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INTRODUCTION: Aim of this study was to biomechanically compare two different acetabular cup fixation constructs in terms of fracture fixation for displaced acetabular fractures involving the anterior column with hemitransverse fracture under partial and full weight-bearing conditions. METHODS: Two different reinforcement rings designed as cages for primary THA were biomechanically tested in terms of managing a complex acetabular fracture. Single-leg stance cyclic loading was performed to assess fracture gap movement and fragment rotation. Twelve hemi pelvis Sawbones were divided into two groups: primary THA with acetabulum roof reinforcement plate (ARRP) (n = 6) and primary THA with Burch-Schneider reinforcement cage (BSRC) (n = 6). RESULTS: During loading under partial weight-bearing (250 N) fracture gap movement tended to be larger in the BSRC group as compared to the ARRP group. Under full weight-bearing conditions, the ARRP showed 60% significantly less motion (p = 0.035) of the os ilium to os ischii gap compared to BSRC. Fracture gap movements between the os ilium and spina iliaca fragments were significantly reduced by 76% (p = 0.048) for ARRP in contrast to BSRC. The ARRP group also demonstrated significantly less movement in the fracture gaps os ischii to quadrilateral plate (62% reduction, p = 0.009) and quadrilateral plate to spina iliaca (87% reduction, p < 0.001). Significantly less rotational movement of the quadrilateral plate to the os ilium was exhibited by the ARRP group (p = 0.015). CONCLUSIONS: The presented acetabulum roof-reinforcement plate (ARRP) provides stable conditions at the acetabular component with adequate stabilization of a displaced acetabular fracture.
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Acetábulo , Artroplastia de Quadril/instrumentação , Fenômenos Biomecânicos/fisiologia , Placas Ósseas/normas , Fraturas Ósseas/cirurgia , Fixadores Internos/normas , Teste de Materiais/métodos , Suporte de Carga/fisiologia , Acetábulo/lesões , Acetábulo/cirurgia , Idoso , Artroplastia de Quadril/métodos , Pesquisa Comparativa da Efetividade , Fratura-Luxação/cirurgia , Humanos , Resultado do TratamentoRESUMO
BACKGROUND: The aim of the study was to analyze the effect of local infiltration analgesia (LIA), peripheral nerve blocks, general and spinal anesthesia on early functional recovery and pain control in primary unicompartmental knee arthroplasty (UKA). METHODS: Between January 2016 until August 2016, 134 patients underwent primary UKA and were subdivided into four groups according to their concomitant pain and anesthetic procedure with catheter-based techniques of femoral and sciatic nerve block (group GA&FNB, n = 38) or epidural catheter (group SP&EPI, n = 20) in combination with general anesthesia or spinal anesthesia, respectively, and LIA combined with general anesthesia (group GA&LIA, n = 46) or spinal anesthesia (group SP&LIA, n = 30). Outcome parameters focused on the evaluation of pain (NRS scores), mobilization, muscle strength and range of motion up to 7 days postoperatively. The cumulative consumption of (rescue) pain medication was analyzed. RESULTS: The LIA groups revealed significantly lower (about 50%) mean NRS scores (at rest) compared to the catheter-based groups at the day of surgery. In the early postoperative period, the dose of hydromorphone as rescue pain medication was significantly lower (up to 68%) in patients with SP&EPI compared to all other groups. No significant differences could be detected with regard to grade of mobilization, muscle strength and range of motion. However, there seemed to be a trend towards improved mobilization and muscle strength with general anesthesia and LIA, whereof general anesthesia generally tended to ameliorate mobilization. CONCLUSIONS: Except for a significant lower NRS score at rest in the LIA groups at day of surgery, pain relief was comparable in all groups without clinically relevant differences, while the use of opioids was significantly lower in patients with SP&EPI. A clear clinically relevant benefit for LIA in UKA cannot be stated. However, LIA offers a safe and effective treatment option comparable to the well-established conventional procedures.
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Anestesia Geral/tendências , Anestesia Local/tendências , Raquianestesia/tendências , Artroplastia do Joelho/tendências , Bloqueio Nervoso Autônomo/tendências , Recuperação de Função Fisiológica/fisiologia , Idoso , Idoso de 80 Anos ou mais , Anestesia Geral/métodos , Anestesia Local/métodos , Raquianestesia/métodos , Anestésicos Locais/administração & dosagem , Artroplastia do Joelho/efeitos adversos , Artroplastia do Joelho/métodos , Bloqueio Nervoso Autônomo/métodos , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Osteoartrite do Joelho/diagnóstico , Osteoartrite do Joelho/cirurgia , Manejo da Dor/métodos , Manejo da Dor/tendências , Dor Pós-Operatória/etiologia , Dor Pós-Operatória/prevenção & controle , Recuperação de Função Fisiológica/efeitos dos fármacos , Estudos Retrospectivos , Resultado do TratamentoRESUMO
BACKGROUND: Postoperative pain control and enhanced mobilization, muscle strength and range of motion following total knee arthroplasty (TKA) are pivotal requisites to optimize rehabilitation and early recovery. The aim of the study was to analyze the effect of local infiltration analgesia (LIA), peripheral nerve blocks, general and spinal anesthesia on early functional recovery and pain control in primary total knee arthroplasty. METHODS: Between January 2016 until August 2016, 280 patients underwent primary TKA and were subdivided into four groups according to their concomitant pain and anesthetic procedure with catheter-based techniques of femoral and sciatic nerve block (group GA&FNB, n = 81) or epidural catheter (group SP&EPI, n = 51) in combination with general anesthesia or spinal anesthesia, respectively, and LIA combined with general anesthesia (group GA&LIA, n = 86) or spinal anesthesia (group SP&LIA, n = 61). Outcome parameters focused on the evaluation of pain (NRS scores), mobilization, muscle strength and range of motion up to 7 days postoperatively. The cumulative consumption of (rescue) pain medication was analyzed. RESULTS: Pain relief was similar in all groups, while the use of opioid medication was significantly lower (up to 58%) in combination with spinal anesthesia, especially in SP&EPI. The LIA groups, in contrast, revealed significant higher mobilization (up to 26%) and muscle strength (up to 20%) in the early postoperative period. No analgesic technique-related or surgery-related complications occurred within the first 7 days. Due to insufficient pain relief, 8.4% of the patients in the catheter-based groups and 12.2% in the LIA groups resulted in a change of the anesthetics pain management. CONCLUSIONS: The LIA technique offers a safe and effective treatment option concerning early functional recovery and pain control in TKA. Significant advantages were shown for mobilization and muscle strength in the early postoperative period while pain relief was comparable within the groups.
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Anestesia Geral/tendências , Anestesia Local/tendências , Raquianestesia/tendências , Artroplastia do Joelho/tendências , Bloqueio Nervoso Autônomo/tendências , Manejo da Dor/tendências , Idoso , Idoso de 80 Anos ou mais , Anestesia Geral/métodos , Anestesia Local/métodos , Raquianestesia/métodos , Artroplastia do Joelho/métodos , Bloqueio Nervoso Autônomo/métodos , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Manejo da Dor/métodos , Dor Pós-Operatória/diagnóstico por imagem , Dor Pós-Operatória/prevenção & controle , Amplitude de Movimento Articular/efeitos dos fármacos , Amplitude de Movimento Articular/fisiologia , Recuperação de Função Fisiológica/efeitos dos fármacos , Recuperação de Função Fisiológica/fisiologia , Estudos Retrospectivos , Resultado do TratamentoRESUMO
Key factors for successful osteosynthetic fracture stabilization are anatomical fracture reduction, restoration of axis and torsion alignment as well as tissue-preserving operative techniques. In long bone fractures, the use of intramedullary long bridging nailing offers ideal conditions for bone healing, as axial and rotational stability is provided by canal-filling nails and locking screws. In addition, the tissue in the fracture region is protected as the intramedullary nail insertion is distant from the fracture. The indication spectrum for modern intramedullary locked nailing includes diaphyseal fractures of long bones, metaphyseal fractures and reconstructions, as well as treatment of nonunion, osteotomy and arthrodesis of the lower extremities. Continuous improvements in nail design and instrumentation as well as the introduction of anatomical reconstruction nails will optimize the spectrum and effectiveness of intramedullary osteosynthesis even further.
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Fixação Intramedular de Fraturas/métodos , Fixação Intramedular de Fraturas/normas , Fraturas Ósseas/cirurgia , Consolidação da Fratura , Fraturas Ósseas/complicações , HumanosRESUMO
BACKGROUND: Osteosynthesis of distal tibia fractures relies on stable fixation of the distal fragment. Modern intramedullary implants provide various fixation options for locking screws. These implants expand the indications for intramedullary nailing of tibia fractures towards more distally located fractures. MATERIAL AND METHODS: The most essential options which improve the fixation of the distal fragment include an increase in number, in size and in spacing of the distal locking screws. Further options for nailing of distal tibia fractures include interfragmentary compression and angular stability. Interfragmentary compression considerably increases mechanical stability in axially stable fracture situations. Angular stable fixation of the locking screws has recently become a popular feature in intramedullary nailing; however, the effect of angular stability on the mechanical properties of distal tibia osteosynthesis has been found to be limited. CONCLUSION: The initial stability to provide sufficient load bearing capacity appears to be provided by the available locking options. With at least two screws, preferably in crossed configuration and spaced over the largest available distance of the distal fragment, secure and stable fixation can be achieved. Insertion of the locking screws in a free hand technique typically results in jamming of the locking screw with the nail and with cortical bone, providing inherent angular stability of the construct. Angular stable locking features of the nail itself do not appear to improve mechanical stability or to affect healing of distal tibia fractures.
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Fraturas do Tornozelo/cirurgia , Pinos Ortopédicos , Placas Ósseas , Parafusos Ósseos , Fixação Intramedular de Fraturas/instrumentação , Fraturas da Tíbia/cirurgia , Fraturas do Tornozelo/diagnóstico , Humanos , Desenho de Prótese , Fraturas da Tíbia/diagnóstico , Resultado do TratamentoRESUMO
The success of surgical treatment for fractures hinges on various factors, notably accurate surgical indication. The process of developing and certifying a new osteosynthesis device is a lengthy and costly process that requires multiple cycles of review and validation. Current methods, however, often rely on predecessor standards rather than physiological loads in specific anatomical locations. This study aimed to determine actual loads experienced by an osteosynthesis plate, exemplified by a standard locking plate for the femoral shaft, utilizing finite elements analysis (FEA) and to obtain the bending moments for implant development standard tests. A protocol was developed, involving the creation and validation of a fractured femur model fixed with a locking plate, mechanical testing, and FEA. The model's validation demonstrated exceptional accuracy in predicting deformations, and the FEA revealed peak stresses in the fracture bridging zone. Results of a parametric analysis indicate that larger fracture gaps significantly impact implant mechanical behavior, potentially compromising stability. This study underscores the critical need for realistic physiological conditions in implant evaluations, providing an innovative translational approach to identify internal loads and optimize implant designs. In conclusion, this research contributes to enhancing the understanding of implant performance under physiological conditions, promoting improved designs and evaluations in fracture treatments.
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Fraturas do Fêmur , Fêmur , Análise de Elementos Finitos , Estresse Mecânico , Humanos , Fêmur/fisiologia , Fêmur/cirurgia , Fraturas do Fêmur/cirurgia , Fraturas do Fêmur/fisiopatologia , Placas Ósseas , Suporte de Carga/fisiologia , Fixação Interna de Fraturas/métodos , Fixação Interna de Fraturas/instrumentação , Modelos Biológicos , Fenômenos BiomecânicosRESUMO
BACKGROUND: Fractures of the distal radius represent the most common fractures in adults. Volar locked plating has become a popular method for treating these fractures, but has been subject to several shortcomings in osteoporotic bone, such as loss of reduction and screw purchase. In order to overcome these shortcomings, cement augmentation has been proposed. METHODS: AO-type 23-A3.3 fractures were made in 8 pairs of fresh frozen osteoporotic cadaveric radial bones. All specimens were treated with volar plating, and divided into cement augmentation or non-augmentation groups (n = 8/group). Constructs were tested dynamically and load to failure, construct-stiffness, fracture gap movement and screw cutting distance were measured. RESULTS: Cement augmentation resulted in a significant increase in cycles and load to failure, as well as construct stiffness at loads higher than 325 N. When compared to the non-augmented group, fracture gap movement decreased significantly at this load and higher, as did screw cutting distance at the holes of the ulnar column. The cycles to failure depend on the BMD in the distal region of the radius. CONCLUSION: Cement augmentation improves biomechanical properties in volar plating of the distal radius.
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Fixação Interna de Fraturas/métodos , Osteoporose/cirurgia , Fraturas do Rádio/cirurgia , Idoso , Fenômenos Biomecânicos , Cimentos Ósseos , Placas Ósseas , Transplante Ósseo , Cadáver , Feminino , Humanos , Masculino , Osteoporose/fisiopatologia , Fraturas do Rádio/fisiopatologiaRESUMO
BACKGROUND: Distal radius fractures continue to show significant complication rates after operative treatment with locked plating. Failure occurs by screw loosening or screw penetration in the distal fragment. Placement of additional screws may enhance the stiffness of fracture fixation. The aim of this study was to determine the fatigue properties of different screw configurations in distal radius plate osteosynthesis with biomechanical tests and finite element analysis (FEA). MATERIAL AND METHODS: Unstable distal radius fractures were created in 12 human cadaveric bone specimens and were fixed with volar locking plates. Group 4SC was fixed with four screws in the distal row and group 6SC with two additional screws the row below. Dynamic loading was applied physiologically. The radial shortening, the angulation of the distal fragment and the failure mechanism were determined by experimental tests and were further elucidated by FEA. RESULTS: Group 6SC showed a significantly lower radial shortening and inclination. Breakage of the screws within the plate was noted in group 4SC, while moderate screw penetration was observed in group 6SC. FEA confirmed the biomechanical tests. In group 4SC elevated von Mises strain in the locking mechanism explained the inclination of the screws and the distal fragment. The elastic strain in group 6SC was increased at the screw-bone interface which explained the resulting screw penetration. CONCLUSION: The failure mechanism in volar plating of distal radius fractures depended on the number of screws and their configuration. Using two more screws increases construct stiffness and angular stability under dynamic loading. However, increased stiffness also promoted screw penetration mainly in osteoporotic bone. Compared to screw penetration, loss of reposition and inclination of the distal fragment observed in the 4SC configuration is more likely to result in clinical complications.
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Placas Ósseas/efeitos adversos , Parafusos Ósseos/efeitos adversos , Instabilidade Articular/etiologia , Fraturas por Osteoporose/cirurgia , Fraturas do Rádio/cirurgia , Idoso , Idoso de 80 Anos ou mais , Cadáver , Módulo de Elasticidade , Análise de Falha de Equipamento , Feminino , Fixação Interna de Fraturas/efeitos adversos , Fixação Interna de Fraturas/instrumentação , Fricção , Mãos/cirurgia , Humanos , Instabilidade Articular/fisiopatologia , Masculino , Fraturas por Osteoporose/fisiopatologia , Desenho de Prótese , Falha de Prótese , Fraturas do Rádio/fisiopatologia , Resistência à Tração , Resultado do Tratamento , Traumatismos do Punho/fisiopatologia , Traumatismos do Punho/cirurgiaRESUMO
Diabetes mellitus is a risk factor for various types of tendon disorders. The mechanisms underlying diabetes associated tendinopathies remain unclear, but typically, systemic factors related to high blood glucose levels are thought to be causally involved. We hypothesize that tendon immanent cells might be directly involved in diabetic tendinopathy. We therefore analyzed human and rat tendons by immunohistochemistry, laser capture microdissection, and single cell PCR for pancreatic ß-cell associated markers. Moreover, we examined the short term effects of a single injection of streptozotocin, a toxin for GLUT2 expressing cells, in rats on insulin expression of tendon cells, and on the biomechanical properties of Achilles tendons. Tendon cells, both in the perivascular area and in the dense collagenous tissue express insulin and Glut2 on both protein and mRNA levels. In addition, glucagon and PDX-1 are present in tendon cells. Intraperitoneal injection of streptozotocin caused a loss of insulin and insulin mRNA in rat Achilles tendons after only 5 days, accompanied by a 40% reduction of mechanical strength. In summary, a so far unrecognized, extrapancreatic, insulin-producing cell type, possibly playing a major role in the pathophysiology of diabetic tendinopathy is described. In view of these data, novel strategies in tendon repair may be considered. The potential of the described cells as a tool for treating diabetes needs to be addressed by further studies.
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Células Secretoras de Insulina/metabolismo , Células Secretoras de Insulina/patologia , Insulina/biossíntese , Tendões/patologia , Tendão do Calcâneo/metabolismo , Tendão do Calcâneo/patologia , Adulto , Idoso , Animais , Western Blotting , Diabetes Mellitus/patologia , Feminino , Glucose/farmacologia , Humanos , Imuno-Histoquímica , Insulina/metabolismo , Secreção de Insulina , Células Secretoras de Insulina/efeitos dos fármacos , Masculino , Pessoa de Meia-Idade , Ratos , Adulto JovemRESUMO
BACKGROUND: Optimizing the needle position using ultrasound (US) instead of electrical nerve stimulation (NSt) is increasingly common for perivascular brachial plexus block. These two methods were compared in a prospective, randomized, single-blinded controlled trial regarding effectiveness and time of onset of peripheral nerve blockade. METHODS: After puncture (penetration of neurovascular sheath and complete insertion of needle) 56 patients were randomly assigned to either the US group (finding the needle tip in transpectoral section, short axis, correction of needle position if local anesthetic spread was insufficient) or the NSt group (target impulse reaction in median, ulnar or radial nerve of 0.3 mA/0.1 ms, if necessary correction of position before injection of local anesthetic) to verify the needle position. All patients received 500 mg 1% mepivacaine. Sensory and motor blocks were tested by single nerve measurements (SNM) 5, 10 and 20 min after finishing the injection, where 0 represents minimal and 2 maximal success of the block. RESULTS: Single nerve measurements were analyzed using repeated measures ANOVA. The mean results of cumulative SNMs were significantly higher in the US group at all measurement times. Sensitivity US/NSt: 5 min: 3.36±2.32/2.63±1.87; 10 min: 5.45±2.41/4.21±2.45; 20 min: 7.30±2.02/6.43±2.43, p=0.015, motor function US/NSt: 5 min: 3.91±1.81/3.02±1.67; 10 min: 5.27±1.66/4.05±1.70; 20 min: 6.64±1.37/5.50±1.90, p<0.001. At the beginning of surgery complete nerve blockade was achieved in 89% in the US group and 68% in the NSt group (p=0.006), 3 (US) versus 7 (NSt) patients needed supplementation and 3 (US) versus 11 (NSt) patients needed general anesthesia (p=0.022). To achieve the nerve block took approximately 1 min more in the US group (p=0.003). CONCLUSION: The use of ultrasound in perivascular brachial plexus blocks leads to significantly higher success rates and shorter times of onset.
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Plexo Braquial/diagnóstico por imagem , Bloqueio Nervoso/métodos , Adulto , Idoso , Anestésicos Locais/administração & dosagem , Método Duplo-Cego , Estimulação Elétrica , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Agulhas , Medição da Dor , Estudos Prospectivos , Resultado do Tratamento , UltrassonografiaRESUMO
Two cases of increased bone density after callus distraction are described following percutaneous administration of 3.5 mg recombinant bone morphogenetic protein-7 (rhBMP-7). Both patients underwent segmental resection and segmental transport for osteomyelitis of the long bones (femur and tibia) but no callus maturation occurred. After percutaneous administration of rhBMP-7 the callus density increased in both cases.
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Proteína Morfogenética Óssea 7/administração & dosagem , Calo Ósseo/efeitos dos fármacos , Consolidação da Fratura/efeitos dos fármacos , Osteíte/tratamento farmacológico , Osteíte/cirurgia , Osteogênese por Distração , Administração Tópica , Adulto , Humanos , Peptídeos e Proteínas de Sinalização Intercelular/administração & dosagem , Masculino , Osteíte/complicações , Resultado do Tratamento , Adulto JovemRESUMO
The amount of interfragmentary movement has been identified as a crucial factor for successful fracture healing. The aim of our study was to combine finite element analysis with a rigid body assumption to efficiently predict interfragmentary movement in fixed tibial fractures. The interfragmentary movement in a transverse tibial shaft fracture (AO/OTA type 42-A3) fixed with a locked plating construct was simulated using finite element analysis. In order to assess the contribution of the components on the resulting interfragmentary movement, the tibia, screws and embedding was either simulated deformable or as rigid body. The rigid and the deformable model accurately predicted the interfragmentary movement (R2 = 0.99). The axial movement ranged between 0.1 mm and 1.3 mm and shear movements were between 0.2 mm and 0.5 mm. Differences between the two models were smaller than 73 µm (axial) and 46 µm (shear). The rigid body assumption reduced computation time and memory usage by up to 61% and 97%, respectively.
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Placas Ósseas , Fraturas da Tíbia , Fenômenos Biomecânicos , Parafusos Ósseos , Análise de Elementos Finitos , Fixação Interna de Fraturas , Humanos , Fraturas da Tíbia/diagnóstico por imagem , Fraturas da Tíbia/cirurgiaRESUMO
The aim of this study was to test the hypothesis that a reinforced gamma nail for the fixation of subtrochanteric fractures would experience less stress during loading compared with a common gamma nail. The issue of whether the use of the stronger implant would result in more stress shielding in the surrounding bone was also addressed. A finite element analysis (FEA) of a synthetic bone was employed to calculate the stress distribution in implant and bone for two fracture types (AO 31-A3.1 and AO 31-A3.3). The FEA was validated by mechanical tests on six synthetic femurs. To test the hypothesis in vitro, mechanical tests on six pairs of fresh-frozen human femurs were conducted. The femurs were supplied with a common or a reinforced gamma nail in a cross-over study design. Strains were measured on the nail shaft to quantify the loading of the nail. The FEA resulted in 3-51 per cent lower stresses for the reinforced gamma nail. No increase in stress shielding could be observed. In the in-vitro tests, the reinforced gamma nail experienced less strain during loading (p < 0.016). The study demonstrated the benefit of a reinforced gamma nail in subtrochanteric fractures. It experienced less stress but did not result in more stress shielding.
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Pinos Ortopédicos , Fêmur/cirurgia , Análise de Elementos Finitos , Idoso , Fenômenos Biomecânicos , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Modelos Biológicos , Reprodutibilidade dos TestesRESUMO
The purpose of this study was to address the question of how the stability of a proximal hip fracture determines the fatigue and failure mechanism of an intramedullary implant. To answer this question, mechanical experiments and finite element simulations with two different loading scenarios were conducted. The two load scenarios differed in the mechanical support of the fracture by an artificial bone sleeve, representing the femoral head and neck. The experiments confirmed that an intramedullary nail fails at a lower load in an unstable fracture situation in the proximal femur than in a stable fracture. The nails with an unstable support failed at a load 28 per cent lower than the nails with a stable support by the femoral neck. Hence, the mechanical support of a fracture is crucial to the fatigue failure of an implant. The simulation showed why the fatigue fracture of the nail starts at the aperture of the lag screw. It is the location of the highest von Mises stress, which is the failure criterion for ductile materials.
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Pinos Ortopédicos , Fixação Intramedular de Fraturas/instrumentação , Fixação Intramedular de Fraturas/métodos , Fraturas do Quadril/fisiopatologia , Fraturas do Quadril/cirurgia , Instabilidade Articular/fisiopatologia , Instabilidade Articular/cirurgia , Cadáver , Simulação por Computador , Análise de Falha de Equipamento , Fraturas do Quadril/complicações , Humanos , Instabilidade Articular/etiologia , Modelos Biológicos , Desenho de Prótese , Falha de Prótese , Estresse MecânicoRESUMO
Osteoporosis is characterized by a reduction of bone mass and changes in bone micro-architecture. The resulting reduction in bone strength leads to the well recognized increase in the risk of fracture, particularly at the radius, hip, and spine. The treatment of osteoporotic fractures is challenged by the reduced mechanical capacity of osteoporotic bone, reflected in reduced holding power and increased fragility. The aim of successful fracture treatment in individuals with osteoporosis is early fixation of the fracture with immediate and almost unrestricted weight-bearing capacity. The key factor for effective fracture treatment is strict adherence to the basic principles of stable fracture fixation: reposition, compression, long, wide supports, as well as additive techniques such as angular stability and bone augmentation. Modern osteosynthesis implants effectively support the application of these principles. Modifications in implant design and techniques enable the surgeon to apply and combine the essential components of the basic principles for the treatment of mechanically impaired bone. The key components employed in modern implants include integrated compression techniques, multidirectional angular stability, expandable support surfaces, as well as multiple augmentation options. However, despite modern implant technology, osteoporotic bone fractures remain a significant challenge for the orthopaedic surgeon and require meticulous planning and implementation of the basic principles.
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Fixação Interna de Fraturas/instrumentação , Fraturas Espontâneas/cirurgia , Osteoporose/cirurgia , Idoso , Fenômenos Biomecânicos , Cimentos Ósseos/uso terapêutico , Densidade Óssea/fisiologia , Pinos Ortopédicos , Placas Ósseas , Parafusos Ósseos , Desenho de Equipamento , Feminino , Fixação Interna de Fraturas/métodos , Fixação Intramedular de Fraturas/instrumentação , Consolidação da Fratura/fisiologia , Fraturas Espontâneas/fisiopatologia , Humanos , Masculino , Pessoa de Meia-Idade , Osteoporose/fisiopatologia , Vertebroplastia/instrumentaçãoRESUMO
Following trauma or surgery on the musculoskeletal system the primary aim is always as complete a restitution of mobility as possible. By mobilization with partial weight-bearing this is possible. The preferred way of teaching partial weight-bearing is the use of conventional bathroom scales. This method proves to be simple as well as time and cost-saving, but the transferability to the patient's daily life is questionable. Training and control of partial weight-bearing under dynamic conditions, such as normal walking, and walking up and down stairs seem to be very important. Different investigations have shown that the minority of subjects recruited could manage to maintain the given load of partial weight-bearing. Furthermore, the actual resulting moments within the joints, caused by muscles, fascia and tendons, are not considered in presets of partial weight-bearing, as only external forces (ground reaction forces) are measured. However, the problems in teaching partial weight-bearing have to be contrasted with the as yet unexplained issue of postoperative partial versus full weight-bearing.
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Biorretroalimentação Psicológica/métodos , Instabilidade Articular/reabilitação , Instabilidade Articular/cirurgia , Modalidades de Fisioterapia , Suporte de Carga , Humanos , Cuidados Pós-Operatórios/métodosRESUMO
AIMS: Evaluate if treating an unstable femoral neck fracture with a locking plate and spring-loaded telescoping screw system would improve construct stability compared to gold standard treatment methods. METHODS: A 31B2 Pauwels' type III osteotomy with additional posterior wedge was cut into 30 fresh-frozen femur cadavers implanted with either: three cannulated screws in an inverted triangle configuration (CS), a sliding hip screw and anti-rotation screw (SHS), or a locking plate system with spring-loaded telescoping screws (LP). Dynamic cyclic compressive testing representative of walking with increasing weight-bearing was applied until failure was observed. Loss of fracture reduction was recorded using a high-resolution optical motion tracking system. RESULTS: LP constructs demonstrated the highest mean values for initial stiffness and failure load. LP and SHS constructs survived on mean over 50% more cycles and to loads 450 N higher than CS. During the early stages of cyclic loading, mean varus collapse of the femoral head was 0.5° (SD 0.8°) for LP, 0.7° (SD 0.7°) for SHS, and 1.9° (SD 2.3°) for CS (p = 0.071). At 30,000 cycles (1,050 N) mean femoral neck shortening was 1.8 mm (SD 1.9) for LP, 2.0 mm (SD 0.9) for SHS, and 3.2 mm (SD 2.5) for CS (p = 0.262). Mean leg shortening at construct failure was 4.9 mm (SD 2.7) for LP, 8.9 mm (SD 3.2) for SHS, and 7.0 mm (SD 4.3) for CS (p = 0.046). CONCLUSION: Use of the LP system provided similar (hip screw) or better (cannulated screws) biomechanical performance as the current gold standard methods suggesting that the LP system could be a promising alternative for the treatment of unstable fractures of the femoral neck.Cite this article: Bone Joint Res 2020;9(6):314-321.
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Bone graft substitutes often exhibit poor bone regeneration in large defects because of inadequate vascularization. Studies have shown that if blood supply is compromised, application of osteogenic factors alone could not induce successful healing. This study was to evaluate the effects of vascular endothelial growth factor, which combined with a coralline scaffold, on vascularization, scaffold resorption and osteogenesis in a rabbit radius critical size defect model. The scaffold was either coated with a control-plasmid DNA (group 1), coated with VEGF-plasmid DNA (group 2), loaded with mesenchymal stem cells (BMSC) transfected with control plasmid (group 3) or with both stem cells and the VEGF plasmid (group 4). X-rays were taken every 4 weeks up to week 16, when animals were euthanized. The volume of new bone was measured by mu-CT scans and blood vessels were counted after anti-CD31 staining of endothelial cells. The results from the solitary VEGF- and VEGF-transfected cells (groups 2 and 4) demonstrated significantly enhanced vascularization, osteogenesis and resorption of the carrier when compared to the control group. The highest degree of osteogenesis was found when the carrier was loaded with BMSC (group 3), whereas VEGF-transfected cells led to the highest vascularization and fastest resorption of the bone substitute. Additionally, VEGF-transfected BMSC led to a more homogenous vascularization of the defect. The results indicate that VEGF can be a helpful factor to improve healing in large bone defects, in which bone substitutes will otherwise not be vascularized and replaced by fresh bone.
Assuntos
Células da Medula Óssea/efeitos dos fármacos , Células da Medula Óssea/metabolismo , Substitutos Ósseos/farmacologia , Células Estromais/efeitos dos fármacos , Células Estromais/metabolismo , Fator A de Crescimento do Endotélio Vascular/biossíntese , Animais , Reabsorção Óssea/tratamento farmacológico , Reabsorção Óssea/genética , Reabsorção Óssea/metabolismo , Reabsorção Óssea/patologia , Substitutos Ósseos/uso terapêutico , Células Cultivadas , Feminino , Fraturas Ósseas/diagnóstico por imagem , Fraturas Ósseas/tratamento farmacológico , Terapia Genética , Humanos , Imageamento Tridimensional , Coelhos , Radiografia , Fatores de Tempo , Tomógrafos Computadorizados , Fator A de Crescimento do Endotélio Vascular/genéticaRESUMO
BACKGROUND: Our objective was to determine the biomechanical primary stability of two different side plate fixation devices in an unstable intertrochanteric cadaver model: the Sliding Hip Screw with an additional derotation screw was compared with the Percutaneous Compression Plate. METHODS: Eight pairs of human cadaver femurs were tested for comparison of the primary stability of the two implants in two modes: (a) cyclic loading up to 200 N, 400 N, 600 N, 800 N, and 1000 N, respectively. In vitro combined axial and bending loads were applied. Angular displacements of the proximal head fragment during loading were recorded in rotational, varus-valgus, and anterior-posterior directions. (b) The load to failure was determined. FINDINGS: Specimens fixed with the Percutaneous Compression Plate showed higher displacements in the varus during loading up to 200 N (P=0.033), and 400 N (P=0.001), compared to the Sliding Hip Screw. A similar tendency was observed for higher loads. The Percutaneous Compression Plate allowed more external rotation of the proximal fragment only at loads up to 800 N (P=0.019). No statistical difference could be found for the slight migrations in the posterior direction. Load to failure also revealed no statistical difference between the two implants. INTERPRETATION: The Percutaneous Compression Plate as a double-axis fixation device with a sliding capability allows higher displacements in the varus direction and also in external rotation at 800 N loading compared to the Sliding Hip Screw as a single-axis fixation device combined with an additional derotation screw. While both implants are successful used in clinical practice, this should be considered in treatment of unstable intertrochanteric fractures with inferior comminution in osteoporotic patients.