[Criteria for socket type prescription: indications and contraindications of a liner system]. / Verordnungskriterien für Oberschenkelschaftsysteme: Indikationen und Kontraindikationen der Linerversorgung.

BACKGROUND: The prescription of socket type for above-knee-amputees is based on clinical experience. There are no official guidelines. On the basis of treatment statistics and a patient survey, this study shows the indications and contraindications of a liner system. PATIENTS AND METHODS: Treatment statistics including data from the medical reports of 183 above-knee-amputees, who were treated in our clinic from 2003 to 2007 were analysed. 32 patients had a system change between liner- and contact-shaft accommodation and were contacted by telephone. The aim was to evaluate satisfaction with the current socket type and thus be able to compare types. RESULTS: A statistically significant relation in the treatment statistics between the quality of the stump and the socket type can be shown. A mesh graft to cover the stump, extreme volume fluctuation, low activity class and co-morbidities are the main reasons for the use of a liner system. Main reasons for a change to a liner system were the preservation of individual independence, better adhesion and skin problems. CONCLUSION: The developed clinical criteria can help physicians decide which socket type is most beneficial for each individual patient.

[Proximal femur replacement in revision arthroplasty]. / Der proximale Femurersatz in der Revisionsalloarthroplastik.

AIM: Today, megaendoprostheses--which were originally designed for osseous defect reconstructions in tumour surgery--are being more frequently used for extensive bone defects in revision arthroplasty. The purpose of this study was to assess the complication rate and the functional results associated with megaendoprosthesis reconstruction of the proximal femur in a non-oncological patient group. METHOD: 28 patients (average age 72; SD 10 years) with a proximal femur replacement were retrospectively (mean follow-up 43 months) evaluated regarding the complication rate. The Harris hip score was used to assess the outcome. The revision surgery was indicated because of large bone defects caused by implant-associated infection (n = 16), periprosthetic fracture (n = 8) or aseptic loosening (n = 4). RESULTS: Overall 8 patients (28.6 %) had to undergo 1 (n = 5) or more (2 n = 2, 4 n = 1) revision surgeries because of dislocation (n = 4), aseptic loosening of the stem (n = 2) and periprosthetic infection (n = 2). A significant pain relief could be achieved from on average 9.0 to 38.7 (according to the Harris hip score). All patients could be mobilised postoperatively, but walking aids were necessary for the majority of patients. CONCLUSION: A proximal femur replacement in revision arthroplasty should be regarded as a salvage procedure for restoration of extremity function. With this procedure it is possible to achieve a--limited--walking ability for patients who were immobilised preoperatively in most cases. Furthermore, pain relief can be achieved. However, the--mostly multimorbid--patients must be informed preoperatively about restrictions in daily life in order to avoid exorbitant expectations.

Development and evaluation of an experimental model for investigating the pathogenesis and therapeutic strategies of acute liver failure.

Because of the various etiologies of acute liver failure (ALF) a clinically relevant model must fulfill four criteria--reversibility, reproducibility, ALF-induced death, and a sufficient time interval for diagnosis and therapy between induction and death. In this study an experimental model was evaluated for these criteria. A total of 49 rats were randomized into seven groups: First, a pilot study was performed regarding the survival rate after different treatments: In group I, animals underwent a 70% liver resection. In group II, 70% liver resection was combined with ascending doses of postoperative endotoxin administration up to 400 microg/kg (group IIc). In group III, animals only underwent liver mobilization. In group IV, ALF was induced according to the protocol of group IIc, but with additional treatment of an endothelin-A-receptor (ETAR) antagonist. Animals in group V received only 400 microg endotoxin. After induction of ALF, all animals died within the first day, showing significantly elevated bilirubin and ammonium levels and severe damage to hepatocellular integrity. Application of the ETAR antagonist resulted in the survival of 6/7 animals until the 14th day; the biochemical and histomorphological changes were reversible. All other animals survived to the 14th day. A clinically relevant model of ALF in rats can be created by the combination of 70% liver resection and endotoxin application to produce an inflammatory component.

Achilles tendon healing: long-term biomechanical effects of postoperative mobilization and immobilization in a new mouse model.

The aim of the study was to investigate the long-term effects of postoperative immobilization as opposed to mobilization on the biomechanical attributes of healing Achilles tendons in a new experimental mouse model. In 114 Balb-C-mice the left Achilles tendon was transected and sutured by the Kirchmayr-Kessler technique. The tendons healed either under postoperative immobilization effected by fixing the upper ankle joint in equinus position or under mobilization through a limited range of movement. The contralateral Achilles tendons served as internal control. All tendons were tested biomechanically at short intervals up to the 112th postoperative day in terms of load to failure [N], tendon deflection [mm] and tendon stiffness [N/mm], and were evaluated histologically after 8 and 112 days. Postoperative mobilization resulted in a continuous and significantly more rapid restoration of load to failure in comparison to the immobilization group. Tendon deflection was decreased by postoperative mobilization, whereas under immobilization it paradoxically increased still further in the later course. After 112 days the tendons of the mobilization group had regained their original tendon stiffness, whereas the tendons after immobilization reached only about half the values seen in the control tendons. Histologically, postoperative mobilization led to increased immigration of inflammatory cells in the early phase. In the late phase, as compared to immobilization, tendon structure was more mature, with fibre bundles arranged in parallel and interposed tendocytes. Tensile loading of the healing tendon by postoperative mobilization leads to fundamental changes in the biological process of tendon healing resulting in accelerated restoration of load to failure and reduced tendon deflection.