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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Archives of orthopaedic and trauma surgery 116 (1997), S. 137-142 
    ISSN: 1434-3916
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The mechanical performance and the stress shielding effects of the Howmedica Spherolock MKII implant were evaluated. Three types of stable proximal femoral fractures were created in composite femurs and fixed with the nail-plate. The femurs were loaded to failure, and the yield strength, stiffness, and failure modes were noted. Additional intact composite femurs were fitted proximally with strain gauges, and the strain was examined under load. The femurs then underwent intertrochanteric fracture, plating, and re-testing. Comparative analysis showed that while the Spherolock system is less strong and stiff than other commonly used implants, it provides excellent and uniform load transfer across the fracture site. Varus rotation of the femoral head under load tended to open the fracture gap and localize the resultant load medially. Stress shielding of the calcar was less than 25% of the applied load even in the worst case. This very low stress shielding behavior was attributed mainly to the implant’s low stiffness.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Archives of orthopaedic and trauma surgery 116 (1997), S. 137-142 
    ISSN: 1434-3916
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The mechanical performance and the stress shielding effects of the Howmedica Spherolock MKII implant were evaluated. Three types of stable proximal femoral fractures were created in composite femurs and fixed with the nail-plate. The femurs were loaded to failure, and the yield strength, stiffness, and failure modes were noted. Additional intact composite femurs were fitted proximally with strain gauges, and the strain was examined under load. The femurs then underwent intertrochanteric fracture, plating, and re-testing. Comparative analysis showed that while the Spherolock system is less strong and stiff than other commonly used implants, it provides excellent and uniform load transfer across the fracture site. Varus rotation of the femoral head under load tended to open the fracture gap and localize the resultant load medially. Stress shielding of the calcar was less than 25% of the applied load even in the worst case. This very low stress shielding behavior was attributed mainly to the implant's low stiffness.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Skeletal radiology 13 (1985), S. 21-25 
    ISSN: 1432-2161
    Keywords: Bone tumours, benign ; Aneurysmal bone cyst ; Growth plate ; Epiphyseal invasion
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Nine cases of aneurysmal bone cyst arising in juxtaepiphyseal locations with gross invasion of the adjacent growth plate are reported. In five of these patients an abnormality of growth, due to premature fusion of the affected growth plate, ultimately developed. Treatment of these lesions should attempt to avoid this complication, which appears to be more common than has been appeaciated in the past. These nine cases represent 23% of 39 cases of aneurysmal bone cyst occurring in a long bone adjacent to an open epiphyseal plate. This series was extrapolated from a total of 198 cases of aneurysmal bone cyst in the files of the Istituto Ortopedico Rizzoli, Bologna, Italy.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1432-0932
    Keywords: Lésions du rachis cervical inférieur ; Décompression antérieure ; Ostéosynthèse par plaque vissée ; Lower cervical spine injuries ; Anterior decompression ; Plate fixation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Summary Surgical treatment of unstable traumatic injuries of the cervical spine can be carried out by a posterior or anterior approach, with different advantages and disadvantages. Twenty patients were treated with anterior decompression, interbody fusion with autogenous iliac bone graft, and osteosynthesis with a Louis anterior plate. The screws were inserted in the vertebral body without reaching the posterior vertebral wall. There were 18 male and 2 female patients, aged between 18 and 66 years (average 36 years). The osteoarticular lesion was in 8 cases a tear-drop fracture and in 12 a fracture-dislocation. The mechanisms of injury were flexion-compression, flexion-rotation, hyperflexion, and hyperextension. A complete spinal cord lesion was present in 10 cases, central cord syndrome in 5, isolated radiculopathy in 3, and anterior cord syndrome in 1; one patient had normal neurological function. At long-term follow-up fusion of the graft was observed in all cases without evidence of spinal malalignment, breakage of the implant, or aseptic hardware loosening. Neurological deterioration was not observed in any case. In one case, complicated by late infection, healing was uneventful after plate removal, surgical debridement, and antibiotic therapy. A fistula of the hypopharynx due to perforation of the piriform recess appeared following repeated bronchoscopy 12 months after surgery. There were no signs of implant loosening and the lesion was surgically repaired. From a neurological point of view the 10 patients with complete cord lesion remained unchanged; those with incomplete cord lesions improved by 1 or 2 degrees on the Frankel scale; those with isolated radiculopathies recovered fully; and the neurologically intact patient remained unchanged. The present study and the data reported in the literature prove that anterior surgery with plate fixation in cervical spine injuries allows the achievement of complete neural decompression by direct visual examination. On the other hand, posterior surgery can result in incomplete decompression and associated neurological deterioration. Anterior plate instrumentation has proved itself mechanically adequate, even if it is less stable than posterior constructs. The advantages of anterior surgery compared to those of posterior surgery are such that several specific risks are acceptable. Posterior surgery is nevertheless indicated if the lesion cannot be reduced preoperatively under closed conditions.
    Notes: Résumé Le traitement chirurgical des lésions traumatiques instables du rachis cervical peut être réalisé par un abord postérieur ou antérieur, avec des avantages et des inconvénients différents. Vingt patients ont été traités par décompression antérieure et arthrodèse intersomatique associant une greffe autogène d'os iliaque et une ostéosynthèse par plaque antérieure de Louis. Les vis ont été implantées dans le corps vertébral sans atteindre le mur vertébral postérieur. La série comportait 18 hommes et 2 femmes, agés de 18 à 66 ans (âge moyen=36 ans). La lésion ostéoarticulaire était dans 8 cas une fracture en tear-drop, et dans 12 cas une fracture-dislocation. Le mécanisme lésionnel était soit la flexion-compression, soit la flexion-rotation, soit l'hyperflexion, soit encore l'hyperextension. Une lésion médullaire complète a été retrouvée dans 10 cas, un syndrome central de la moelle dans 5 cas, une atteinte radiculaire isolée dans 3 cas, un syndrome médullaire antérieur dans 1 cas, et une fonction neurologique normale dans un seul cas. Dans les suites lointaines, la fusion de la greffe a été observée dans tous les cas, sans désaxation rachidienne apparente, ni rupture de l'implant, ni démontage aseptique du matériel. L'aggravation neurologique n'a jamais été observée. Un cas, compliqué d'une infection tardive a guéri sans problème après ablation de la plaque, mise à plat et antibiothérapie. Une fistule de l'hypopharynx due à une perforation du sinus piriforme est apparue à la suite de bronchoscopies répétées 12 mois après l'intervention. II n'y avait aucun signe de démontage de l'implant et la lésion était consolidée. Du point de vue neurologique, les 10 patients présentant une lésion médullaire complète sont restés inchangés; ceux présentant des lésions médullaires incomplètes se sont améliorés de 1 à 2 degrés selon l'échelle de Frankel; ceux présentant une atteinte radiculaire isolée ont totalement récupéré et le patient neurologiquement intact est resté inchangé. Le présent travail et les données rapportées dans la littérature démontrent que dans les lésions du rachis cervical, la chirurgie antérieure associée à la fixation par plaque vissée, permet de réaliser une décompression neurologique complète grâce au contrôle visuel direct. D'un autre côté, la chirurgie postérieure peut n'obtenir qu'une décompression incomplète avec maintien de la détérioration neurologique qui s'y associe. L'instrumentation antérieure par plaque s'est montrée mécaniquement valable, même si elle est moins stable que les montages postérieurs. Les avantages de la chirurgie antérieure comparés à ceux de la chirurgie postérieure sont tels que les risques spécifiques sont acceptables. La chirurgie postérieure n'est indiquée que si la réduction orthopédique préopératoire ne peut pas être réalisée.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Archives of orthopaedic and trauma surgery 107 (1988), S. 186-188 
    ISSN: 1434-3916
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Es wird über den Fall eines tiefen Infektes mit Mycobacterium tuberculosis 2 Jahre nach künstlichem Hüftgelenkersatz berichtet. Bei dem 61-jährigen Patienten war weder in der Vorgeschichte eine Tuberkulose bekannt noch ließen sich zum Zeitpunkt der Endoprothesen-Implantation Zeichen einer systemischen Erkrankung feststellen. Es werden die klinischen und pathogenetischen Folgerungen diskutiert.
    Notes: Summary One case of deep sepsis from Mycobacterium tuberculosis occurring two years after total hip replacement is reported. The patient had no history of previous tuberculous infection nor showed any sign of systemic disease at the time of surgery. The clinical and pathogenic implications are discussed.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Journal of materials science 7 (1996), S. 149-152 
    ISSN: 1573-4838
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine , Technology
    Notes: Bone remodelling of the proximal femur following total hip arthroplasty (THA) is related to stress deviation with respect to physiological condition. The clinical relevance of this process is much debated with respect to its role in THA failure. In the present study a group of 475 An.C.A. anatomic cementless stems implanted in our institution were assumed as clinical reference. Of them, 294 had a short stem and 181 had a long stem. Stress shielding was X-ray evaluated in each patient. The survivorship analysis of this study group (negative events = stress shielding) showed significantly (p〈0.05) lower survival rates at 25 months follow-up for patients with long-stem implants. A 3-D FEM model of the proximal femur was used to analyse the load transfer mechanism for the two types of stems in fully or proximally only bonding conditions. Little difference was predicted in the proximal stress magnitudes for the different stem lengths. On the contrary, stem-bone bonding leads to a notable increase in the stress shielding.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 30 (1996), S. 181-186 
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: An accelerated cyclic loading corrosion test was used to determine the corrosion behavior of a commercial (GSP) and a prototype titanium hip prosthesis each with a modular neck. Four GSP and four prototype stems were subjected to a 2-Hz cyclic load ranging between 200 and 2,100 N for 1,000,000 cycles. Three stems were tested in an environment of FeCl3 solution, three stems were tested in Ringer's solution, and two stems were tested in air. After cyclic loading, the specimens were carefully examined with optical and scanning electron microscopy (SEM). None of them showed macroscopic or microscopic signs of corrosion, regardless of the environment to which the specimens were subjected. However, macroscopic evidence of mechanical fretting was present at the neck-stem modular junction, primarily concentrated at the medial contact point between stem and neck, especially for the prototype stems. SEM analysis confirmed these observations. The appreciable differences observed between the two designs suggest that the problem can be minimized or eliminated with an accurately designed taper fitting. © 1996 John Wiley & Sons, Inc.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
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