[Reconstruction of soft tissue defects of the lower extremities]. / Rekonstruktion von Weichteildefekten an der unteren Extremität.

A reliable reconstruction of soft tissue defects of the lower extremities especially in the distal third of the leg is still a special challenge for reconstructive surgeons. The possibility of salvaging the leg has to be evaluated in the setting of an interdisciplinary team and the timing of the operation(s) with respect to the safety of the patient and a systematic approach with the selection of a suitable flap have to be defined. Traditionally local muscle flaps or free flaps have been established for coverage of defects of the lower extremities. Recently perforator-based flaps have gained popularity for reconstruction of lower extremity defects. Furthermore, new surgical techniques and developments in association with the demographic change have led to a paradigm shift.

[Pest control in your garden - a case series of severe hand injuries caused by privately used explosives and shot traps]. / Schädlingsbekämpfung im eigenen Garten - Fallserie schwerer Handverletzungen durch Spreng- und Schussfallen in privatem Gebrauch.

Booby traps and gun-like devices for vole control can lead to complex trauma requiring emergency medical care. We present a case series of patients who suffered severe hand and facial trauma through detonation of booby traps and paraphernalia (n = 9, Ø 60 years of age). All patients were admitted to the emergency department of Hannover Medical School for primary care. Between 2011 and 2015 we treated six patients with hand trauma due to gun-like devices, two patients with hand trauma due to booby traps, and one patient with injury to the face including eyes due to a gas cartridge explosion. All hand trauma patients (n = 8) showed injuries of the soft tissue. Six of these patients also presented fractures or lesions of capsular or tendon structures. Therapies included debridement as well as skin grafts or flaps for tissue defect coverage. We informed the Department for Commercial Safety (Gewerbeaufsicht Hannover) in 2014 because we believe that these traps pose a serious safety hazard.

[Nerve injuries and posttraumatic therapy]. / Nervenverletzungen und posttraumatische Versorgung.

Peripheral nerve injuries are a common clinical problem and can represent a major challenge, especially after trauma. In order to achieve optimal therapy, an early and adequate diagnosis with subsequent therapy is critical for functional preservation and restoration. Especially after complete severance of a peripheral nerve, the surgical techniques for nerve coaptation are an important prerequisite for peripheral nerve regeneration. The importance and necessity of adequate nerve coaptation and nerve transplantation are presented in detail. In addition, the types of primary and secondary nerve reconstruction procedures are described as well as the optimal time point of nerve repair. This article provides a comprehensive overview of the possibilities for diagnosis and intervention after nerve injury, additionally including an algorithm for surgical intervention. Furthermore, possible pitfalls and factors for improving the functional outcome are presented to optimize results with trauma-related nerve injury.

[Registry Research Funding of the German Society of Plastic, Reconstructive and Aesthetic Surgery (DGPRÄC) and Research Funding Report 2021/2022]. / Register Forschungsförderung der Deutschen Gesellschaft für Plastische, Rekonstruktive und Ästhetische Chirurgie (DGPRÄC) und Forschungsförderungs-Bericht 2021/2022.

BACKGROUND: Research is an integral part of academic medicine. In plastic surgery, it sets the course for innovations in the specialty. The purpose of this study is to present the research performance of plastic surgeons in Germany for the period 2021/2022 and to compare it with previous periods. MATERIALS AND METHODS: The directors of plastic surgical academic institutions reported all requested/approved and rejected research applications to public, non-public and industrial funding organizations. Data was gathered within an established online database. In addition, the DFG´s public database GEPRIS was screened for plastic surgical research grants. Data was also collected regarding research infrastructure and organization at the participating centers. RESULTS: 105 applications were reported to 54 different funding agencies from 20 plastic surgery centers. 37 funding applications were submitted to the major public funding agencies DFG, BMBF, BMWi, BMG, BMVg, G-BA and EU. Of these, 59,5% (22/37) were DFG, 13,5% (5/37) each BMBF and EU, 5,4% (2/37) BMWi, and 2,7% (1/37) each BMG, BMVg, and G-BA applications. The average funding volume of these proposals was 401,515 euros. Approved DFG proposals were most frequently assigned to the review board 205-27 Orthopedics, Trauma Surgery, Reconstructive Surgery (n=10/16, 62,5%). Over time, the research registry shows an increase in the number of proposals in general and those granted. 70,0% (14/20) of participating sites had their own experimental research laboratory, while only 40,0% (8/20) had their own clinical trial center. CONCLUSION: The 2021/2022 Research Funding Report once again highlights the impressive research accomplishments of the plastic surgery community.

[One-stage defect closure of deperiosted bone and exposed tendons with MATRIDERM® and skin transplantation. Possibilities and limitations]. / Einzeitige Defektdeckung von denudiertem Knochen und freiliegenden Sehnen mittels MATRIDERM® und Spalthaut. Möglichkeiten und Grenzen.

BACKGROUND: Full-thickness skin defects over functional structures (tendons, vessels) or deperiosted bones of the extremities usually require extensive soft tissue reconstruction to cover the defect. A new option for coverage of the defect is the application of MATRIDERM®, a bovine matrix consisting of collagen and elastin, as a neodermis underneath skin transplants. Can this combined one-stage surgical intervention successfully cover deperiosted bone or tendon? PATIENTS AND METHODS: We performed this one-stage procedure in ten patients instead of soft tissue reconstruction. The success of wound coverage with the one-stage method and in combination with skin transplantation for defects generally associated with considerable loss of transplants (deperiosted bones and tendons without paratenons) was determined. RESULTS: In nine of ten patients, complete defect coverage could be achieved. A one-stage wound closure in extensive defects with exposed tendons in four of five locations could be achieved. In deperiosted bone defects the one-stage coverage was only successful in two of six patients. However, complete wound closure could be achieved with a second skin transplantation in a patient with exposed tendon and bone in three of the four locations. CONCLUSION: As a one- or two-stage procedure, MATRIDERM® application with skin transplantation resulted in an effective defect closure without the need for a complex plastic reconstructive procedure. With regard to its functionality it cannot be considered as a substitute for skin flaps. In selected cases MATRIDERM® is an interesting and successful method in plastic reconstructive surgery.

Spider silk nerve graft promotes axonal regeneration on long distance nerve defect in a sheep model.

Peripheral nerve injuries with substantial tissue loss require autologous nerve transplantation or alternatively reconstruction with nerve conduits. Axonal elongation after nerve transection is about 1 mm/day. The precise time course of axonal regeneration on an ultrastructural level in nerve gap repair using either autologous or artificial implants has not been described. As peripheral nerve regeneration is a highly time critical process due to deterioration of the neuromuscular junction, this in vivo examination in a large animal model was performed in order to investigate axonal elongation rates and spider silk material degradation in a narrowly delimited time series (20, 30, 40, 50, 90, 120, 150 and 180 days) by using a novel spider silk based artificial nerve graft as a critical prerequisite for clinical translation. Autologous nerves or artificial nerve conduits based on spider silk of the spider species Trichonephila edulis were transplanted in a 6.0 cm nerve defect model in the black headed mutton. At each of the post-implant time point, electrophysiology recordings were performed to assess functional reinnervation of axonal fibers into the implants. Samples were analyzed by histology and immunofluorescence in order to verify the timeline of axonal regeneration including axonal regeneration rates of the spider silk implant and the autologous transplant groups. Spider silk was degraded within 3 month by a light immune response mainly mediated by Langhans Giant cells. In conjunction with behavioral analysis and electrophysiological measurements, the results indicate that the spider silk nerve implant supported an axonal regeneration comparable to an autologous nerve graft which is the current gold standard in nerve repair surgery. These findings indicate that a biomaterial based spider silk nerve conduit is as effective as autologous nerve implants and may be an important approach for long nerve defects.

[Registry Research Funding of the German Society of Plastic, Reconstructive and Aesthetic Surgeons (DGPRÄC) and Research Funding Report 2019/2020]. / Register Forschungsförderung der Deutschen Gesellschaft der Plastischen, Rekonstruktiven und Ästhetischen Chirurgen (DGPRÄC) und Forschungsförderungsbericht 2019/2020.

BACKGROUND: Since 2015/16 the DGPRÄC collects, evaluates and publishes the research activities of academic sections, departments and clinics for plastic surgery at university hospitals in Germany, in order to raise the awareness of plastic surgical research performance. MATERIALS AND METHODS: The directors of plastic surgical academic institutions were contacted via the DGPRÄC and asked to report any requested/approved and rejected research applications to public, non-public and industrial funding organizations. Data was collected in our previously established online database: https://docs.google.com/forms/d/e/1FAIpQLSe6F5xmTyw-k7VKJx_2jkPA4LBXsA0sgBGMrC3rx_4bHj6uzQ/viewform?usp=sf_link. In addition, applications were identified via the DFG's public database GEPRIS. RESULTS: A total of 41 funding applications to the public funding institutes DFG, BMBF, BMWi, BMG and EU were identified. 75.6 % (31/41) of the applications had already been approved at the time of data collection, of which 77.4 % (24/31) were DFG, 9.7 % (3/31) were BMWi, 6.5 % (2/31) were EU and 3.2 % (1/31) were BMBF or BMG applications. The average funding amounted to 358 301 Euro. In 50.0 % (12/24) of the cases, the approved DFG proposals were assigned to the subject review board 205-27 Orthopedics, Trauma Surgery, Reconstructive Surgery. CONCLUSION: The continuous publication of plastic surgical research funding reports submitted by the convention of university plastic surgeons of the DGPRÄC portraits the excellent, collaborative research activity in the field of plastic surgery.

[Bases and methods of suturing]. / Grundlagen und Techniken der chirurgischen Naht.

If pharmaceutic modulation of scar formation does not improve the quality of the healing process over conventional healing, the surgeon must rely on personal skill and experience. Therefore a profound knowledge of wound healing based on experimental and clinical studies supplemented by postsurgical means of scar management and basic techniques of planning incisions, careful tissue handling, and thorough knowledge of suturing remain the most important ways to avoid abnormal scarring. This review summarizes the current experimental and clinical bases of surgical scar management.

Sepsis caused by multidrug-resistant klebsiella pneumoniae infection in a 23-year-old burn patient: case report and literature review.

Septic complications are a major problem in burn care. Infections caused by multidrug-resistant (MDR) Klebsiella pneumoniae strains represent a growing threat. In particular, Romania has seen rapidly increasing rates of MDR Klebsiella pneumoniae isolates in recent years. The PubMed database was searched with the terms 'Klebsiella pneumoniae', 'multiple drug resistant', 'enterobacteria', 'infection', 'sepsis or septicaemia or blood stream infection', 'surveillance', 'diagnose', 'burn', 'intensive care unit' and 'Romania or Europe'. In addition, the case of a burn patient who suffered from sepsis caused by MDR Klebsiella pneumoniae and who was treated at our burn intensive care unit (ICU) was reviewed. The 23-year-old male was initially treated in Romania, but after 48 hours he was transferred to our burn ICU. Initially, the treatment course was appropriate and sufficient wound healing was achieved by day 27. However, the patient's condition deteriorated rapidly on day 28 and blood culture analysis showed growth of MDR Klebsiella pneumoniae. Despite intensive medical therapy, the patient died as a result of multiple organ failure (MOF) on day 44. Sepsis caused by MDR Klebsiella pneumoniae represents an enormous therapeutic challenge. Burn patients who are transferred from Southeast Europe would likely benefit from an intensified screening for MDR pathogens.

Les accidents septiques sont une préoccupation majeure en brûlologie. Celles dues à Klebsiella pneumoniæ multirésistante (KP-BMR) sont en augmentation, particulièrement rapide ces dernières années en Roumanie. Nous avons effectué une recherche PubMed avec les critères « Klebsiella pneumoniæ ¼, « multirésistant ¼, « entérobactérie ¼, infection ¼, « sepsis ¼, septicémie ¼, « surveillance ¼, « diagnostic ¼, « brûlure ¼, « unité de soins intensifs ¼, « Roumanie ¼, « Europe ¼, à la suite du cas d'un patient de 23 ans, transféré dans notre service en provenance de Roumanie, à sa 48ème heure d'hospitalisation. La couverture cutanée était terminée à J27. Á J28, son état s'est rapidement dégradé et les hémocultures sont revenues positives à KP-BMR. Le patient est décédé à J44, dans un tableau de défaillance multiviscérale. Les infections à KP-BMR représentent un formidable défi. Les patients en provenance d'Europe du Sud-Est devraient bénéficier d'un screening bactériologique à la recherche de BMR.

Are we bound to our scores? a 74-year-old patient with an abbreviated burn severity index of 14.

We report a case of a 74-year-old female patient who was involved in a car accident. The patient suffered deep dermal and full thickness burns and the probability of survival calculated with the Abbreviated Burn Severity Index (ABSI) was extremely low. The patient showed sufficient cardiorespiratory and renal function for the entire treatment period. An epifascial necrosectomy of all four limbs was performed on day three after admission. Wound coverage was performed using the MEEK technique and split skin grafts. The patient was bedded in a FluidAir bed, which enabled the burn wounds on the back to dry and heal in large part. After four surgical procedures and four months of treatment at the burn ICU, the patient was sufficiently mobilized for transfer to a hospital in her home region. The aim of the following case report is to demonstrate that burn patients with very low chances of survival can be treated successfully.

Nous rapportons le cas d'une patiente de 74 ans victime d'un accident de voiture. Elle souffrait de brûlures intermédiaires et profondes et ses chances de survie, selon le score ABSI, étaient extrêmement faibles. Elle a présenté des signes d'insuffisance cardiaque et rénale durant toute son hospitalisation. Une avulsion au niveau des 4 membres a été réalisée à J3. La couverture cutanée a été réalisée par greffes expansées et technique de Meek. Elle a été installée sur un lit fluidisé, ce qui a permis la guérison d'une bonne partie des brûlures postérieures. Elle a pu sortir de l'unité spécialisée de soins intensifs au bout de 4 mois, ayant subi 4 interventions chirurgicale. Elle a alors été transférée dans l'hôpital de sa région. Ce cas clinique a pour but de montrer que même des patients au pronostic très sombre peuvent survivre.

[Registry Research Funding of the German Society of Plastic, Reconstructive and Aesthetic Surgeons (DGPRÄC) and Research Funding Report 2017/2018]. / Register Forschungsförderung der Deutschen Gesellschaft der Plastischen, Rekonstruktiven und Ästhetischen Chirurgen (DGPRÄC) und Forschungsförderungs-Bericht 2017/2018.

INTRODUCTION: This report serves to publicize the research of academic institutions for Plastic Surgery within our society DGPRÄC in 2017/2018 and sequels the funding report of 2015/2016. Applications to public, non-public, or industrial funding organizations were evaluated. At the same time, this paper analyses the number of approved DFG applications in Plastic, Thoracic and Vascular Surgery in the GEPRIS system. Contrary to these specialties, Plastic Surgery is not classified as an independent speciality in the subject structure of the DFG review board which results in a lack of transparency concerning Plastic Surgery research work. MATERIALS AND METHODS: Our previously established online database (https://docs.google.com/forms/d/1OaSnHyKTysawiI1ie7kfUxDf7nJP_RiTUJTsnb7Mq_E/edit) for reporting requested/ approved and rejected research applications to public, non-public and industrial funding organizations was continued and evaluated together with applications found in the DFG's public database GEPRIS. RESULTS: Compared to the previous year's report, the number of approved applications from public research organizations (DFG, BMBF, BMWi, EU) was increased from 23 to 27. We identified 19 approved DFG applications from Plastic Surgery, as compared to 9 and 8 applications by Thoracic and Vascular Surgery, respectively. SUMMARY: Taken together, this data emphasizes that our research is at least equal to that of other newly established surgical specialties within the framework of the DFG. Accordingly, we hope to provide further arguments for an adaptation of the DFG review boards subject structure to include Plastic Surgery as an independent specialty as it is for Vascular Surgery and Thoracic Surgery.

Demyelinating diseases and potential repair strategies.

Demyelination is associated with a number of neurological disorders including multiple sclerosis (MS), spinal cord injury and nerve compression. MS lesions often show axon loss and therefore reparative therapeutic goals include remyelination and neuroprotection of vulnerable axons. Experimental cellular transplantation has proven successful in a number of demyelination and injury models to remyelinate and improve functional outcome. Here we discuss the remyelination and neuroprotective potential of several myelin-forming cells types and their behavior in different demyelination and injury models. Better understanding of these models and current cell-based strategies for remyelination and neuroprotection offer exciting opportunities to develop strategies for clinical studies.

[Plastic reconstruction of radiation injuries]. / Plastische Rekonstruktion von Strahlenfolgen.

In addition to surgical and drug therapy, radiotherapy (or radiation therapy) is one of the three mainstays of modern oncological therapy regimes. It uses ionizing radiation to control tumors by damaging the DNA of cancerous tissue leading to cellular death. Although advances have been made in recent years resulting in a reduced dosage to the surrounding tissues, radiation injuries and tissue-related side effects cannot be completely avoided. Knowledge of the pathophysiology, treatment modalities and interdisciplinary treatment approaches are essential for effective therapy whilst limiting side effects. Surgery within the irradiated area is technically demanding due to tissue alterations and unpredictable wound healing. The plastic reconstructive surgeon either faces the challenge of delayed wound healing following neoadjuvant radiation or chronic radiation-linked changes following previous radiotherapy, which can also occur after a latency period of many years. Reconstructive interventions can be essential to repair deficits of a functional and/or aesthetic nature in order to maintain a high quality of life for oncology patients. This can also be of benefit to patients in a palliative oncological setting to improve daily functions and quality of life.

Interdisciplinary reconstruction of oncological resections at the skull base, scalp and facial region.

Extensive bone and soft tissue defects of the skull require unique plastic and reconstructive techniques to avoid and optimize aesthetic appearance following oncological resections. Procedures are ideally planned in an interdisciplinary board composed of neurosurgery, otorhinolaryngology, plastic and reconstructive surgery to facilitate reconstructive procedures of soft tissue and bone as early as possible in one approach. Large resections may require plastic surgery involvement from the beginning. Herein, we describe the function of a multidisciplinary approach to complex oncologic resections of the cranial base, scalp, and facial regions for neuro-oncologic patients.

Role of endochondral ossification of articular cartilage and functional adaptation of the subchondral plate in the development of fatigue microcracking of joints.

The mechanisms that regulate functional adaptation of the articular ends of long bones are poorly understood. However, endochondral ossification of articular cartilage and modeling/remodeling of the subchondral plate and epiphyseal trabeculae are important components of the adaptive response. We performed a histologic study of the distal end of the third metacarpal/metatarsal bone of Thoroughbreds after bones were bulk-stained in basic fuchsin and calcified sections were prepared. The Thoroughbred racehorse is a model of an extreme athlete which experiences particularly high cyclic strains in distal limb bones. The following variables were quantified: microcrack boundary density in calcified cartilage (N.Cr/B.Bd); blood vessel boundary density in calcified cartilage (N.Ve/B.Bd); calcified cartilage width (Cl.Cg.Wi); duplication of the tidemark; and bone volume fraction of the subchondral plate (B.Ar/T.Ar). Measurements were made in five joint regions (lateral condyle and condylar groove; sagittal ridge; medial condylar and condylar groove). N.Cr/B.Bd was site-specific and was increased in the condylar groove region; this is the joint region from which parasagittal articular fatigue (condylar) fractures are typically propagated. Formation of resorption spaces in the subchondral plate was co-localized with microcracking. N.Ve/B.Bd was also site-specific. In the sagittal ridge region, N.Ve/B.Bd was increased, Cl.Cg.Wi was decreased, and B.Ar/T.Ar was decreased, when compared with the other joint regions. Multiple tidemarks were seen in all joint regions. Cumulative athletic activity was associated with a significant decrease in B.Ar/T.Ar in the condylar groove regions. N.Cr/B.Bd was positively correlated with B.Ar/T.Ar (P < 0.05, r(s) = 0.29) and N.Ve/B.Bd was negatively correlated with B.Ar/T.Ar (P < 0.005, r2 = 0.14) and Cl.Cg.Wi (P < 0.05, r2 = 0.07). We conclude that endochondral ossification of articular cartilage and modeling/remodeling of the subchondral plate promote initiation and propagation of site-specific fatigue microcracking of the joint surface, respectively, in this model. Microcracking of articular calcified cartilage likely represents mechanical failure of the joint surface. Propagation of microcracks into the subchondral plate is a critical factor in the pathogenesis of articular condylar fatigue (stress) fracture. Functional adaptation of the joint likely protects hyaline cartilage from injury in the short-term but may promote joint degeneration and osteoarthritis with ongoing athleticism.

Two thyroid hormone-mediated gene expression patterns in vivo identified by cDNA expression arrays in rat.

Thyroid hormone (T3) is essential for normal development, differentiation and metabolic balance. Only a limited number of T3-target genes have been identified so far and their complex regulation pattern is poorly understood. We performed cDNA expression array hybridisation to identify T3-regulated genes and to investigate their expression pattern after various time points in vivo. Radioactively labelled cDNA was prepared from hepatic RNA of hypothyroid and hyperthyroid rats 6, 24 and 48 h after the administration of T3. Labelled cDNA probes were hybridised to rat Atlas Arrays. Twenty-three of 588 genes were shown to be differentially regulated, 18 of which were previously not known to be regulated by T3. The expression of 19 genes was verified by independent northern blot hybridisation. Two different expression time courses of T3 expression were observed. In a first expression profile ('early' expression) the transcription level of the target genes rises within 6 h, drops by 24 h and increases again within 48 h after the administration of T3. In a second expression profile ('late' expression) the mRNA level rose in the first 6 h and rose further by 48 h, indicating an additional regulation mechanism. Nuclear respiratory factor (NRF)-1 and peroxisome proliferator-activated receptor gamma coactivator 1 (PGC-1), but not NRF-2, were up-regulated within 6 h after T3 administration, suggesting NRF-1 and/or PGC-1 as key regulators for mediating the 'late' expression pattern.

[Analysis of Critically Perfused Tissues by Laser Speckle Contrast Analysis (LASCA) Perfusion Imaging]. / Quantitative Perfusionsanalyse durch Laser Speckle Contrast Analysis (LASCA) Perfusions-Imaging von kritisch perfundierten Geweben Quantitative Perfusion.

Background: The success of tissue transplantation and long-term tissue stability after wound healing depends on sufficient tissue perfusion. Laser Doppler-supported procedures allow for an objective measurement of relative tissue perfusion. The development of Speckle-based Laser Doppler imaging now enables a real-time representation of tissue perfusion. The perfusion of tissues relevant in plastic surgery such as scars, phalangeal replantations and burn wounds were systematically analysed by Laser Speckle Contrast Analysis (LASCA) imaging. Method: Perfusion of skin, scars, replanted fingers and different burn wound degrees (IIa, IIb and III) were systematically examined by LASCA imaging. Baseline perfusion of control tissue and perfusion values of compromised tissues were quantified and compared. Results: LASCA imaging shows significant differences in baseline perfusion of skin compared to atrophic scars, hypertrophic scars and keloids. Finger replantations with subsequent replantation failure show a characteristic and significant hypoperfusion in line with the expected clinical feature. A significant difference in tissue perfusion is seen in superficial (IIa) and superficial deep (IIb) burns, which are hard to distinguish on clinical examination. Deep burns (III) are characterised by hypoperfusion, which differs significantly from grade IIa and IIb burn wound perfusion, but not from baseline skin perfusion. Furthermore, the characteristic perfusion values of different burn degrees correspond to the varying treatment strategies. Conclusion: LASCA imaging is a robust method of perfusion imaging, which combines high resolution and speed. Hypoperfusion of tissues relevant to plastic surgery such as scars, phalangeal replantations and the different burn degrees (IIa, IIb and III) can be detected by LASCA imaging with high precision. Ease of use and immediate real-time imaging make LASCA imaging a reliable tool for the evaluation of tissue perfusion after plastic surgery procedures, which may influence further treatment decisions.

Electrospinning induced surface activation (EISA) of highly porous PMMA microfiber mats for HIV diagnosis.

This work presents an Electrospray Induced Surface Activation (EISA) method generalization for electrospinning. It allows an easy way to produce surface functionalized microfiber mats for infectious disease diagnostic purposes. We present the details of both the production and characterization of surface functionalized highly porous poly methyl methacrylate (PMMA) microfiber mats produced using dry (DS) and wet substrate (WS) configurations. The characterization was performed using high-resolution scanning electron microscopy (HRSEM), Size Exclusion Chromatography (SEC), X-ray photoelectron spectroscopy (XPS) and biological essays attaching both the recombinant auto-fluorescent green fluorescent protein (GFP) and the anti-human Ig protein containing a fluorescent reporter R-phycoerythrin (AbPE). The final biological application assay was performed by positively detecting HIV contaminated human samples.

Up-regulation of site-specific remodeling without accumulation of microcracking and loss of osteocytes.

Functional adaptation of bone normally protects the skeleton from fracture during daily activity. Accumulation of microcracking and loss of osteocytes have been implicated in the regulation and initiation of targeted (reparative) remodeling of bone and, in certain situations, the development of fatigue or stress fracture. We performed a histologic study of the dorsal cortex of the mid-diaphysis of the third metacarpal (Mc-III) bone of Thoroughbred racehorses after bones were bulk-stained in basic fuchsin and transverse calcified sections were prepared. The Thoroughbred racehorse is an extreme athlete whose Mc-III bone experiences particularly high cyclic strains during training and racing. A group of non-athletic horses was also included in the experiment. The following variables were quantified: activation frequency (Ac.f); bone formation rate (BFR); resorption space density (Rs.N/T.Ar); microcrack density (Cr.Dn); microcrack mean length (Cr.Le); microcrack surface density (Cr.S.Dn); osteocyte density (Ot.N/T.Ar; Ot.N/B.Ar); and bone volume fraction (B.Ar/T.Ar). Ac.f and BFR were estimated using a mathematical algorithm. Using confocal microscopy, bones were examined for fine microcracks, diffuse matrix injury, and disruption of the osteocyte syncytium. Low values for Cr.Dn (#/mm2) were found in both groups (0.022+/-0.008 and 0.013+/-0.006 for racing Thoroughbreds and non-athletic horses, respectively). There was no significant relationship between Cr.Dn and Ot.N/T.Ar; Ot.N/B.Ar, B.Ar/T.Ar, and Ot.N/T.Ar; Ot.N/B.Ar, and remodeling (Ac.f, Rs.N/T.Ar) and Ot.N/T.Ar; Ot.N/B.Ar. Intense remodeling of the Mc-III dorsal cortex was found in the racing Thoroughbreds (Ac.f 12.8+/-7.4 #/mm2/year; BFR 31.5+/-15.6%; Rs.N/T.Ar 0.19+/-0.09 #/mm2) and was significantly increased compared with non-athletic horses. Overall, remodeling was weakly correlated with Cr.Dn (r2=0.15, P<0.05). Subtle matrix injury, not detectable by bright-field microscopy, was particularly evident adjacent to resorption spaces in Thoroughbred bone. In non-athletic horses, disruption of the dendritic cell processes of osteocytes associated with cement lines and interstitial fragments was more evident. Taken together, these findings suggest that site-specific (targeted) induction of remodeling during functional adaptation of bone in a high-strain skeletal site is not dependent on accumulation of microcracking or loss of osteocytes. We hypothesize that athleticism can directly influence bone turnover in this extreme athlete through pathways that do not involve classical linear microcracks.

[Skin and soft tissue complications after orthopedic interventions on tumors : interdisciplinary management]. / Haut- und Weichteilkomplikationen nach tumororthopädischen Eingriffen : Interdisziplinäres Management.

Interdisciplinary collaboration between orthopedic and plastic surgeons is indicated in reconstructive surgery of the extremities for both traumatic orthopedic fractures with extensive soft tissue damage and musculoskeletal tumor resection. We want to emphasize the need for close cooperation starting in the preoperative planning for reconstruction after tumor resection in order to discuss and establish a unified approach. This is particularly important to establish a joint approach with special consideration of possibly necessary adjuvant therapies. One collaborative approach is for the orthopedic surgeon to resect the tumor and the plastic surgeon to carry out the defect reconstruction for exclusive soft tissue coverage including flap surgery as well as for functional reconstruction depending on the location and extent of tumor resection. Thus, careful preoperative and postoperative communication on the precise location, extent of tumor resection and the therapy timing between the orthopedic surgeon and the plastic surgeon will allow the most effective subsequent repair of the resection site.