[Coverage of complex pararectal pelvic defects: role of the free myocutaneous musculus vastus lateralis flap]

BACKGROUND

In the event of an advanced rectal carcinoma, an evisceration with rectal amputation may become necessary. The resulting defects, due to their extent, depth, or local tissue damage from previous surgeries and radiation, can in many cases only be closed through free microvascular tissue transfer. In this case series, we demonstrate the successful combination of a musculocutaneous musculus vastus lateralis flap (MVL) with a direct connection to the superior gluteal artery.

MATERIALS AND METHODS

Over a 47-month period, we retrospectively examined 11 cases of patients with dorsal pelvic defects after evisceration and rectal amputation that could not be closed using local or regional means. In cases of extensive defects with deep pararectal wound cavities, all these patients underwent defect coverage through a free myocutaneous MVL flap with a direct vascular anastomosis to the superior gluteal vessels.

RESULTS

The mean defect size was 290.0 cm² (SD: 131.2; range: 200-600 cm²). The mean defect depth was 10.5 cm, necessitating MVL flap reconstruction with an average size of 336.3 cm². Three operative revisions were required due to postoperative bleeding. There were no arterial or venous thromboses, and no flap loss occurred. Only one necrosis of a distal flap tip was observed, which could be corrected secondarily by direct suturing. The case-mix evaluation yielded an average value of 24.251 (SD: 21.699; range: 7.036-65.748) points, emphasizing the complexity of the cases.

CONCLUSIONS

Our results indicate that a free microvascular MVL flap is a viable therapeutic option for pararectal defects that cannot be closed by local or regional methods. The superior gluteal artery proves to be a safe and sufficient vascular connection. In combination, even extensive defects can be successfully closed.

[Breast implant-associated squamous cell carcinoma: a systematic literature review]

BACKGROUND

Breast implant-associated squamous cell carcinoma (BIA-SCC) is being discussed as a distinct malignant tumour entity originating from the implant capsule. The FDA and the ASPS published a safety communication on BIA-SCC in 2022, with a first case report of BIA-SCC having been published in the 1990s. This manuscript summarises the current scientific data on this rare tumour entity.

MATERIAL AND METHODS

This systematic literature review from two independent databases includes all publications of cases with histopathologically confirmed BIA-SCC. Data extraction included study design, demographic data, implant information and details regarding diagnosis and treatment.

RESULTS

Nineteen cases of BIA-SCC with a mean age of 57±10 years were reported in 16 publications. In most cases, the indication was aesthetic augmentation (n=13). Both silicone (n=11) and saline (n=7) implants with different surfaces (smooth n=3, textured n=3, polyurethane n=1) were used. Symptoms such as unilateral swelling (n=18), pain (n=14) and erythema (n=5) occurred on an average of 23±9 years after implantation. Imaging showed fluid collection (n=8) or a tumour mass (n=4) around the breast implant. The most common surgical treatment was explantation with capsulectomy. Metastasis was described in 6 cases.

CONCLUSIONS

BIA-SCC is a malignant tumour entity associated with breast implant capsules. Based on current low-quality data (level of evidence class V), no definitive conclusion regarding correlation and causality of SCC in patients with breast implants can be drawn. There is an urgent need for national and international breast implant and breast cancer registries to obtain valid data on the incidence, pathogenesis and clinical presentation of rare tumour entities.

Nanosilver/DCOIT-containing surface coating effectively and constantly reduces microbial load in emergency room surfaces

BACKGROUND

Colonization of near-patient surfaces in hospitals plays an important role as a source of healthcare-associated infections. Routine disinfection methods only result in short-term elimination of pathogens.

AIM

To investigate the efficiency of a newly developed antimicrobial coating containing nanosilver in long-term reduction of bacterial burden in hospital surfaces to close the gap between routine disinfection cycles.

METHODS

In this prospective, double-blinded trial, frequently touched surfaces of a routinely used treatment room in an emergency unit of a level-I hospital were treated with a surface coating (nanosilver/DCOIT-coated surface, NCS) containing nanosilver particles and another organic biocidal agent (4,5-dichloro-2-octyl-4-isothiazolin-3-one, DCOIT), whereas surfaces of another room were treated with a coating missing both the nanosilver- and DCOIT-containing ingredient and served as control. Bacterial contamination of the surfaces was examined using contact plates and liquid-based swabs daily for a total trial duration of 90 days. After incubation, total microbial counts and species were assessed.

FINDINGS

In a total of 2880 antimicrobial samples, a significant reduction of the overall bacterial load was observed in the NCS room (median: 0.31 cfu/cm²; interquartile range: 0.00-1.13) compared with the control coated surfaces (0.69 cfu/cm²; 0.06-2.00; P < 0.001). The nanosilver- and DCOIT-containing surface coating reduced the relative risk of a critical bacterial load (defined as >5 cfu/cm²) by 60% (odds ratio 0.38, P < 0.001). No significant difference in species distribution was detected between NCS and control group.

CONCLUSION

Nanosilver-/DCOIT-containing surface coating has shown efficiency for sustainable reduction of bacterial load of frequently touched surfaces in a clinical setting.

Silver-coated versus uncoated locking plates in subjects with fractures of the distal tibia: a randomized, subject and observer-blinded, multi-center non-inferiority study

BACKGROUND

Antimicrobial coatings of implants are of interest to reduce infection rate in orthopedic surgery. Demonstration of clinical effectiveness of such coated implants to obtain market approval is challenging. The objective of this article is to define a design for a randomized controlled trial to evaluate the clinical performance of a silver-coating for locking plates for fracture treatment.

METHODS

The study design has to respect different criteria, such as feasibility, focus on overall complications, such as functional impairment, fracture healing, and particularly on infection rates. Distal tibia fractures were chosen due to the high prevalence of infections in this type of injuries, which warrants a particular benefit of antimicrobial prophylaxis and thus might allow to see a statistical trend in favor of the coated product. The study design was defined as a randomized, controlled, subject and observer-blinded, multi-center study in subjects with fractures of the distal tibia with a total of 226 patients. A number of 113 patients are planned for each of the two treatment arms with treatment of the fracture with a silver-coated device (first arm) or with an uncoated device (second arm). Inclusion criteria are closed fractures of the distal tibia according to the Tscherne-Oestern classification or open fractures of the distal tibia according to the Gustilo-Anderson classification in subjects older than 18 years. Primary outcome parameter is the Anticipated Adverse Device Effects (AADE) including all typical complications of this type of injury, such as functional impairment of the affected limb, non-union, and infections based on a non-inferiority study design. Also, silver-typical complications, such as argyria, are included. Secondary parameters are infection rates and fracture healing. Follow-up of patients includes five visits with clinical and X-ray evaluations with a follow-up time of 12 months.

DISCUSSION

Demonstration of clinical effectiveness of antimicrobial coatings of fracture fixation devices remains a challenge. Definition of a prospective randomized pre-market trial design and recruitment of clinical sites for such a study is possible. A confirmative proof of the expected clinical benefit in terms of reduction of device-related infections will be addressed with a prospective post-market clinical follow-up study in a second step due to the large sample size required.

TRIAL REGISTRATION

ClinicalTrials.gov NCT05260463. Registered on 02 March 2022.

Comparing the Time-Dependent Evolution of Microcirculation in Gracilis vs. ALT Flaps Using Laser-Doppler Flowmetry and Tissue-Spectrometry

Postoperative free flap monitoring is considered a key component of care after microsurgical reconstruction. To achieve successful flap salvage after surgical revision, early recognition of vascular compromise is required. The aim of this study was to assess and compare the time-dependent evolution of microcirculation in gracilis muscle (GM) and anterolateral thigh (ALT) flaps. This study included continuous measurements of blood flow (flow), hemoglobin oxygenation (SO2) and the relative amount of hemoglobin (rHb) using laser-doppler flowmetry and tissue-spectrometry (O2C, LEA Medizintechnik, Gießen, Germany) over a time-period of 72 h. Microcirculation was assessed in a total of 66 viable free flaps (GM n = 40; ALT n = 26). A statistically significant positive correlation between time post-anastomosis and microvascular flow was found for both GM and ALT flaps with rs = 0.384 (p < 0.001) and rs = 0.178 (p = 0.015), respectively. No significant positive or negative correlations between time post-anastomosis and SO2 were found for both GM and ALT flaps with rs = 0.052 (p = 0.387) and rs = −0.018 (p = 0.805), respectively. Overall, a significant negative correlation between time post-anastomosis and rHb was found for GM flaps with rs = −0.140 (p = 0.019). For ALT flaps, no significant positive or negative correlation was found with rs = −0.011 (p = 0.887). Microcirculation differs in different flap entities, and surgeons should be aware of these differences in order to correctly evaluate and classify the values of flow, SO2 and rHb obtained when using the O2C device for postoperative monitoring.

Microbiological and ultrastructural evaluation of bacteriophage 191219 against planktonic, intracellular and biofilm infection with Staphylococcus aureus

Infections of orthopaedic implants, such as fracture fixation devices and total-joint prostheses, are devastating complications. Staphylococcus aureus (S. aureus) is a predominant pathogen causing orthopaedic-implant biofilm infections that can also internalise and persist in osteoblasts, thus resisting antibiotic therapy. Bacteriophages are a promising alternative treatment approach. However, data on the activity of bacteriophages against S. aureus, especially during intracellular growth, and against in vivo biofilm formation on metals are scarce. Therefore, the present study evaluated the in vitro efficacy of S. aureus bacteriophage 191219, alone as well as in combination with gentamicin and rifampicin, to eradicate S. aureus strains in their planktonic stage, during biofilm formation and after internalisation into osteoblasts. Further, the invertebrate model organism Galleria mellonella was used to assess the activity of the bacteriophage against S. aureus biofilm on metal implants with and without antibiotics. Results demonstrated the in vitro efficacy of bacteriophage 191219 against planktonic S. aureus. The phage was also effective against in vitro S. aureus biofilm formation in a dose-dependent manner and against S. aureus internalised in an osteoblastic cell line. Transmission electron microscopy (TEM) analysis showed bacteriophages on S. aureus inside the osteoblasts, with the destruction of the intracellular bacteria and formation of new bacteriophages. For the Galleria mellonella infection model, single administration of phage 191219 failed to show an improvement in survival rate but appeared to show a not statistically significant enhanced effect with gentamicin or rifampicin. In summary, bacteriophages could be a potential adjuvant treatment strategy for patients with implant-associated biofilm infections.

Vertebral osteomyelitis is characterised by increased RANK/OPG and RANKL/OPG expression ratios in vertebral bodies and intervertebral discs

Vertebral osteomyelitis (VO) is an infection of the spine mainly caused by bacterial pathogens. The pathogenesis leading to destruction of intervertebral discs (IVDs) and adjacent vertebral bodies (VBs) is poorly described. The present study aimed at investigating the connection between infection and bone/disc metabolism in VO patients. 14 patients with VO (infection group) and 14 patients with burst fractures of the spine (fracture group; control) were included prospectively. Tissue biopsies from affected IVDs and adjacent VBs were analysed by RT-qPCR for mRNA-expression levels of 18 target genes including chemokines, adipokines and genes involved in bone metabolism. Most importantly, the receptor activator of NF-κB/osteoprotegerin (RANK/OPG) expression ratio was drastically elevated in both VBs and IVDs of the infection group. In parallel, expression of genes of the prostaglandin-E2-dependent prostanoid system was induced. Such genes regulate tissue degradation processes via the triad OPG/RANK/RANKL as well as via the chemokines IL-8 and CCL-20, whose expression was also found to be increased upon infection. The gene expression of the adipokine leptin, which promotes inflammatory tissue degradation, was higher in IVD tissue of the infection group, whereas the transcription of omentin and resistin genes, whose functions are largely unknown in the context of infectious diseases, was lower in infected VBs. In summary, similar expression patterns of pro-inflammatory cytokines and pro-osteoclastogenic factors were identified in VBs and IVDs of patients suffering from VO. This suggests that common immuno-metabolic pathways are involved in the mechanisms leading to tissue degradation in VBs and IVDs during VO.

New quantitative automated model to simulate bacterial dissemination in human tissue during irrigation of contaminated wounds

This study presents a simple and cost-effective model using microparticles to simulate the bacterial distribution pattern in soft tissue after low- and high-pressure irrigation. Silica coated iron microparticles [comparable diameter (1 µm) and weight (0.8333 pg) to Staphylococcus aureus] were applied to the surface of twenty fresh human muscle tissue samples in two amputated lower legs. Particle dissemination into deep tissue layers as an undesired side effect was investigated in four measuring fields as positive control (PC) as well as after performing pulsatile high-pressure (HP, 8 measuring fields) and low-pressure flushing (LP, 8 measuring fields). Five biopsies were taken out of each measuring field to get a total number of 100 biopsies. After histological and digital image processing, the specimens were analysed, and all incomplete sections were excluded. A special detection algorithm was parameterised using the open source bioimage analysis software QuPath. The application of this detection algorithm enabled automated counting and detection of the particles with a sensitivity of 95 % compared to manual counts. Statistical analysis revealed significant differences (p < 0.05) in our three different sample groups: HP (M = 1608, S = 302), LP (M = 2176, SD = 609) and PC (M = 4011, SD = 686). While both HP and LP flushing techniques are able to reduce the number of bacteria, a higher effectiveness is shown for HP irrigation. Nevertheless, a challenge for the validity of the study is the use of dead tissue and therefore a possible negative influence of high-pressure irrigation on tissue healing and further dispersion of particles cannot be evaluated.

[Patient consent for the TraumaRegistry DGU based on the GDPR-A challenge for the hospitals: status quo and solution strategies]

Gemäß der Datenschutz-Grundverordnung (EU-DSGVO, Mai 2018) werden anonymisierte Datensätze mit ausreichend hoher Datendichte als nachverfolgbar eingestuft und benötigen eine Einwilligungserklärung, wenn diese zu Forschungs- oder Qualitätskontrollzwecken zentral ausgewertet werden. Qualitätssicherung und weitere Steigerung der Versorgungsqualität sind im Rahmen der flächendeckenden Schwerstverletztenerhebung im Sinne der Versorgungsforschung allerdings nur mit einer annähernden Vollerhebung möglich. Die über 600 deutschen Kliniken, die am TraumaRegister DGU® teilnehmen, versuchen, von diesem speziellen Patientengut die Einverständniserklärungen zu erhalten. In der Studienklinik wurden über einen 12-Monats-Zeitraum hinweg die Rate an Einwilligungen und die Gründe für eine Ablehnung bzw. Nichteinholung evaluiert.

Bei Anwendung eines ressourcenintensiven Workflows speziell für die Patientenaufklärung und Einholung der TR-Einwilligungen wurden eine Zustimmungsquote der Patienten von 64,5 % und damit gleichzeitig eine Fehlquote von 35,5 % erfasst. Es konnten 98 von 276 potenziellen TraumaRegister-DGU®-Datensätzen nicht eingegeben werden und standen dementsprechend weder für die Qualitätskontrolle noch für die Polytraumaforschung zur Verfügung.

Um die Qualitätskontrolle und die weitere Verbesserung der Versorgungsqualität zu gewährleisten, ist eine annähernde Gesamterfassung des Patientenguts notwendig. Diese lässt sich durch die Notwendigkeit der Einwilligungserklärung jedoch nicht erreichen, wie unsere Studie zeigt. Somit plädieren wir dafür, dass die Möglichkeit geschaffen wird, den TraumaRegister-Datensatz ohne Einwilligung zu erheben, da dieser letztlich einen Regeldatensatz darstellt, vergleichbar mit dem §21-KHEntgG-Datensatz, jedoch im Gegensatz zu diesem pseudonymisiert.

Dental follicle cell differentiation towards periodontal ligament-like tissue in a self-assembly three-dimensional organoid model

Periodontitis remains an unsolved oral disease, prevalent worldwide and resulting in tooth loss due to dysfunction of the periodontal ligament (PDL), a tissue connecting the tooth root with the alveolar bone. A scaffold-free three-dimensional (3D) organoid model for in vitro tenogenesis/ligamentogeneis has already been described. As PDL tissue naturally arises from the dental follicle, the aim of this study was to investigate the ligamentogenic differentiation potential of dental follicle cells (DFCs) in vitro by employing this 3D model. Human primary DFCs were compared, in both two- and three-dimensions, to a previously published PDL- hTERT cell line. The 3D organoids were evaluated by haematoxylin and eosin, 4',6-diamidino-2-phenylindole and F-actin staining combined with detailed histomorphometric analyses of cell-row structure, angular deviation and cell density. Furthermore, the expression of 48 tendon/ligament- and multilineage-related genes was evaluated using quantitative polymerase chain reaction, followed by immunofluorescent analyses of collagen 1 and 3. The results showed that both cell types were successful in the formation of scaffold-free 3D organoids. DFC organoids were comparable to PDL-hTERT in terms of cell density; however, DFCs exhibited superior organoid morphology, cell-row organisation (p < 0.0001) and angular deviation (p < 0.0001). Interestingly, in 2 dimensions as well as in 3D, DFCs showed significantly higher levels of several ligament- related genes compared to the PDL-hTERT cell line. In conclusion, DFCs exhibited great potential to form PDL-like 3D organoids in vitro suggesting that this strategy can be further developed for functional PDL engineering.

Establishment of a clinically relevant large animal model to assess the healing of metaphyseal bone

Despite the high incidence of metaphyseal bone fractures in patients, the mechanisms underlying the healing processes are poorly understood due to the lack of suitable experimental animal models. Hence, the present study was conducted to establish and characterise a clinically relevant large-animal model for metaphyseal bone healing. Six female adult Merino sheep underwent full wedge-shaped osteotomy at the distal left femur metaphysis. The osteotomy was stabilised internally with a customised anatomical locking titanium plate that allowed immediate post-operative full-weight bearing. Bone healing was evaluated at 12 weeks post-fracture relative to the untouched right femur. Histological and quantitative micro-computed tomography results revealed an increased mineralised bone mass with a rich bone microarchitecture. New trabeculae healed by direct intramembranous ossification, without callus and cartilaginous tissue formation. Stiffness at the cortical and trabecular regions was comparable in both groups. Functional morphological analysis of the osteocyte lacunae revealed regularly arranged spherically shaped lacunae along with the canalicular network. Bone surface biochemical analysis using time-of-flight secondary-ion mass spectrometry showed high and homogeneously distributed levels of calcium and collagenous components. Ultrastructure imaging of the new trabeculae revealed a characteristic parallel arrangement of the collagen fibrils, evenly mineralised by the dense mineral substance. The specialised bone cells were also characterised by their unique structural features. Bone remodelling in the fractured femur was evident in the higher expression levels of prominent bone formation and resorption genes. In conclusion, the novel metaphyseal fracture model is beneficial for studying healing and treatment options for the enhancement of metaphyseal bone defects.

A metaphyseal fracture rat model for mechanistic studies of osteoporotic bone healing

Most osteoporotic fractures occur at metaphyseal regions of long bones. The present study proposed a clinically relevant animal model that satisfied: i) induction of osteoporosis, ii) unilateral complete osteotomy at metaphysis, iii) internal fixation. 6 months old female Sprague-Dawley rats (n = 64) were randomly divided into the ovariectomised-metaphyseal osteotomy (OVX, n = 32) and metaphyseal osteotomy (SHAM, n = 32) groups. The metaphyseal-osteotomy model was created with a plate-fixation of the osteotomy and assessed by X-ray, micro-computed tomography, histomorphometry and mechanical testing at weeks 1, 3 and 6. X-ray results showed complete healing of metaphyseal osteotomy at week 6. Histology showed 3 stages of metaphyseal healing. Stage 1 was characterised by fibrous tissue, consisting of disorganised orientation of collagen fibres, and infiltration of immune cells. At stage 2, a transitional zone consisting of maturing fibrous tissue and differentiating mesenchymal cells with early trabecular bone formation and disorganised woven bone were observed. During stage 3, cortical bone ends unified and woven bone underwent transformation to lamellar bone. OVX group healing was significantly delayed when compared to SHAM samples. The study demonstrated that healing of osteoporotic osteotomy at the metaphyseal region was delayed in terms of radiography, histomorphometry and mechanical strength. These quantitative evaluations, along with histological features, may provide key references for future studies. The animal model may provide additional clinical relevance as most osteoporotic fracture in humans occurs at metaphyseal regions.

STAT1 regulates macrophage number and phenotype and prevents renal fibrosis after ischemia-reperfusion injury

Renal ischemia-reperfusion injury (IRI) leads to acute kidney injury or delayed allograft function, which predisposes to fibrosis in the native kidney or kidney transplant. Here we investigated the role of the signal transducer and activator of transcription 1 (STAT1) in inflammatory responses following renal IRI. Our study showed that a subsequent stimulation of Janus-activated kinase 2/STAT1 and Toll-like receptor 4 pathways led to greater STAT1 activation followed by increased cytokine transcription compared with single-pathway stimulation in murine renal tubular cells. Moreover, we observed increased activation of STAT1 under hypoxic conditions. In vivo, STAT1^-/- mice displayed less acute tubular necrosis and decreased macrophage infiltration 24 h after renal ischemia. However, investigation of the healing phase (30 days after IRI) revealed significantly more fibrosis in STAT1^-/- than in wild-type kidneys. In addition, we demonstrated increased macrophage infiltration in STAT1^-/- kidneys. Flow cytometry analysis revealed that STAT1 deficiency drives an alternatively activated macrophage phenotype, which is associated with downregulated cluster of differentiation 80 expression, decreased intracellular reactive oxygen species production, and enhanced ability for phagocytosis. Furthermore, we detected immunohistochemically enhanced STAT1 expression in human renal allograft biopsies with no interstitial fibrosis/tubular atrophy (IF/TA) compared with specimens with severe IF/TA without specific etiology. Thus, STAT1 activation drives macrophages toward an alternatively activated phenotype and enhances fibrogenesis indicating a potential STAT1-driven protective mechanism in tissue repair after ischemic injury.

Successful Total Elbow Replacement after Septic Arthritis with Staphylococcus aureus- a Case Report and Review of the Literature

Septic arthritis of the elbow seems to be a contraindication for total elbow arthroplasty (TEA). We here describe a 65-year-old male, American Society of Anesthesiologists (ASA) class 3 - patient, with a severely destructed right elbow due to septic arthritis with Staphylococcus aureus. His treatment consisted of multiple irrigation and debridement procedures including resection of the distal humerus, soft tissue coverage by local rotational flap and the use of a gentamicin-vancomycin loaded PMMA spacer, i.v. and oral antibiotics. After eradication of infection, a constraint cemented TEA could then successfully be performed eight months after the initial surgery and twenty-five weeks after the last debridement procedure. Twenty-one months after the TEA, the patient remained infect free and shows excellent functional results: Disabilities of the Arm, Shoulder and Hand (DASH) score: 38.3, Broberg and Morrey score: 91/100, Mayo elbow score: 95/100. To the best of our knowledge this is the first case in the literature that demonstrates TEA after septic elbow arthritis with Staphylococcus aureus. Although TEA is known as a typical surgical procedure with a low volume in numbers and higher complication rates, such as elevated infection rates compared to other types of arthroplasty, septic arthritis with Staphylococcus aureuscan successfully be performed after eradication of the infection and targeted antibiotic therapy. Key words:total elbow arthroplasty, total elbow replacement, septic arthritis, Staphylococcus aureus.

Colloid, adhesive and release properties of nanoparticular ternary complexes between cationic and anionic polysaccharides and basic proteins like bone morphogenetic protein BMP-2

Herein we describe an interfacial local drug delivery system for bone morphogenetic protein 2 (BMP-2) based on coatings of polyelectrolyte complex (PEC) nanoparticles (NP). The application horizon is the functionalization of bone substituting materials (BSM) used for the therapy of systemic bone diseases. Nanoparticular ternary complexes of cationic and anionic polysaccharides and BMP-2 or two further model proteins, respectively, were prepared in dependence of the molar mixing ratio, pH value and of the cationic polysaccharide. As further proteins chymotrypsin (CHY) and papain (PAP) were selected, which served as model proteins for BMP-2 due to similar isoelectric points and molecular weights. As charged polysaccharides ethylenediamine modified cellulose (EDAC) and trimethylammonium modified cellulose (PQ10) were combined with cellulose sulphatesulfate (CS). Mixing diluted cationic and anionic polysaccharide and protein solutions according to a slight either anionic or cationic excess charge colloidal ternary dispersions formed, which were cast onto germanium model substrates by water evaporation. Dynamic light scattering (DLS) demonstrated, that these dispersions were colloidally stable for at least one week. Fourier Transform Infrared (FTIR) showed, that the cast protein loaded PEC NP coatings were irreversibly adhesive at the model substrate in contact to HEPES buffer and solely CHY, PAP and BMP-2 were released within long-term time scale. Advantageously, out of the three proteins BMP-2 showed the smallest initial burst and the slowest release kinetics and around 25% of the initial BMP-2 content were released within 14days. Released BMP-2 showed significant activity in the myoblast cells indicating the ability to regulate the formation of new bone. Therefore, BMP-2 loaded PEC NP are suggested as novel promising tool for the functionalization of BSM used for the therapy of systemic bone diseases.

[Primary results using the mini TightRope for revision surgery for painful proximalisation of the first metacarpal after trapezectomy for CMC-1-osteoarthritis]

AIM

The aim of the current study was to review the significance of the TightRope to suspend the first metacarpal in the case of a revision for patients with painful proximalisation after trapezectomy.

PATIENTS AND METHOD

After an average of 25.5 months (13-60) from initial operative treatment for rhizarthrosis, revision surgery was performed on 6 female patients with a mean age of 56 years, using a Mini TightRope. Before and after revision-surgery the pain level was measured, using the visual analogue scale (1-10) as was the level of strength in the fingertips. The overall result was documented according to the evaluation scale according to Buck-Gramcko. Directly after surgery as well as at the last follow-up exam, the degree of proximalisation of the first metacarpal was radiologically measured. The follow-up period was 13.7 months on average (4-31 months).

RESULTS

After revision surgery a decrease in pain level was detected, but no patient was completely pain-free. According to the visual analogue scale the pain level after surgery compared to preoperatively was: at rest at an average of 2.5 (1-4), preoperatively 3.3 (2-4); with mild load 3.5 (2-5), preoperatively 4.8 (4-6); and with high load 4.8 (3-7), preoperatively 7 (6-8). The level of strength in the fingertips was postoperatively measured at below 60% in 2 patients (preoperatively 5 patients), once between 60 and 79% (preoperatively 1 patient) and 3 times between 80 and 99%. With an average preoperative score of 11.7 (6-16) points according to Buck-Gramcko, an increase of 20.3 points could be achieved by performing the revision operation. This resulted in a score of 32 (14-44) out of 56 points. The measured distance between the distal scaphoid pole and the centre of the base of the first metacarpal was postoperatively at an average of 8.3 mm (5.6-11.4 mm). The final follow-up shows an average distance of 3.3 mm (2.8-4.3 mm). This is consistent with an average proximalisation of 5 mm. The Mini TightRope had to be removed three times. An additional operation had to be performed twice.

CONCLUSION

The use of the Mini TightRope for a suspension of the first metacarpal, in cases of a painful proximalisation after trapezectomy is a procedure that can cause an improvement for a certain percentage of patients. But a further proximalisation cannot be prevented by the use of the Mini TightRope.

Intracellular proliferation of S. aureus in osteoblasts and effects of rifampicin and gentamicin on S. aureus intracellular proliferation and survival

Staphylococcus aureus is the most clinically relevant pathogen regarding implant-associated bone infection and its capability to invade osteoblasts is well known. The aim of this study was to investigate firstly whether S. aureus is not only able to invade but also to proliferate within osteoblasts, secondly to delineate the mechanism of invasion and thirdly to clarify whether rifampicin or gentamicin can inhibit intracellular proliferation and survival of S. aureus. The SAOS-2 osteoblast-like cell line and human primary osteoblasts were infected with S. aureus EDCC5055 and S. aureus Rosenbach 1884. Both S. aureus strains were able to invade efficiently and to proliferate within human osteoblasts. Immunofluorescence microscopy showed intracellular invasion of S. aureus and transmission electron microscopy images could demonstrate bacterial division as a sign of intracellular proliferation as well as cytosolic bacterial persistence. Cytochalasin D, the major actin depolymerisation agent, was able to significantly reduce S. aureus invasion, suggesting that invasion was enabled by promoting actin rearrangement at the cell surface. 7.5 μg/mL of rifampicin was able to inhibit bacterial survival in SAOS-2 cells with almost complete elimination of bacteria after 4 h. Gentamicin could also kill intracellular S. aureus in a dose-dependent manner, an effect that was significantly lower than that observed using rifampicin. In conclusion, S. aureus is not only able to invade but also to proliferate in osteoblasts. Invasion seems to be associated with actin rearrangement at the cell surface. Rifampicin is effective in intracellular eradication of S. aureus whereas gentamicin only poorly eliminates intracellularly replicating bacteria.

Cholinergic nerve fibers in bone defects of a rat osteoporosis model and their regulation by implantation of bone substitution materials

OBJECTIVES

Bone is innervated by autonomic nervous system that consists of sympathetic and parasympathetic nerves that were recently identified in bone. Thus we asked whether parasympathetic nerves occur in bone defects and at the interface of substitution materials that were implanted for stabilization and improvement of healing in an osteoporosis animal model.

METHODS

Osteoporosis was induced in rats by ovariectomy and deficiency diet. A wedge-shaped osteotomy was performed in the metaphyseal area of femur. Eight different implants were inserted that were based on calcium phosphate cement, iron, silica-mineralized collagen, and modifications with strontium. Nerves were identified by immunohistochemistry with antibodies against vesicular acetylcholine transporter (VAChT), tyrosine hydroxylase (TH) and protein gene product 9.5 (PGP 9.5) as neuronal marker.

RESULTS

Cholinergic nerves identified with VAChT immunostaining were detected in defects filled with granulation tissue and in surrounding mast cells. No immunolabeling of cholinergic nerves was found after implantation. The general presence of nerves was reduced after implantation as shown by PGP 9.5. Sympathetic nerves identified by TH immunolabeling were increased in strontium functionalized materials.

CONCLUSION

Since cholinergic innervation was diminished after implantation a further increase in the compatibility of substitution materials to nerves could improve defect healing especially in osteoporotic bone.

[The operative treatment of a bowstring phenomenon of the thumb in childhood: case report and literature review]

INTRODUCTION

The operative treatment of a congenital trigger thumb comprises splitting the A1 pulley under conditions of hand surgery. One complication is cutting through the A2 pulley. In this case a bowstring phenomenon will result.

CASE REPORT

We report about the reconstruction of the A2 pulley by using a transosseous fixed tendon strip for a now 7-year-old boy with an impressive bowstring phenomenon with profound impairment of thumb function and power after surgery of a trigger thumb at the age of 2 years.

DISCUSSION

The iatrogenic splitting of the A2 pulley during the operative treatment of a congenital trigger thumb and the treatment of the resulting bowstring phenomenon are not sufficiently reflected at the literature. In adulthood, several different methods of pulley reconstruction are described.

CONCLUSION

In our opinion this technique is a safe and easy option to reconstruct the A2 pulley without expensive fibre anchors and enables a broad replacement without compromising extension tendons. Also outdated bowstring phenomenons are sufficiently stabilised. A good hand function with full preservation of finger flexibility and power is ensured as well.

[The operative treatment of a bowstring phenomenon of the thumb in childhood: case report and literature review]

INTRODUCTION

The operative treatment of a congenital trigger thumb comprises splitting the A1 pulley under conditions of hand surgery. One complication is cutting through the A2 pulley. In this case a bowstring phenomenon will result.

CASE REPORT

We report about the reconstruction of the A2 pulley by using a transosseous fixed tendon strip for a now 7-year-old boy with an impressive bowstring phenomenon with profound impairment of thumb function and power after surgery of a trigger thumb at the age of 2 years.

DISCUSSION

The iatrogenic splitting of the A2 pulley during the operative treatment of a congenital trigger thumb and the treatment of the resulting bowstring phenomenon are not sufficiently reflected at the literature. In adulthood, several different methods of pulley reconstruction are described.

CONCLUSION

In our opinion this technique is a safe and easy option to reconstruct the A2 pulley without expensive fibre anchors and enables a broad replacement without compromising extension tendons. Also outdated bowstring phenomenons are sufficiently stabilised. A good hand function with full preservation of finger flexibility and power is ensured as well.

[Ovariectomy and calcium/vitamin D2/D3 deficient diet as a model of osteoporosis in the spine of Sprague-Dawley rats]

BACKGROUND

Osteoporosis is a widespread disease characterised by low bone mass and structural deterioration of bone resulting in an increased susceptibility to fractures. Osteoporosis affects women more frequently than men; every second woman older than 50 years suffers from an osteoporotic fracture, frequently a vertebral fracture. The aim of this study was to induce osteoporosis in rats to establish an osteoporotic small-animal model that simulates the human pathology particularly in the spine. Therefore, bone density parameters, which are routinely determined in the spine of osteoporotic patients, were investigated by Dual-Energy X-ray Absorptiometry (DEXA).

MATERIALS AND METHODS

Fourteen-week-old female Sprague-Dawley rats (n = 50) were either sham-operated (control group: sham) or ovariectomised (experimental group). Ovariectomised rats were further divided into two groups; one received calcium/vitamin D2/D3 deficient diet (OVX + diet), and the other received subcutaneous steroid injections (dexamethasone 0.3 mg/kg body weight) twice a month (OVX + steroid). Rats were scanned by DEXA at three time points (Month = M, 0 M, 1 M and 3 M). DEXA measurement of the spine delivered T-value, Z-value, bone mineral content (BMC), and the scanned area. Fifteen female patients at an age of 57-72 years were scanned in 8-10 regions of the spine (150 measurements). T-values and Z-values were pre-calculated based on patient databases. Statistical analysis was performed using two-way ANOVA followed by Bonferroni correction, with significance considered at p < 0.05.

RESULTS

T-value and Z-value of both rat groups were compared with the patient data as well as with each others. Both treated rat groups revealed significantly lower T- and Z-values than controls. Despite the significant difference, the reference line (-2.5 for T-value and -1.5 for Z-value) was only reached by the OVX + diet group. On the other hand, the sham group showed an increase in BMC over time, while no change was seen in OVX + diet or OVX + steroid. Bone area demonstrated a significant increase up to M3. However, the increase in bone area within the OVX + diet group was notably higher than in both sham and OVX + steroid groups. Patients showed significantly lower T- and Z-values than sham and OVX + steroid but insignificant ones when compared with OVX + diet.

CONCLUSION

A reproducible vertebral osteoporosis can be generated in a rat model by combination of ovariectomy with administration of a calcium/vitamin D3 deficient diet. T- and Z-values of this experimental group mimicked values obtained from osteoporotic patients, reflecting a simulation of their pathology. Interestingly, the increase in bone area over time with the steady BMC results in lower mineral density (BMD) of the OVX + diet group. Therefore, this rat model presents a reliable experimental set-up that may serve as a tool to better understand and treat osteoporosis.

[Operative treatment of osseous pull out of the extensor tendon using a hook plate]

OBJECTIVE

Anatomical reposition and stabilization of dorsal distal phalanx fractures with a hook plate.

INDICATIONS

Dislocated mallet fractures type Doyle IVb with dislocation of the fragment by more than 2 mm and/or tilting of the fragment as well as dislocation of the dorsal distal phalanx fractures type Doyle IVc.

CONTRAINDICATIONS

Florid inflammation of and injuries to the soft tissues in the operation area.

SURGICAL TECHNIQUE

Dorsal approach to the distal interphalangeal joint (Y-, S-, H-shaped). Preparation of the fragment, cleaning the fracture gap, repositioning of the fragment, mounting of the plate, placing the screw. Controlling by image converter. Suture of the skin; tape.

POSTOPERATIVE MANAGEMENT

Stack splint for 4 weeks. After week 3, start with exercising of the distal interphalangeal joint within the splint. Physiotherapy is usually not required. Full exertion after 6-8 weeks is possible. The period of inability to work is dependent on the patient's occupation. Due to the danger of perforation and infection, it is recommended that the plate be removed after 3-6 months.

RESULTS

From February 2002 to September 2009, 77 mallet fractures type Doyle IVb and IVc were operatively stabilized with a hook plate. In a retrospective study, 59 patients were followed up at a mean interval of 38.3 (3-69) months after the operation. Wound healing problems or inflammation were not observed. Visible disturbances of nail growth were macroscopically seen in 11.9%. Results were very good in 35 patients (59.3%), good in 16 patients (27.1%), sufficient in 5 patients (8.5%), satisfying in 1 patient (1.7%), and insufficient in 2 patients (3.4%).

mRNA expression and protein distribution of fibronectin splice variants and high-molecular weight tenascin-C in different phases of human fracture healing

Fracture healing is a reparative physiological process, which proceeds in stages, each characterized by the predominant tissue in the fracture gap. The tissue matrix is continuously reorganized by cell migration, proliferation, and differentiation. Adhesive proteins such as fibronectin and tenascin transmit information between matrix and cells. As a result of alternative splicing of pre-RNA, EDA + fibronectin, EDB + fibronectin, and high-molecular weight (hm) tenascin-C are generated. By definition, EDB + fibronectin is an oncofetal protein because it is extremely rare in normal adult tissue and plasma, whereas it is expressed in fetal and tumor tissues and during wound healing. In this study, we for the first time describe EDA + fibronectin, EDB + fibronectin, and hm tenascin-C expression in human fracture gap tissue during various stages of differentiation. We demonstrate mRNA expression of all three splice variants in the initial fibrin matrix with upregulation in the enchondral ossification/osteoid and woven bone stages. Of all variants, EDA + fibronectin mRNA has the highest concentration in all stages. For the analysis, we used LightCycler-based relative mRNA quantification and immunohistochemistry. Our data demonstrate that EDA + fibronectin and hm tenascin-C show a diffuse distribution pattern in fracture gap connective tissue, while EDB + fibronectin is focally concentrated in osteoblastic cells at the margins of woven bone. EDA + fibronectin and hm tenascin represent markers for active granulation processes, whereas EDB + fibronectin is specific for cells forming the enchondral and osteoid matrix. The possibility of stimulating fracture healing by EDB + fibronectin-cytokine complexes should be tested in further investigations.

[Health-economic considerations for the use of BMP-2 for spinal surgery in Germany]

INTRODUCTION

BMP-2 can replace autogenous bone grafting in lumbar one-level anterior lumbar interbody fusions (ALIF). The current G-DRG system does not reimburse the upfront price of 2,970 euro per BMP-2 application for hospitals in Germany. The purpose of the current study was to create a health economic model to evaluate the financial savings for health care providers (hospitals) and health care payers (health care insurance) that can be achieved by the use of BMP-2 in spine surgery.

METHODS

A previously published pooled data analysis was used in which BMP-2 showed significant improvements in the treatment after ALIF surgery compared to autogenous bone grafting, including earlier return to work time and reduced revision rates. These medical findings were transformed into economic data based on the regulations of the German health system of 2005.

RESULTS

The significantly shorter return to work time under BMP-2 treatment generates important financial savings for health care insurances offsetting the upfront prize of 2,970 euro for BMP-2. Savings for hospitals are mainly related to shorter surgery time due to the absence of the bone grafting procedure and faster discharge of the patient.

CONCLUSIONS

The combination of improved medical outcome by BMP-2 treatment for the patient and net savings for the entire health care system in Germany represents a "dominant" strategy from a health economic perspective. This implicates that BMP-2 in ALIF procedures is to be recommended from a health economic point of view for the German health care system.

[School accidents--an epidemiological assessment of injury types and treatment effort]

Children and adolescents spend up to 50% of their time at school. The purpose of this study was to assess injury patterns with their treatment of school accidents in a Trauma Service of a German University Hospital and to compare these data to the literature. All school accidents from 01.07.1999 to 30.06.2004 were statistically analysed in a retrospective manner by chart review. There were 1399 school accidents treated in our department. Average age of the injured children was 11.8 years with a boy:girl ratio of 3:2. Almost 40% of the injuries occurred during school sport. The most frequently injured region was the upper extremity including the hand (36.8%). Distortion and contusion were the most frequent diagnoses of all injuries. 16% of the cases had to be treated surgically and/or under general anaesthesia and also a total of 16% of the patients had to be admitted to the hospital. It can be concluded for school facilities that special attention has to be paid during school sports activity and breaks because they account for most accidents. Traffic education may reduce severe injuries. For diagnosis and treatment of school accidents specific knowledge of the growing longbones of the upper extremity and the hand is important.

[Cost-benefit analysis of the use of rhBMP-2 in open tibial fractures: savings from a health insurer's perspective]

BACKGROUND AND PURPOSE

The purpose of the current study was to evaluate savings from the use of recombinant human bone morphogenetic protein-2 (rhBMP-2) in open tibia fractures by faster fracture healing and reduction of secondary treatment costs from a health insurance perspective for Germany and to compare them to the upfront price of 2900 EUR of rhBMP-2.

METHODS

Raw data from a previously published study (BESTT study) were used to conduct an economic calculation for secondary treatment costs for each patient from the standard care group and the 1.5 mg/ml rhBMP-2 group based on G-DRG 2005 prices from a health insurer's perspective for an observation period of 1 year for Germany.

RESULTS

The use of rhBMP-2 leads to savings of 5697 EUR and 3183 EUR per patient for Gustilo-Anderson grade IIIB and all grade IIIA and B injuries, respectively. These savings offset the upfront price of 2900 EUR of rhBMP-2 and, therefore, net savings of 2797 EUR and 283 EUR for grade IIIB and all grade IIIA and B injuries can be achieved, respectively. These savings are mainly due to reduced sickness payments because of faster fracture healing in the rhBMP-2 group.

CONCLUSIONS

The current study shows that the use of rhBMP-2 in Gustilo-Anderson grade IIIA and B open fractures leads--besides the better medical outcome for patients as shown previously in the BESTT study--to net savings from a health insurer's perspective.

Economic considerations for the use of recombinant human bone morphogenetic protein-2 in open tibial fractures in Europe: the German model

The addition of recombinant human bone morphogenetic protein (rhBMP-2) to the standard of care, consisting of soft tissue management and intramedullary nailing, in the BMP-2 Evaluation in Surgery for Tibial Trauma (BESTT) study led to a significantly better outcome for the patient. Reductions in fracture healing time, secondary interventions for delayed fracture healing and infection rates were observed with 1.50 mg/mL rhBMP-2 compared with the standard of care alone. In Germany the approximate cost of applying one dose of recombinant human bone morphogenetic protein-2 (rhBMP-2) to an open tibial fracture is euro2970. The current German-Diagnosis-Related Group reimbursement system provides one flat rate per hospital stay or treatment case, and does not take into account the costs of rhBMP-2 application. Therefore there is no reimbursement for the price of rhBMP-2 for hospitals by health insurance companies. However, the above mentioned improvements in medical outcome could lead to important savings for health care systems, particularly for health insurance companies. A sound economic model to assess the cost-effectiveness and budget impact of rhBMP-2 is required. Using medical data from the BESTT study the differences in fracture healing time, in reduction of secondary interventions for fracture healing and infection treatment can be transferred into economic savings. It is anticipated that the overall savings that can be achieved by rhBMP-2 treatment in open tibia fractures, offset the upfront price of rhBMP-2 and lead to net savings for health insurance companies.

Die Arterien des Humerus und deren Bedeutung für die Frakturbehandlung

BACKGROUND

The purpose of the current work was to study the arterial blood supply of the humerus to evaluate impairments of the blood supply after humeral fractures and different methods of fracture treatment.

METHODS

Arterial blood supply of the humerus was studied by corrosion injection technique in 6 cadaver preparations and is compared with the existing literature.

RESULTS

Humeral head arteries originate from the circumflex humeral arteries. The major vessel enters the greater tubercle. Another group of vessels accesses the head from medially. The nutrient artery for the shaft enters into the medial third of the shaft. At the distal humerus there are multiple anastomoses with penetrating branches into both condyles and proximal to the radial, coronoid, and olecranon fossae.

CONCLUSIONS

Fragments of a proximal humeral fracture usually have an independent blood supply. The medial vessels to the head gain high importance in fractures of the anatomical neck. The nutrient artery lies regularly medial to the humeral mid-shaft and is at risk at open reduction of this region. The abundant vessels at the entire distal humerus ensure sufficient vascularization of the fragments after fracture.

Regulation of mesenchymal stem cell and chondrocyte differentiation by MIA

Melanoma inhibitory activity (MIA), also referred to as cartilage-derived retinoic acid-sensitive protein (CD-RAP), an 11-kDa secreted protein, is mainly expressed in cartilaginous tissue during embryogenesis and adulthood. Currently, the function of MIA in cartilage tissue is not understood. Here, we describe that MIA acts as a chemotactic factor on the mesenchymal stem cell line C3H10T1/2, stimulating cell migration significantly at concentrations from 0.24 to 240 ng/ml, while inhibiting cell migration at higher doses of 2.4 microg/ml. When analyzing the role of MIA during differentiation processes, we show that MIA by itself is not capable to induce the differentiation of murine or human mesenchymal stem cells. However, MIA influences the action of bone morphogenetic protein (BMP)-2 and transforming growth factor (TGF)-beta 3 during mesenchymal stem cell differentiation, supporting the chondrogenic phenotype while inhibiting osteogenic differentiation. Quantitative RT-PCR analysis revealed the up-regulation of the cartilage markers MIA, collagen type II and aggrecan in human mesenchymal stem cell (HMSC) cultures differentiated in the presence of MIA and TGF-beta 3 or BMP-2 when compared to HMSC cultures differentiated in the presence of TGF-beta 3 or BMP-2 alone. Further, MIA down-regulates gene expression of osteopontin and osteocalcin in BMP-2 treated HMSC cultures inhibiting the osteogenic potential of BMP-2. In the case of human primary chondrocytes MIA stimulates extracellular matrix deposition, increasing the glycosaminoglycan content. Therefore, we postulate that MIA is an important regulator during chondrogenic differentiation and maintenance of cartilage.

The arteries of the humeral head and their relevance in fracture treatment

Bone vascularisation has gained increased interest in relation to the blood supply of bone fragments during treatment of fractures. In the current study the pattern of vascular supply of the proximal humerus was studied in six cadavers by the corrosion technique. Furthermore, the effect of fractures on the vascular supply was also investigated. In all preparations the intraosseous arteries of the humeral head arose from the circumflex arteries, which surrounded the humerus and dispatched branches towards the proximal end. The main vessel was the branch of the anterior circumflex artery, penetrating the major tubercle in six of six cases. Due to the intraosseous arch shape of this vessel it is referred to as the arcuate artery. Besides other smaller vessels, there was also a vascular network arising from the posterior circumflex artery. Their branches penetrated medially at the cartilage bone interface in five of six preparations. The medial bone arteries appear to gain distinctive importance in humeral head fractures by their impact on the vascularisation of the fracture fragments. After disruption of the arterial supply from the arcuate artery, the vascularisation of the head fragments is most likely ensured by this group of vessels. Therefore, necessary repositioning manoeuvres during open reduction of the fracture should be conducted with care in order to preserve these arteries.

Plasma transglutaminase factor XIII induces microvessel ingrowth into biodegradable hydroxyapatite implants in rats

Coagulation factor XIII is a member of the transglutaminase-family. Transgluaminases cross-link either fibrin monomers in blood coagulation or extracellular proteins in extracellular matrix formation. In early stages of bone healing migration and proliferation of endothelial cells lead to formation of new vessels. The aim of this study was to investigate the angiogenetic activity of plasma factor XIII in bone defects filled with nanoparticulate hydroxyapatite paste. A critical size defect was created in the tibial head of rats which was not filled in group I. In group II the defect was filled with hydroxyapatite paste, and in group III with hydroxyapatite paste enriched with factor XIII. Ten days after surgery angiogenesis in the defects was assessed using immunohistochemistry and confocal laser scanning microscopy. Ac16 antibody was used to detect activation of factor XIII into factor XIIIA. In defects without biomaterial (group I) vessel-rich connective tissue and diffuse distribution of capillaries was observed. In defects filled with pure hydroxyapatite (group II) formation of capillaries was limited to the host bone-hydroxyapatite interface. In contrast, addition of plasma factor XIII to hydroxyapatite (group III) stimulated formation of vessels within the biomaterial. The current study reveals that factor XIII can improve angiogenesis in hydroxyapatite.

Neurovaskuläre Lappenplastiken zum Verschluss problematischer Weichteildefekte am Unterschenkel

AIM OF THE STUDY

Soft tissue covering on the lower leg is a difficult challenge. A plastic surgical method for covering of these soft tissue defects is presented.

PATIENTS AND METHODS

From May 1997 until May 2003 36 patients were treated using neurovascular flaps. Above the sural or the saphenous nerve an adipo-facial flap is dissected, rotated into the defect and fixed without tension. Wound closure of the donor-site defect is done primarily or by mesh-graft.

RESULTS

In 35 cases the flap healed without functional impairment. Primary healing was achieved in 30 patients. In 5 cases partial loss of the skin island was registered, whereby subcutaneous tissue remained vital. Revision by mesh-graft transplantation led to successful healing in these patients. In only one patient necrosis of the flap was seen.

CONCLUSION

Neurovascular flaps usually result in reliable and complete healing of soft tissue defects of the lower extremity.

[Nanoparticulate silver. A new antimicrobial substance for bone cement]

BACKGROUND

Multiresistant bacteria have become an important problem in prosthetic joint infections. Their frequent resistance against gentamicin, which is commonly used in antibiotic-loaded bone cements, makes a new prophylaxis necessary.

METHODS

PMMA-cement was loaded with 1% nanoparticulate silver and its antibacterial activity tested in vitro against gentamicin-resistant MRSE and MRSA strains as well as being compared to the activity of plain and gentamicin-loaded bone cements. A quantitative elution testing was also done to study the potentially cytotoxic effects of NanoSilver cement.

RESULTS

Unloaded and PMMA-cement loaded with 2% gentamicin did not exhibit any antibacterial activity against MRSE and MRSA. At 1%, NanoSilver cement completely inhibited the proliferation of MRSA and MRSE. NanoSilver bone cement did not show any significant differences compared to the non-toxic control group.

CONCLUSIONS

If these promising in vitro results can be confirmed in vivo, NanoSilver bone cement may be of considerable value in total joint arthroplasty.

Expression of EDA+ and EDB+ fibronectin splice variants in bone

The extracellular matrix component fibronectin (fn) has fundamental functions in cell attachment, differentiation, proliferation, and migration. Isoforms of cellular fibronectin, named EDA+ fibronectin or embryonal EDB+ fibronectin, are generated by alternative splicing of its mRNA precursors. Little is known about the expression of EDA+ and EDB+ fibronectin splice variants in human bone. The aim of this study was to investigate the expression pattern of fibronectin splice variants in bone cell lines and in different human bone tissue samples (mature bone, early stages of fracture healing, hypotrophic nonunion, osteosarcoma). Analysis was done by immunostaining with recombinant and monoclonal antibodies, qualitative RT-PCR and LightCycler-based real-time quantitative RT-PCR assay. In osteoblast and osteosarcoma cell lines, abundant expression of EDA+ and EDB+ fibronectin was found in immunocytochemistry. High transcription levels of both splice variants mRNA were seen in quantitative RT-PCR in osteosarcoma cell lines. In mature bone, EDA+ and EDB+ were not detectable in immunohistochemistry. Transcription of mRNA in both splice variants was absent in these samples. Early stages of fracture healing and osteosarcoma cell samples exhibited extensive staining for EDA+ and EDB+ fibronectin, and high mRNA levels were found. Both osteosarcoma and bone fracture healing tissue expressed high mRNA levels of the fibronectin splice variants independent of benign or malignant behavior. Low level of EDA+ fibronectin mRNA transcription and focal immunohistochemical staining of EDA+ fibronectin was found in hypotrophic nonunions, whereas EDB+ fibronectin was not detected by immunohistochemistry and qualitative or quantitative PCR. EDA+ fibronectin was found in granulation tissue-forming processes in bone independent from bone-forming activity. EDB+ fibronectin was seen only in high-turnover new osteoid-forming processes like early stages of fracture healing and osteosarcoma and was absent in low-turnover processes like mature bone and hypotrophic nonunion. Both EDA+ and EDB+ fibronectin mark active processes in bone without differentiation between malignant or benign activity. In conclusion, EDA+ and EDB+ fibronectin splice variants are strong markers for active fibrogenetic and osteoid-forming processes in human bones.

Dorsal transscaphoid-transtriquetral perilunate dislocation in pseudarthrosis of the scaphoid

A patient reported that he sustained a minor fall on the outstretched hand in hyperextension, pronation, and in ulnar deviation. Initial radiographs suggested dorsal transscaphoid-transtriquetral perilunate dislocation. Traditionally, however, this injury is the result of a high-energy impact. A CT scan obtained after closed reduction of the dislocation revealed not only a fresh fracture of the triquetrum but also two corticalized fragments of the scaphoid. A former major fall on this hand and a normal scaphoid of the other hand made pseudarthrosis more likely than scaphoid bipartition. Arthrography revealed intact lunotriquetral and scapholunate ligaments, precluding the possibility of preexisting ligamentous instability. Pseudarthrosis of the scaphoid with a loss of scaphoid function as a mechanical tie-rod of the carpus is most likely responsible for this complex injury. This is the first clinical study that shows that single scaphoid discontinuity without preexisting ligamentous carpal instability may lead to complex perilunar dislocation in minor trauma.

Die Problematik der Hoffa-Fraktur

To study the outcome in Hoffa fractures regarding the type of fracture, concomitant injuries, and different treatments. From January 1996 until December 2002, 7 Hoffa fractures (6 patients) from a total of 79 distal femoral fractures were treated in the Department of Trauma Surgery, University Hospital of Giessen. The results were evaluated by Neer's score. For the evaluation of postoperative vascularization of the distal femur, clinical and radiological findings were compared with anatomical studies of the bone arteries by corrosion preparations. Fracture consolidation was seen in all cases. Patients with an isolated Hoffa fracture achieved a score of 89.0 (82-97) according to Neer. One patient suffering initially from nonunion achieved 68 points after bone union. One polytraumatized patient with bilateral Hoffa fracture achieved a satisfying result (score value of 72) and a bad result (score value of 38). Multiple small nutrient arteries of the distal femur originate from the "rete articulare genus." They can be expected to ensure the arterial blood supply. Hoffa fracture is a very rare injury. In our patients, careful surgical treatment with open reduction and safe screw fixation yielded good to very good results.

[Intraligamentous suture of a scapholunar ligament lesion in a 9-year-old child]

Scapholunate dissociation is a well-known injury in adult patients. In pediatric patients, repair of this injury in the skeletally immature carpus has been previously reported. However, in none of these case studies is single ligamentous suture performed. We report a case of scapholunate dissociation in a 9-year-old boy after an initial Salter I injury of the distal radius. After 6 weeks of wrist immobilization, arthroscopy was performed due to persisting pain over the scapholunate gap, a positive Watson sign, and limited range of motion. This arthroscopy revealed intraligamentous rupture of the scapholunate ligament. Suture repair of the scapholunate ligament was performed. The suture was protected by a temporary K-wire arthrodesis for 8 weeks. One year after removal of the K-wire, the patient is completely free of symptoms and resumes all sport activities.

[The BEHAC nail--a new intramedullary implant for managing 2-stage fractures of the humerus]

The BEHAC-nail is a new implant for the treatment of complex humeral fractures, particularly for segmental fractures. It is an elastic intramedullary implant that is inserted retrograde into the distal humerus. The special feature of this nail is its proximal "loop design" which reduces the implant penetration at the proximal fixation site in the subchondral area of the humeral head in comparison to implants with tips such as Rush pins or Hackethal's nails. Thus, the risk of nail migration and perforation of the humeral head is less with the BEHAC-nail than with other nails. Another advantage of the "loop design" is that the humeral head fragment can be fixed adequately. Even short proximal fragments can be stabilized with this design. In contrast a short humeral head fragment cannot be held with implants like the UHN, HVN or Seidel's nail. The BEHAC-nail is a useful implant for segmental fractures of the humerus.