisation during limb lengthening and helps in understanding what is happening during these procedures.

Absorptiometry, Photon↗
PubMed1995

Fractioned drilling--a technique for wedge osteotomy of the knee.

High tibial wedge osteotomies are often followed by transient neurological complications. From a retrospective study of 132 patients it appears that the incidence of this troublesome complication can be reduced after osteotomy with external fixation by using a technique of making consecutive drill holes of increasing diameter followed by osteoclasis. This reduction of neurological complications was most marked when a less extensive surgical approach was used.

Adult↗
PubMed1995

[Results of treatment after traumatic shoulder dislocation. Thoracic abduction plaster case or Desault dressing].

In 80 patients with primary traumatic shoulder dislocation treated at the Heidelberg Orthopaedic University Hospital we had a follow-up examination. We wanted to know about age and sex of the patients, the number of redislocations in correlation to time and way of fixation. We had 70% male and 30% female patients with 97.5% of anterior dislocation. The minimum age was 16 and the maximum 87 years with an average of 44 years. 48 patients had a Desault bandage for 2 weeks and 32 had a shoulder-arm plaster cast for 3 weeks. There was no difference between both ways of fixation. We also could not see any better results after more than a 3 weeks' fixation. The most important fact for redislocation is the age and activity of the patients. A young man has a very high risk of redislocation within the first year.

Adolescent↗
PubMed1995

[Quantitative follow-up of callus distraction with dual-energy roentgen absorptiometry (DEXA)].

With dual-energy X-ray absorptiometry (DEXA), bone mineralization during and after limb-lengthening procedures with unilateral fixators can be monitored quantitatively and precisely with low radiation exposure. We measured prospectively the bone mineral density (BMD) in the newly formed callus, in the bone adjacent to the callus and in the proximal femur in 21 patients with leg lengthening of the femur and/or tibia with unilateral external fixators. Mineralization showed a typical course with a peak value of 0.365 +/- 0.196 g/cm2 (30.9% of the first value) at 6-8 weeks after the beginning of distraction and a minimum value at the time of maximum distraction. In the consolidation period BMD in the distraction gap increased to 1.020 +/- 0.234 g/cm2 (87%) at the time of fixation removal. BMD in the regenerated bone increased faster in regions of interest (ROIs) opposite the fixator compared to ROIs near it. Dynamization of the fixation device led to a 13% increase in mineralization velocity (VBMD). On the other hand, dynamization caused more homogeneous regeneration equalizing VBMD in the different ROIs as well. BMD in the proximal femur of the leg operated on decreased to 67% and in the contralateral leg to 87% of the preoperative value. We consider DEXA to provide a precise and quantitative assessment of callus and bone mineralization during limb lengthening with unilateral fixators. Since we are well aware of the limitation of the technique. DEXA helps to understand what is happening in limb-lengthening procedures by providing quantitative values.

Absorptiometry, Photon↗
PubMed1994

[Clinical and radiological results with the spherical Mecring as acetabulum prosthesis in hip joint diseases].

The recent experiences which the university hospital in Heidelberg has made with the spherical Mecring must be valued positively. Clinical, radiological and subjective dates from 147 patients were worked up retrospectively. Indeed, the positive results must be considered as relative because of the short respectively medium-term period of control. Nevertheless, the repeated improvement in the second group after a period of postexamination on a average of 3.05 years lets hope for positive long-term results. In the period between 1985 and 1990 three sockets had to be changed. The reasons that the sockets loosened were not specific for the screwing but depending on the individual patients or on the implantations and technical circumstances. The negative results achieved by Engh et al. 1990 could not be recognized (8). He measured a radiological instability of 18% and a technical instability of 28%. What Engh did was measuring simple review photographs and extracting valuable material from them while using geometrical methods. This method shows various measuring mistakes. Therefore Engh's conclusion that the screwing should not be used for implantation because of its displacement in the bones is doubtful. The doubts seem to be supported by the results of our comparison of two series of X-ray photographs with defined different pelvis positions of the same patient. The screwing seemed to be significantly displaced in cranio-medial direction. This was proved by experimental photographs with a pelvis raised to 6 cm in contralateral direction. But the results were a matter of radiological illusion. Radiological migration of the screwing is only provable by complicated X-ray analyses steered with the computer. These big X-ray series are not accessible at the time.

Acetabulum↗
PubMed1994

[Characteristics of chondromyxoid fibroma: are malignant courses possible? Presentation of personal cases and review of the literature].

The chondromyxoid fibroma as a benign bone tumour is described. The difficult but extremely important differential diagnosis from chondrosarcoma is discussed, and the question of the existence of malignant chondromyxoid fibroma is examined. Cases of malignant chondromyxoid fibroma that have been reported in the literature are described and critically analysed. Experience with seven chondromyxoid fibromas and two tumours misdiagnosed as malignant chondromyxoid fibromas are described. In view of the clear definition of chondromyxoid fibroma and chondrosarcoma the term malignant chondromyxoid fibroma is not justified and should no longer be used.

Adolescent↗
PubMed1991

[Malunited juvenile fractures in the knee joint region].

There is a tendency for malunion to occur in fractures of the knee region in children because the growth plates are often affected. Leg length discrepancies are reported in more than 50% of the children and axis deviations in 20-40%. The prognostic significance of epiphyseal lesions is described (not always accurately) by the classifications of Salter and Harris or Aitken. Treatment is mostly directed at leg-length discrepancies and axis deviations by resection of callus formations, epiphysiodeses and osteotomies. A complete bone growth history is necessary to plan the operative procedure.

Adolescent↗
PubMed1989

[Instability of the wrist joint--diagnosis and therapy].

Wrist-joint instability can be caused by injuries to ligaments or bones, it can be intermittent or permanent. Clinical symptoms and pain sensations are non-characteristic. The X-ray findings are the clue to the diagnosis. In this article recommendations are given for exact X-ray positions of the hand and their evaluation. The classification of instability is corresponding to the X-ray findings. Further investigations like radiographs under stress, dynamic investigations or the arthrography of the wrist-joint can be helpful to find out the exact pathologic changes. They are variable and are ranging from dysharmonic movement to a complete destruction of the carpal bones. Treatment is according to the pathologic changes and their causes. Fresh ligamentous injuries (e.g. additional injuries to a Colles' fracture or a perilunate luxation) should not be discarded lightly. Most cases we saw presented very late, the patients showed already osteoarthritic changes of the carpal bones with destruction of the cartilage. The late results of ligamentous reconstructions have not fulfilled their expectations, the current trend is towards a partial arthrodesis of the carpal joints in order to reconstruct the joint stability under preservation of partial mobility. This method of treatment has certain disadvantages: Pathologic wrist-joint movements, impingement syndromes and undue stress reactions within the neighbouring joints. Recommendations for the different indications are given.

Arthrodesis↗
PubMed1989

[Subcutaneous muscle and tendon ruptures].

Reasons for subcutaneous ruptures of muscles and tendons are discussed from biomechanical and kinesiological points of view Experimental findings and clinical diagnostic procedures applied in muscle and tendon rupture are discussed. It is concluded that the aim of repair in the case of either muscle or tendon must be the reconstruction of their physiological length in order to avoid loss of muscle strength, which would increase the frequency of muscle and tendon injuries and cause a decline in sports performance. Therefore, surgical repair of complete muscle and tendon rupture has to be regarded as the therapy of choice especially in young patients and those engaged in competitive sport. It must be taken into account, however, that both surgical and non-surgical repair lead to the same weight-bearing capacity. Therefore, functional, non-surgical treatment must be preferred in the case of partial muscle and/or tendon rupture and in older patients.

Athletic Injuries↗
PubMed1989

[Structure and function of the "neosynovial membrane." Light and transmission electron microscopy studies of regenerated synovial membranes following surgical synovectomy].

Regenerating synovium from seven patients was examined by light- and transmission electron microscopy. Superficial layers of the "neosynovium" are composed of histocytes, fibroblasts and intermedium cells, developing out of undifferentiated mesenchymal perivascular connective tissue cells. There is no closed cell-layer, as known from mesothelia, endothelia and epithelia. Our results are similar to those of normal synovium and the so-called "pseudo-synovium" of pseudarthroses. So superficial layers of these tissues are comparable specialized connective tissues. According to experimental results in animals, in patients there will develop a "neosynovium" comparable to the original synovium in structure and function. These results confirm synovectomy as a possible operative treatment in patients.

Arthritis, Rheumatoid↗
PubMed1988

[The femoro-patellar joint and cartilage damage of the knee joint].

This article surveys the update knowledge of diagnosis and treatment of damage to the cartilage with particular reference to the femoropatellar joint. Complementary to this the biomechanical fundamentals and special anatomic features are explained, the knowledge of which is imperative for an understanding of the complex linkups and interconnections.

Arthroscopy↗
PubMed1986

[Alternatives to endoprostheses of the hip and knee joint].

Total hip and knee replacement is one of the most successful operative procedures in orthopaedic surgery. With respect to greater life expectancy, however, loosening of the implant and revision surgery with all its sequelae must be taken into account. Therefore joint preserving procedures resp. arthrodesis of the hip and knee joint are still of great importance. The best long term results can be achieved by operations which can improve the biomechanics of the joint. Operative procedures which aim at the biology of the joint only lead to temporary pain relief. Arthrodesis of the hip and knee joint should always be considered in young patients with no possibility for joint preserving techniques.

Arthrodesis↗
PubMed1984

[Pathological fracture of the proximal femur and its therapy].

"Pathologic fracture" is understood as a discontinuity of pathologic bone caused by normal mechanical stress without adequate trauma. The pathologic condition of bone causing mechanical instability may be a general osteopathia (osteoporosis, osteomalacia, fibrous dysplasia, Paget's disease) or as well a localized one (primary or secondary bone tumors, tumor-like lesions, osteomyelitis). Following "pathologic fracture" pain and functional deficiency are severe, so besides diagnosis and treatment of basic disease conservative and often operative treatment of the pathologic fracture are necessary. The different procedures are discussed in relation localisation of pathologic fracture, basic disease and age of patient.

Adult↗
PubMed1983

[Backache and low back pain. Diagnosis and treatment].

In patients with back pain there is only a poor correlation between clinical and radiological symptoms. Therefore the interpretation of radiological findings is only possible with respect to the natural history of the disease. Indication for radiological examination is given for early diagnosis and treatment of malformation of the spine; diagnosis and treatment of functional disturbances of the spine with back- and low back pain and diagnosis and treatment of diseases which affect the stability of the vertebrae.

Adolescent↗
PubMed1982

[Consequences of hemarthrosis for the knee joint (author's transl)].

The presence of an hemarthrosis generally is a sign of a particularly severe joint lesion. Arthrous alterations appearing post-traumatically can therefore be due to the extent of the joint lesion as well as to the accompanying hemarthrosis. A group of 24 young adult rabbits was submitted to morphologic examinations in order to find out in which way an isolated hemarthrosis can be responsible of degenerative cartilage alterations. At intervals of eight days each, 3 cm3 of their own blood were injected into both knee joints of the rabbits. One knee joint was immobilized, the other was mobile. The results prove that the hemarthrosis represents a considerable risk with regard to the trophism of the concerned joint. A direct enzymatic damage to the joint cartilage alone or in combination with trophical alterations appearing later on can lead to a formation and aggravation of arthrosis. The degenerative alterations are increased in an immobilized joint. Bearing in mind these alterations, the conclusion is drawn for clinical practice that the hemarthrosis has to be considered when establishing both diagnosis and therapy plan (punction, joint lavage, drainage, immobilization as early as possible).

Animals↗