In this study it is demonstrated that the combined chemical and mechanical influences of the implant situation cause property changes of ultra-high-molecular-weight polyethylene (UHMWPE) hip joint cups. Nearly 250 loosened hip cups, retrieved 3 weeks to 14 years after implantation, were investigated. The clinical long-term behavior of various shaped polyethylene hip sockets are statistically analyzed. The main damage features were defined and described. Density measurements show a density increase with implantation time and a dependence of these changes from implant position and loading conditions. The rate of extractable constituents also increases with course of time. An increased in vivo conditioned oxidation of the UHMWPE can be demonstrated by infrared (IR) spectrometry. The density increase can be explained by post-crystallization, which is the result of oxidative chain scission. This leads to a reduction of the average molecular weight of the PE and to an increased extractability of constituents. Since these changes have been recognized as the reasons for aging and failing of UHMWPE, the methods of material characterization used in this study for retrieved implants will help to develop suitable in vitro testing and simulating methods. Characteristic damage features of hip cups allow direct relationships with construction characteristics and their improvement.
The treatment of thermally injured hands has changed in the last 20 years. An early necrectomy and grafting with split-skin grafts is recommended by most burn specialists. The outcome in regard to cosmetic and functional results could be improved by early grafting. Meanwhile unnecessary grafts in burns with indeterminate depth can be avoided by new skin replacements. The new epithelial substitute Suprathel is marked by a considerable reduction of pain if it is applied on second degree burns. Therefore the mobilisation of the burned patient can be accelerated. Many hand burns were treated by Suprathel in our burn centre without severe scarring and without loss of function. We treated 76 inpatients with thermally injured hands in our burn centre from January 2004 to July 2006. Only 28 (25.7 %) of all 109 afflicted hands required a primary skin grafting. Suprathel was applied primarily in 78 hands (71.6 %). 3 hands were treated otherwise. 8 of the hands which were primarily treated by Suprathel (10.3 %) required a well-aimed grafting after one or two weeks, 70 (89.7 %) had a complete epithelisation without grafting. Many skin grafts could be avoided. We modified our strategy for the treatment of burned hands by our excellent experiences with Suprathel.
A total of 301 patients with thoracoabdominal lesions had concomitant craniocerebral lesions (69.1%) and injuries of the locomotor system (66.1%). In 65.4% operative intervention was necessary, while 34.6% could be primarily treated conservatively. Operative emergency therapy was required in the thorax in 34.7%, and in the abdomen in 50%. Under these conditions, the mortality for the thorax was 70.6% and for the abdomen 40.5%. As a result of mostly combined causes (66%), 101 patients died (33.6%). Multiple organ failure was in the high range (80%), while the most frequent single cause of death was craniocerebral trauma, ranking before thoracic and abdominal traumata.
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