Posterolateral plate fixation with Pantalarlock® is more stable than nail fixation in tibiotalocalcaneal arthrodesis in a biomechanical cadaver study.

BACKGROUND: Despite the promising results of ankle joint arthroplasty, the tibiotalocalcaneal (TTC) arthrodesis remains an established procedure in treatment of combined pathology of the ankle and subtalar joint. Despite the promising results in biomechanical investigations, nonunion rates of up to 24% are described in recent studies. The objective of this work was a comparative study of the biomechanical properties of the posterolateral plate fixation with retrograde intramedullary nail fixation. METHODS: Twenty four fresh-frozen human lower leg specimens (12 pairs) were used for the comparative biomechanical testing. Every specimen was preconditioned with 100 N over 200 cycles. After every 250 cycles the force was increased by 50 N from 200 to 600 N. This was followed by cyclic loading in dorsi-/plantiflexion with 800 N for 3000 cycles. All specimens were subjected to bone densitometry (DXA) and computed tomography. RESULTS: Significantly higher number of spacimens with nails (4) failed during the cycling testing in dorsi-/plantarflexion and futher two during the cyclic testing with 800 N. Two specimens with plates failed during the cyclic testing with 800 N. Statistical analysis showed that the specimens with the plate were significantly more stable in each test direction. The Pearson correlation demonstrated for the specimens with plate a linear relationship between the stiffness and the determined bone density. CONCLUSIONS: The results demonstrate a significantly superior stiffness of the Pantalarlock®-plate in all testing directions compared with the HAN nail. Probably the position of the plate on the tension side of the joint and the combination of locking and lag screws provide the higher stiffness of the plate system. The correlation of the stiffness with bone density leads to more predictable results of the plate arthrodesis. We hope for a reduction of the pseudarthrosis rate and shorten the postoperative treatment phase. The authors expect advantages in the treatment of high risk patients with severe deformity of the ankle, bone defects, neuropathic deformity, poor bone quality and osteoporosis.

Biomechanical results of percutaneous calcaneal osteotomy using two different osteotomy designs.

BACKGROUND: Percutaneous osteotomy of calcaneus has been proposed to reduce the complication rate and became more and more popular. The bone cut can be performed as a straight or chevron-like (V) osteotomy using a Shannon burr. Comparative studies of straight or V-osteotomy as like as one or two screws in percutaneous calcaneal osteotomies are missing in the literature. We hypothesize that the V-osteotomy will result in a higher stiffness in biomechanical testing as the straight osteotomy using single screw for fixation. METHODS: The straight osteotomy (9 fresh-frozen specimens) and V-osteotomy (9 fresh-frozen specimens) was performed and the calcaneal tuberosity was moved 10mm medially and slightly rotated. One 6,5mm cancellous compression screw was used for osteosynthesis. Specimens were preconditioned with 100N over 100 cycles. The force was increased after every 100N by 100N from 200 to 500N. This was followed by cyclic loading with 600N for 500 cycles. RESULTS: Despite the higher mean values of the group with V-osteotomy, no significant difference was registered between the two groups regarding the stiffness at all force levels. A higher failure rate was observed in the group with straight osteotomy. CONCLUSION: The moderate correlation of bone density and stiffness in the V-group, and significantly lower failure rate with no secondary dislocation in fluoroscopy indicates the superiority of the V-osteotomy in the present study. Whether the demonstrated advantages can be reflected in clinical practice should be investigated in further studies. LEVEL OF CLINICAL EVIDENCE: 5.

Early internationalization of students in a German medical school in the former German Democratic Republic.

The growing influence and importance of internationalization in higher education, especially in medical education, inspired anatomists at Columbia University New York, USA and at the Martin Luther University Halle-Wittenberg, Germany, to start a novel international preclinical collaboration project. As part of the anatomy dissection course a group of volunteer medical students from Halle dissected selected areas of the human body with the help of an English, illustrated, iPad-run dissection script (American Dissector). Meanwhile the rest of the students worked with a traditional German text-based dissector. Additionally, participating German students were matched with US students, with whom they connected via video-conferencing and discussed subjects like differences between their health care systems, structure and content of the anatomy course and the differences in their medical education systems. Questionnaires were sent for feedback and checklists confirmed dissection findings. Results indicated that the American Dissector was successfully shared internationally. The majority (62%) found it easier to find structures using the American Dissector compared to the standard dissector and also 62% needed the atlas two times less when using the American Dissector. Furthermore, students enjoyed their interaction with their international peers and the vast majority (77%) wished there were more interactions like this in the medical curriculum. This publication describes an approach to embed internationalization in the preclinical medical curriculum based in the gross anatomy course in a German Medical school, located in East Germany. Considering its history as a former German Democratic Republic faculty this is a meaningful step towardglobalization of medical education in this part of Germany.

Posterolateral plate fixation with Talarlock® is more stable than screw fixation in ankle arthrodesis in a biomechanical cadaver study.

BACKGROUND: A number of studies report on limitations of the screw arthrodesis in severe malalignment of the hindfoot, neuropathic deformity, poor bone quality and osteoporosis. METHODS: Fourteen anatomically correct polyurethane foam models of the right leg (Sawbones Europe, Malmö, Sweden) and eighteen fresh-frozen human lower leg specimens (9 pairs) were used for the comparative biomechanical testing. RESULTS: The statistical analysis of the stiffness of the fixation developed a significant difference in favor of the plate in all test directions. CONCLUSIONS: The excellent biomechanical results are very promising and we hope for a reduction of the pseudarthrosis rate and shorten the postoperative treatment phase.

Bodies of children in the Institute of Anatomy in Halle (Saale), Germany, between 1920 and 1945.

At the Institute of Anatomy and Cell Biology in Halle (Saale) 74 children's bodies of unknown historical provenance are being held in storage. The aim of this study was the evaluation of their identities, the circumstances of their acquisition, as well as the documentation of their individual characteristics. For these purposes, all bodies were comprehensively examined and photo-documented. Furthermore, CT-scans of 29 bodies were performed and information was collected from various local and national archives. Although most of the bodies were found to be those of stillborn children and infants, five children were between two and twelve years old, according to an age estimate by body-length and carpal bone analysis. The CT-scans revealed the cause of death for some of the children. The embalming method indicates that the bodies date from the first decades of the 20th century, and archival sources containing documents from 1920 to 1960 strongly suggest that these children's bodies were acquired by Institute of Anatomy between 1920 and 1942. During that period, a total of 2602 children's bodies were delivered to the Institute of Anatomy and registered in the communal burial records. At this point, there is no evidence that these children might have been victims of National Socialist crimes. It is planned to give them a dignified burial.

Significantly enhanced lung metastasis and reduced organ NK cell functions in diet-induced obese rats.

BACKGROUND: Obesity was identified as a major risk factor for malignant diseases, but underlying mechanisms remain unclear. Natural killer (NK) cells, a pivotal aspect of innate immunity, are capable of identifying and killing virally infected and tumor cells. Previous studies have shown altered NK cell functions in obesity, and the current study aimed to investigate the relationship between altered NK cell functions and increased cancer risk in obesity. METHODS: To induce obesity male F344-rats received a high-fat diet (34% fat) or a control diet (4% fat). Thereafter, syngeneic mammary adenocarcinoma cells (MADB106) or a vehicle were intravenously (i.v.) injected. 15 min after injection, half of each group of rats were killed, lungs removed and immunohistochemically stained. Numbers of NK cells, MADB106 cells and NK cell-tumor cell interactions were quantified. Twenty-one days after tumor-cell injection the other half group of rats was killed and lung metastases were counted and relative mRNA concentrations of different NK cell receptors were determined. RESULTS: After short-term MADB106-challenge, DIO fed animals showed significantly decreased NK cell numbers in the blood and NK cell-tumor cell interactions in the lung as compared to their control littermates. Twenty-one days after MADB106 injection, the lungs of the DIO fed rats showed significantly more lung metastases compared to control animals, accompanied by reduced relative mRNA concentrations of the activating NK cell receptor NKG2D. CONCLUSIONS: We conclude that induction of obesity in F344-rats leads to reduced lung NK cell function against tumor cells and results in significantly enhanced lung metastasis as compared to lean animals. It can be hypothesized that obesity-induced altered NK cell functions play an important role in cancer growth and metastasis.

Comparison of anthropometric characteristics between professional triathletes and cyclists.

Anthropometric characteristics of athletes are considered to be an important determinant of success in sport. The aim of the present study was to compare several anthropometric parameters and subjective characteristics of professional elite triathletes with anthropometric profiles of professional cyclists and sportive students. In total 93 volunteers (21 male and female triathletes, 26 male cyclists and as a control group 46 male and female students) participated in this study. Eight different anthropometric parameters were measured and a five-page questionnaire containing 35 general questions had to be completed. Interestingly, there were no significant differences between the arm span, the lengths of the lower limb and the circumference of waist and hip between male triathletes and cyclists. As expected, the athletes had significantly lower heart rates and lower weights as compared to the controls. Further results showed that male cyclists had a higher BMI, larger thighs and were taller as compared to the male triathletes. The present study could not evaluate specific anthropometric characteristics as predictive factors of performance in elite athletes. Thus, individual successful performance is linked to discipline and talent rather than to a specific anthropometric profile.