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The (patho)physiological function of the sphingolipids ceramide-1-phosphate (C1P), sphingosine-1-phosphate (S1P), and sphingosylphosphorylcholine (SPC) in articular joints during osteoarthritis (OA) is largely unknown. Therefore, we investigated the influence of these lipids on protein expression by fibroblast-like synoviocytes (FLSs) from OA knees. Cultured human FLSs (n = 7) were treated with 1 of 3 lipid species-C1P, S1P, or SPC-IL-1ß, or with vehicle. The expression of individual proteins was determined by tandem mass tag peptide labeling followed by high-resolution electrospray ionization (ESI) mass spectrometry after liquid chromatographic separation (LC-MS/MS/MS). The mRNA levels of selected proteins were analyzed using RT-PCR. The 3sphingolipids were quantified in the SF of 18 OA patients using LC-MS/MS. A total of 4930 proteins were determined using multiplex MS, of which 136, 9, 1, and 0 were regulated both reproducibly and significantly by IL-1ß, C1P, S1P, and SPC, respectively. In the presence of IL-1ß, all 3 sphingolipids exerted ancillary effects. Only low SF levels of C1P and SPC were found. In conclusion, the 3 lipid species regulated proteins that have not been described in OA. Our results indicate that charged multivesicular body protein 1b, metal cation symporter ZIP14, glutamine-fructose-6-P transaminase, metallothionein-1F and -2A, ferritin, and prosaposin are particularly interesting proteins due to their potential to affect inflammatory, anabolic, catabolic, and apoptotic mechanisms.
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Ceramidas , Fibroblastos , Lisofosfolípidos , Proteómica , Esfingosina , Sinoviocitos , Humanos , Sinoviocitos/metabolismo , Sinoviocitos/patología , Lisofosfolípidos/metabolismo , Esfingosina/análogos & derivados , Esfingosina/metabolismo , Proteómica/métodos , Fibroblastos/metabolismo , Ceramidas/metabolismo , Esfingolípidos/metabolismo , Femenino , Células Cultivadas , Masculino , Anciano , Interleucina-1beta/metabolismo , Espectrometría de Masas en Tándem , Persona de Mediana Edad , Osteoartritis/metabolismo , Osteoartritis/patología , Osteoartritis/genética , Osteoartritis de la Rodilla/metabolismo , Osteoartritis de la Rodilla/patología , Osteoartritis de la Rodilla/genética , Fosforilcolina/análogos & derivadosRESUMEN
Introduction: Short stem prostheses were originally designed for younger and more active patients. In recent years, they have been increasingly offered to older patients. This study evaluates the mid-to long-term survival of a short stem prosthesis and the changes in periprosthetic bone density following implantation of a cementless short hip stem in patients over 60 years of age. Methods: 118 patients aged over 60 received short stem prostheses. Clinical examination included Harris Hip Score (HHS) and Hip Disability and Osteoarthritis Outcome Score (HOOS). 93 patients were followed clinically for at least five years. 53 patients underwent dual-energy x-ray absorptiometry (DXA) and radiographic evaluation. Follow-up intervals were preoperative and postoperative (t0), at approximately six months (t1), at approximately two years (t2), and at approximately five years or later (t3). Results: Over a mean 6.7-year observation period for all 118 patients, one stem revision occurred due to a traumatic periprosthetic stem fracture. The five-year survival rate for the endpoint survival of the Metha® stem in 95 at-risk patients is 99.2%. HHS improved significantly from t0 55.3 ± 11.5 (range 30-79) to t3 95.3 ± 8.6 (range 57-100) at a mean of 8.0 years (p < 0.001). HOOS improved significantly in each subscale (p < 0.001). Bone mineral density (BMD) was available for review in 53 patients after a mean of 7.1 years. BMD increased from t0 to t3 in region of interest (ROI) 3 (+0.4%) and ROI 6 (+2.9%) and decreased in ROI 1 (-10.3%), ROI 2 (-9.8%), ROI 4 (-5.3%), ROI 5 (-3.4%) and ROI 7 (-23.1%). Conclusions: The evaluated short stem prosthesis shows a remarkably high survival rate in elderly patients, accompanied by excellent clinical results. Load transfer measurements show a metaphyseal-diaphyseal pattern with a trend towards increased diaphyseal transfer over the period observed.
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BACKGROUND: The departure of young habilitated colleagues from their university careers reflects, on the one hand, a move away from university medicine per se and, on the other, an unwillingness to take on university management positions. In addition to the question of "How do I qualify for these positions?", the question of "Why should I aspire to such a position?" is increasingly taking centre stage when less expensive alternatives are available. In addition, there is uncertainty about the extent to which one's own achievements and qualities are sufficient to distinguish oneself clinically and scientifically in the course of one's career and thereby recommend oneself for management positions. AIMS: This is where the KUOU's Excellence Academy comes in, with the aim of identifying young colleagues with high potential for university leadership positions at an early stage, encouraging them to get to know each other, and focusing the attention and visibility of the university locations and the associated appreciation on the members of the Academy. The focus here is on ensuring that excellent colleagues benefit from the many years of experience of the members of the KUOU, receive feedback on their clinical and scientific achievements and are supported in their university career in the form of mentoring. CONCLUSION: The large number of 22 very good applications, of which 12 candidates were accepted, confirms our belief that there are excellently qualified colleagues at our sites, who are ready to take on responsibility in the future in the triad of research, teaching and patient care.
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Ortopedia , Humanos , Academias e Institutos , Cirugía de Cuidados Intensivos , Docentes Médicos , Traumatología/educación , UniversidadesRESUMEN
Introduction: In order to improve the anchorage behavior of short hip stems, this development project aims at designing a short hip stem concept that preserves the femoral neck and minimizes interference with the physiological stress distribution of the femur. The new design will be evaluated according to ISO 7206-4 which is the standard for testing Implants for surgery. Methods: Basic CAD models based on an established short stem prosthesis were created and evaluated using finite element analysis. The best design was further developed to achieve a more deformable stem while maintaining stability. The model was validated through in vitro testing. Results: The "H-Beam" short stem showed a higher degree of deformation of approximately 142-144% compared to the established short stem. The FE model had a relative error of 0.98% and 1.07% compared to the in vitro tests. An operating procedure was outlined for this new short stem design. Discussion: The FE model is deemed valid due to small differences in comparison to in vitro testing. The short-stem prosthesis is more flexible and can be easily adapted to individual anatomy during surgery. The prosthesis length is similar to conventional prostheses, but the new stem design could allow better and faster osteointegration while preserving the cancellous bone structure.
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Early aseptic loosening following primary total knee arthroplasty related to several factors might appear at the interface implant-cement or cement-bone. A standardized in vitro model might provide information on the relevance of single variable parameter of cementation including technique and cement respectively bone structure on fixation strength. Micromotion measurement using different directions of load should detect the primary stability of the interfaces. An open-cell rigid foam model was used for cementation of PFC-Sigma tibial trays with Palacos®. Pins were applied to the model for continuous non-destructive measurement. Relative micromotions for rotation, valgus-varus and extension flexion stress were detected at the interfaces as well as cement penetration was measured. The reproducibility of the measurement could be shown for all interfaces in extension-flexion movements. For rotation a negative trend was shown for the interface cement-prosthesis and cement-bone concerning varus-valgus stress reflecting varying surgical cementation technique. More micromotion related to extension-flexion force might reflect the design of the implant. Measurement of relative micromotion and cement distribution appear accurate to detect small differences of movement at different interfaces of cemented tibial implants and the results are reproducible for most parameter. An increased number of specimens should achieve statistical relevance for all measurements.
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Artroplastia de Reemplazo de Rodilla , Miembros Artificiales , Reproducibilidad de los Resultados , Cementos para Huesos , Clavos OrtopédicosRESUMEN
BACKGROUND: Preparing the medullary space of the femur aims to create an ideal form-fitting of cementless implants to provide sufficient initial stability, which is crucial for osseous integration, ensuring good long-term results. Hammering the implant into the proximal femur creates a press-fit anchoring of the endoprosthesis in the medullary space. Implanting the optimal size of the shaft for best fitting should avoid damage to the bone. Modified acoustic signals in connection with implantation are being detected by surgeons and might be related to the primary stability of the implant. METHODS: This study aims to explore the relationship between frequency sound patterns and the change in stem stability. For this purpose, n = 32 Metha® short stems were implanted in a clinical setting by the same surgeon. During implantation, the sounds were recorded. To define a change in the acoustic system response during the operation, the individual blows of the implantation sequence were correlated with one another. FINDINGS: An algorithm was able to subdivide through sound analysis two groups of hammer blows (area 1 and area 2) since the characteristics of these groups showed significant differences within the frequency range of 100 Hz to 24 kHz. The edge between both groups, detected by the algorithm, was validated with expert surgeons' classifications of the same data. INTERPRETATION: In conclusion, monitoring, the hammer blows sound might allow quantification of the primary stability of the implant. Sound analysis including patient parameters and a classification algorithm could provide a precise characterization of implant stability.
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Artroplastia de Reemplazo de Cadera , Prótesis de Cadera , Humanos , Artroplastia de Reemplazo de Cadera/métodos , Diseño de Prótesis , Fémur/cirugía , AcústicaRESUMEN
Synovial fluid (SF) from human knee joints with osteoarthritis (OA) has elevated levels of lysophosphatidylcholine (LPC) species, but their functional role is not well understood. This in vitro study was designed to test the hypothesis that various LPCs found elevated in OA SF and their metabolites, lysophosphatidic acids (LPAs), modulate the abundance of proteins and phospholipids (PLs) in human fibroblast-like synoviocytes (FLSs), with even minute chemical variations in lysophospholipids determining the extent of regulation. Cultured FLSs (n = 5-7) were treated with one of the LPC species, LPA species, IL-1ß, or a vehicle. Tandem mass tag peptide labeling coupled with LC-MS/MS/MS was performed to quantify proteins. The expression of mRNA from regulated proteins was analyzed using RT-PCR. PL synthesis was determined via ESI-MS/MS, and the release of radiolabeled PLs was determined by means of liquid scintillation counting. In total, 3960 proteins were quantified using multiplexed MS, of which 119, 8, and 3 were significantly and reproducibly regulated by IL-1ß, LPC 16:0, and LPC 18:0, respectively. LPC 16:0 significantly inhibited the release of PLs and the synthesis of phosphatidylcholine, LPC, and sphingomyelin. Neither LPC metabolite-LPA 16:0 nor LPA 18:0-had any reproducible effect on the levels of each protein. In conclusion, small chemical variations in LPC species can result in the significantly altered expression and secretion of proteins and PLs from FLSs. IL-1ß influenced all proteins that were reproducibly regulated by LPC 16:0. LPC species are likely to modulate FLS protein expression only in more advanced OA stages with low IL-1ß levels. None of the eight proteins being significantly regulated by LPC 16:0 have been previously reported in OA. However, our in vitro findings show that the CD81 antigen, calumenin, and B4E2C1 are promising candidates for further study, focusing in particular on their potential ability to modulate inflammatory and catabolic mechanisms.
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Osteoartritis , Sinoviocitos , Humanos , Sinoviocitos/metabolismo , Espectrometría de Masas en Tándem , Lipidómica , Proteómica , Cromatografía Liquida , Lisofosfolípidos/metabolismo , Osteoartritis/metabolismo , Lisofosfatidilcolinas/metabolismo , Fibroblastos/metabolismoRESUMEN
INTRODUCTION: Self-monitoring is crucial to work progressively with a high-quality standard. A retrospective analysis is a valuable tool for studying the postoperative outcome of a prosthesis and for evaluating the learning process for the surgeon. MATERIALS AND METHODS: The learning process of one surgeon was analysed in 133 cases of hip arthroplasty. These were divided into seven groups representing the surgical years 2008-2014. Over the course of 3 postoperative years, a total of 655 radiographs were analysed at regarding three radiological quality parameters (centrum-collum-diaphyseal angle (CCD angle), intramedullary fit&fill ratio (FFR), and migration) and ancillary outcome parameters (Harris Hip Score (HHS), blood loss, operating time, and complications). This period was divided into five times: 1st-day post-op, 6 M, 12 M, 24 M, and 36 M. Bivariate Spearman's correlation analysis and pairwise comparisons were performed. RESULTS: The total collective achieved a proximal FFR of over 0.8. The distal prosthesis tip migrated and was located on the lateral cortex within the first months. The CCD angle initially showed a variation with a subsequent constant course. The HHS showed a significant increase (p < 0.001) to over 90 points postoperatively. Over time, the operating time and blood loss decreased. Intraoperative complications existed only at the beginning of the learning phase. A learning curve effect can be determined for almost all parameters by comparing the subject groups. CONCLUSIONS: Operative expertise was shown to gain through a learning curve, whereby postoperative results corresponded to the system philosophy of the short hip stem prosthesis. The distal FFR and the distal lateral distance could represent the principle of the prosthesis, which overall could be an interesting approach for verification of a new parameter.
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Artroplastia de Reemplazo de Cadera , Prótesis de Cadera , Humanos , Artroplastia de Reemplazo de Cadera/métodos , Estudios Retrospectivos , Rayos X , Curva de Aprendizaje , Resultado del Tratamiento , Diseño de PrótesisRESUMEN
Background: Currently, the influence of muscle traction on the postoperative stability of humeral prostheses is not adequately researched. This study analyzed the prosthesis' stability in vitro during muscle traction considering different bone defect sizes. Methods: The reverse humeral prosthesis "AEQUALIS™ ADJUSTABLE REVERSED" (Stryker) was implanted using press-fit into ten bones with a length of 200 mm and 160 mm. Subsequently, the models were torqued in 30 cycles using a universal testing machine (2 Nm - 6 Nm) and loaded axially to simulate muscle traction. The axial weight increased from 7.7 kg (pure muscle traction) over 40 kg (45-degree abduction) to 69.3 kg (90-degree abduction). The prosthesis' relative micromotion was simultaneously measured at three different measurement heights using high-sensitivity displacement transducers and compared to the relative micromotion without axial load. Results: It was found that a larger torsional moment was associated with a larger relative micromotion in both bone defects studied. However, the influence became significant (P < 0.014) in bone models with predominantly larger defect.Furthermore, no significant influence of muscle traction on relative micromotion could be detected for the larger bone models at any of the measurement levels (P = 1.000). In contrast, smaller bones showed no significant differences in muscle traction until a torsional moment of 6 Nm (P < 0.028). Conclusion: In conclusion, a larger torsional moment is associated with a higher relative micromotion and muscle traction, conclusively, has no effect on the primary stability of the reverse prosthesis for a 200 mm bone in vitro.
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Aseptic loosening is a frequent cause for revision of endoprosthesis. X-ray examinations like Radio-Stereometry-Analysis (RSA) are among the most widely used in vivo methods for its detection. Nevertheless, this method is not used routinely because of bone marker and related radiation exposure. This work aims at creating a new in vivo concept to detect implant stability measuring micromotions without x-ray and to develop a corresponding algorithm. Based on the assumption of contactless measurement, the input parameters for the algorithm are the distances of each ultrasound sensor to the object (prosthesis and bone) and its position. First, the number of parameters necessary for a precise reconstruction and measurement of micromotions between objects had to be defined. Therefore, the algorithm has been tested with simulations of these parameters. Two experimental measurements, either using contact sensors or ultrasound, were used to prove the accuracy of the algorithm. Simulations indicate a high accuracy with three distances as initial parameters for each object. Contact measurements show precise representation of micromotion, and the contactless measurements show the possibility of detecting various materials with a high resolution. This work lays the foundations for non-invasive detection of micromotions between the implant-bone interface.
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Prótesis de Cadera , Diseño de Prótesis , HuesosRESUMEN
BACKROUND: Surgical treatment of proximal humeral fractures poses a major challenge, especially in osteoporotic bone. At present, there appears to exist neither a suitable model for research to optimize the osteosynthesis processes nor are the structural data available which are required for developing such a model. Therefore, the aim of this study is to determine the microscopic morphology and Young's modulus of cancellous bone from human humeral heads considering osteoporotic changes. METHODS: Cylindrical samples were taken from ten fresh-frozen human humeral heads and structural analysis was done with µCT. Ten rod-like trabeculae were prepared from five of the humeral heads each which were measured and tested mechanically. For this purpose, the trabeculae were fixed on a slide and rotated axially under a stereo microscope. The sample cross-section and the depending moment of inertia were extracted from the image data. The samples were then loaded in a 2-point bending test and Young's moduli of the samples were determined. RESULTS: It could be shown that with increasing age of the donor, ossified portion of the cancellous bone decreased (p < 0.05). The average degree of mineralization of the bone was 1.24 (±0.06) g/mm3, which decreased with increasing age (p < 0.05). The determined Young's modulus averaged 1.33 (±1.76) GPa. INTERPRETATION: The verified structural parameter showed osteoporotic changes in the examined bone. This study for the first time determined Young's modulus of single trabeculae of cancellous bone of osteoporotically altered human humeral heads. Implementing the non-destructive sample measurement before exposure resulted in a methodical improvement.
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Densidad Ósea , Hueso Esponjoso , Humanos , Módulo de Elasticidad , Fenómenos Biomecánicos , HuesosRESUMEN
Background: Evaluation of the mechanical behavior of the microstructure of cancellous bone seems important for the understanding of the mechanical behavior of bone. Prevention and treatment of fragility fractures due to osteoporosis is a major challenge according to ageing population. A bone model might help to assess fracture risk. Measurement of single trabeculae of bone should give further information compared with bone densitometry alone. This study measures the mechanical properties of single cancellous trabeculae derived from human proximal humerus. Methods: 34 single trabeculae dissected from human humeral heads were measured and evaluated mechanically. Trabeculae were fixed on microscope slides and geometrical data were reported during axial rotation of the specimens to measure the transverse section using computer aided design (CAD). The samples were subjected to a two-point bending test and were loaded with a measure-stamp at a defined distance. Force and deflection were measured by high-resolution sensors. The E-modulus was then calculated in combination with finite elements method simulation (FEM), using the previously obtained CAD-Data. Results: The average E-modulus from 34 valid measurements of human humeral trabeculae was 1678 MPa with a range from 829 to 3396 MPa, which is consistent with existing literature. The planned additional validation of the measurement method using manufactured three-dimensional synthetic trabeculae with known mechanical properties showed an average elastic modulus of single trabeculae of 51.5 MPa, being two dimensions lower than the value reported in the datasheet of the plastic. Conclusion: This newly developed, time and cost-efficient procedure allows the measurement of E-modulus in single trabeculae. Measurement of mechanic parameters of single trabeculae might give insights on mechanic behavior of bone and be relevant for the research of systemic bone diseases, complementing the existing data on bone-mineral-density. Further examination of single trabeculae of human cancellous bone should give an insight on the mechanical behavior of bone also considering systemic bone diseases.
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Rheumatoid arthritis (RA) is associated with systemic osteoporosis, which leads to severe disability and low quality of life. Current therapies target osteoclasts to reduce bone degradation, but more treatment options would be required to promote bone protection by acting directly on osteoblasts (OB). Recently, the local production of dopamine in inflamed joints of RA has been observed. Thus, in this project, we aimed to determine the implication of the neurotransmitter dopamine in the bone formation process in RA. Dopamine receptors (DR) in the human bone tissue of RA or osteoarthritis (OA) patients were examined by immunohistochemistry. DR in isolated human osteoblasts (OB) was analyzed by flow cytometry, and dopamine content was evaluated by ELISA. Osteoclasts (OC) were differentiated from the PBMCs of healthy controls (HC) and RA patients. Isolated cells were treated with specific dopamine agonists. The effect of dopamine on mineralization was evaluated by Alizarin red staining. Cytokine release in supernatants was measured by ELISA. Osteoclastogenesis was evaluated with TRAP staining. OC markers were analyzed via real-time PCR and bone resorption via staining of resorption pits with toluidine blue. All DR were observed in bone tissue, especially in the bone remodeling area. Isolated OB maintained DR expression, which allowed their study in vitro. Isolated OB expressed tyrosine hydroxylase, the rate-limiting enzyme for dopamine production, and contained dopamine. The activation of D2-like DR significantly increased bone mineralization in RA osteoblasts and increased osteoclastogenesis but did not alter the expression of OC markers nor bone resorption. DR were found in the bone remodeling area of human bone tissue and dopamine can be produced by osteoblasts themselves, thus suggesting a local autocrine/paracrine pathway of dopamine in the bone. D2-like DRs are responsible for bone mineralization in osteoblasts from RA patients without an increase in bone resorption, thus suggesting the D2-like DR pathway as a possible future therapeutic target to counteract bone resorption in arthritis.
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Artritis Reumatoide , Resorción Ósea , Artritis Reumatoide/tratamiento farmacológico , Artritis Reumatoide/metabolismo , Dopamina , Humanos , Osteoblastos/metabolismo , Osteogénesis , Calidad de Vida , Receptores DopaminérgicosRESUMEN
(1) Background: Synovial fluid (SF) from knee joints with osteoarthritis (OA) has increased levels of phospholipids (PL). We have reported earlier that TGF-ß and IGF-1 stimulate fibroblast-like synoviocytes (FLS) to synthesize increased amounts of PLs. The current study examined whether IL-1ß induces the release of PLs in FLS and the underlying mechanism. (2) Methods: Cultured human OA FLS were treated with IL-1ß alone and with pathway inhibitors or with synthetic liver X receptor (LXR) agonists. Cholesterol hydroxylases, ABC transporters, apolipoproteins (APO), LXR, sterol regulatory binding proteins (SREBPs), and 3-hydroxy-3-methylglutaryl-coenzyme A reductase (HMGCR) were analyzed by RT-PCR, Western blot, and ELISA. The release of radiolabeled PLs from FLS was determined, and statistical analysis was performed using R (N = 5-9). (3) Results: Like synthetic LXR agonists, IL-1ß induced a 1.4-fold greater release of PLs from FLS. Simultaneously, IL-1ß upregulated the level of the PL transporter ABCA1 and of cholesterol hydroxylases CH25H and CYP7B1. IL-1ß and T0901317 stimulated the expression of SREBP1c, whereas only T0901317 enhanced SREBP2, HMGCR, APOE, LXRα, and ABCG1 additionally. (4) Conclusions: IL-1ß partially controls PL levels in OA-SF by affecting the release of PLs from FLS. Our data show that IL-1ß upregulates cholesterol hydroxylases and thus the formation of oxysterols, which, as natural agonists of LXR, increase the level of active ABCA1, in turn enhancing the release of PLs.
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Benzoatos/farmacología , Bencilaminas/farmacología , Interleucina-1beta/farmacología , Osteoartritis/metabolismo , Fosfolípidos/metabolismo , Sinoviocitos/citología , Transportador 1 de Casete de Unión a ATP/genética , Células Cultivadas , Familia 7 del Citocromo P450/genética , Regulación de la Expresión Génica/efectos de los fármacos , Humanos , Receptores X del Hígado/genética , Osteoartritis/genética , Esteroide Hidroxilasas/genética , Líquido Sinovial/citología , Líquido Sinovial/efectos de los fármacos , Líquido Sinovial/metabolismo , Sinoviocitos/efectos de los fármacos , Sinoviocitos/metabolismoRESUMEN
BACKGROUND: Revision reverse shoulder arthroplasty (RSA) poses considerable surgical challenges. We hypothesized that a newly developed press-fit stem, which is modeled on the medullary canal of the supracondylar region of the distal humerus by a slight distal bend, achieve both correct fit and sufficient primary stability and that additional distal fixation by interlocking screws is favorable in case of advanced humeral bone loss. METHODS: A modular tapered press-fit stem was implanted in 16 Sawbone humeri in three consecutively created defect situations (200 mm (experimental group type 3°), 160 mm (type 4°) and 120 mm (type 5°) bone length above the epicondylar line. In experimental groups type 4° and 5°, additional distal interlocking screw fixation with one to three screws was tested. Primary stability was investigated by measuring micromotions with a high-precision rotational setup. FINDINGS: Highest relative micromotions were noted at the proximal end in experimental groups type 3° and type 4°, whereas in type 5° highest micromotions could be seen at the distal end. Overall micromotions were significantly lower in type 3° and increased with extended defect size. In experimental group type 5°, micromotions increased with reduced additional distal screw fixation. INTERPRETATION: The examined press-fit stem did not provide sufficient primary rotational stability in all constructs without additional support. Advanced distal humeral bone loss had a strong impact on primary fixation. In experimental group type 5° with 120 mm bone remaining, it might be beneficial to use three distal interlocking screws in the supracondylar region in order to neutralize torque and to avoid early loosening.
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Artroplastía de Reemplazo de Hombro , Resorción Ósea/cirugía , Húmero/cirugía , Artroplastía de Reemplazo de Hombro/instrumentación , Tornillos Óseos , Femenino , Humanos , Húmero/patología , Masculino , Diseño de Prótesis , ReoperaciónRESUMEN
The continuous improvement of minimally invasive hip endoprostheses surgery comes with a change in geometries of surgery instruments like the broach handles. Consequently, depending on the handles' curvature this results in a deviation between handle and femoral axis. Therefore, this study aimed to prove the influence of different handles' curvatures on the preparation of implant site and acting forces and moments in this process. Five femoral models attached to different handles (double-curved, single-curved, straight) were locked in a drop-weight device with standardize implantation forces and moments and five strokes were measured for each possible combination. Distribution of force and moment components was dependent on the handle's curvature, where the lowest variation from the standard force values was by the straight one (av:15.2% ± 0.5%) and the strongest discrepancies were exhibit by the double-curved one (av:54.3% ± 0.1%.). Moment values have also shown this trend with the lowest variation (12.4%-23.3%) by the straight one and the highest discrepancies (56,6%-90.9%) by the double-curved one. Results show that unguided axial impact introduces unwanted transverse forces and moments into the femur. Therefore, broach handles should be modified accordingly so that minimally invasive surgery remains feasible but unwanted forces or moments can still be compensated.
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Fémur , Fenómenos Mecánicos , Fémur/cirugía , Humanos , Procedimientos Quirúrgicos Mínimamente InvasivosRESUMEN
BACKGROUND: The purpose of the present study was to assess the impact of the coronavirus disease 2019 (COVID-19) pandemic on orthopaedic and trauma surgery departments in university hospitals in Germany in order to clarify current challenges. METHODS: In this cross-sectional study, an online-based anonymous survey was conducted within the Convention of University Professors of Orthopaedic and Trauma Surgery in Germany from April 3 to April 11, 2020. A bipolar 5-point Likert scale (with possible responses of "totally disagree," "rather disagree," "neutral," "rather agree," and "totally agree") was applied. Fifty-two (69.3%) of 75 clinic directors participated. RESULTS: Communication and cooperation with the government, hospital administration, and other departments during the COVID-19 pandemic were mainly perceived as appropriate. However, only 7 respondents (13.7%) totally agreed or rather agreed with the statement that the authorities are supporters of orthopaedic and trauma surgery departments. Substantial financial and personnel changes in orthopaedic and trauma surgery departments of university hospitals were reported, resulting in an average reduction of 49.4% in operating room capacity and an expected 29.3% loss of revenue. In addition, 14.7% of physicians were reallocated from orthopaedic and trauma surgery to other care-delivery environments. CONCLUSIONS: Our study demonstrated that the COVID-19 pandemic has had a substantial impact on orthopaedic and trauma surgery departments in German university hospitals. Distinct structural and financial effects were noted. Nevertheless, the present study demonstrates the commitment of our specialty to overcome the pandemic by providing competent personnel as well as close cooperation with the hospital administration and other departments. CLINICAL RELEVANCE: To our knowledge, this is the first Germany-wide survey among the heads of orthopaedic and trauma surgery departments in university hospitals on the impact of the COVID-19 pandemic. The survey results may help to inform system-wide decision-making in Germany, in Europe, and beyond.
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Infecciones por Coronavirus/epidemiología , Hospitales Universitarios/organización & administración , Ortopedia/organización & administración , Neumonía Viral/epidemiología , Centros Traumatológicos/organización & administración , Betacoronavirus , COVID-19 , Estudios Transversales , Atención a la Salud/estadística & datos numéricos , Alemania/epidemiología , Encuestas de Atención de la Salud , Humanos , Procedimientos Ortopédicos , Cirujanos Ortopédicos , Pandemias , SARS-CoV-2RESUMEN
Cementless straight stems show very good survival rates. However, the more distal force application of straight stems may lead to release-related proximal stress-shielding. Nevertheless, this technical brief had the objective of conducting a biomechanical in vitro analysis comparing short stems with established straight stems with respect to their primary torsional stability. Two cementless short hip stems and three cementless straight hip stems were implanted in n = 5 synthetic femora each. Torsional torques were applied into the hip stems at a continuous interval of ±7 Nm. Micromotions were measured by six inductive extensometers on four different measurement levels. At the proximal measuring point, significantly smaller relative micromotions of the CLS® prosthesis could be detected compared to all other stem models (p < 0.05). In all stem models, smallest relative micromotions were found at the metaphyseal/diaphyseal measuring point. Only at the measuring point of the distal tips of the straight stems, statistically significantly lower relative micromotion of the CLS® stem compared to the Trendhip® stem could be found (p < 0.01). All the investigated stems generally display a rather comparable anchoring pattern and an almost physiological force application. Since the comparatively long straight stems present an anchoring pattern nearly identical to that of the examined short stems, a shortening of the established straight stems could be taken into consideration. This would offer the advantage of minimally invasive surgery and bone-saving resection as well as preservation of cancellous bone in case a revision would become necessary.
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Prótesis de Cadera , Artroplastia de Reemplazo de Cadera , Fenómenos Biomecánicos , Fémur , Diseño de Prótesis , Estrés MecánicoRESUMEN
INTRODUCTION: Good osteointegration of implants requires sufficient primary stability. Aim of this study was to examine the influence of screw fixation on the primary stability of press-fit cups. METHODS: Two press-fit acetabular cups were tested with regard to the influence and number of screws and their primary stability. RESULTS: For the relatively thin-walled Allofit®-S cup, an influence of the number of screws on the different forms of movement could be demonstrated. CONCLUSIONS: We see a clear influence of the cup wall thickness on the elastic deformability and accordingly on the primary stability of the examined cups.
RESUMEN
Allogeneic bone derived from living donors being necessary to match demand for bone transplantation and thermodisinfection of femoral heads is an established sterilization method. During the thermodisinfection the peripheral bone is exposed to maximum 86 °C for 94 min providing 82.5 °C within the center of the femoral head for at least 15 min. This study examined the compression force of the central and representative peripheral regions of native and thermodisinfected human femoral heads to observe wether different duration and intensity of heat exposure might alter mechanic behaviour. Slices from the equatorial region of human femoral heads were taken from each 14 native and thermodisinfected human femoral heads. The central area revealed a significantly higher compression force for native (p ≤ 0.001) and for thermodisinfected bone (p = 0.002 and p = 0.005) compared with peripheral regions since no relevant differences were found between the peripheral and intermediate areas themselves. A small reduction of compression force for thermodisinfected bone was shown since this did not appear significant due to the small number of specimens. The heat exposure did not alter the pre-existing anatomical changes of the microarchitecture of the native femoral heads from the center towards the peripheral regions. The heterogeneity of microstructure of the femoral head might be of interest concerning clinical applications of bone grafts since the difference between native and thermodisinfected bone appears moderate as shown previously. The different quantity of heat exposure did not reveal any significant influence on compression force which might enable thermodisinfection of preformed bone pieces for surgical indications.