RESUMEN
Total hip arthroplasty (THA) is a successful surgery in the treatment of hip pain, but there are potential complications, of which dislocation is one of the most common. Dislocation management is a challenging problem that requires a multimodal approach, and the use of dual mobility implants is an option. We present a patient with a history of femoral neck fracture who underwent THA with a double mobility implant. On the 18 th postoperative day, after a fall to the ground, she developed prosthesis dislocation and had a complication after closed reduction, a subsequent intraprosthetic dislocation. After a radiographic diagnosis, the patient presented mechanical signs of hip flexion caused by a disassociated double mobility implant. The revision surgery was indicated, but the patient chose not to perform the necessary surgical procedure. A careful postoperative study of the radiographs revealed an eccentric femoral head and evidence of disassociated implantation in the surrounding soft tissues. Radiographs after closed reduction of intraprosthetic dislocations should be examined thoroughly.
RESUMEN
Abstract Total hip arthroplasty (THA) is a successful surgery in the treatment of hip pain, but there are potential complications, of which dislocation is one of the most common. Dislocation management is a challenging problem that requires a multimodal approach, and the use of dual mobility implants is an option. We present a patient with a history of femoral neck fracture who underwent THA with a double mobility implant. On the 18th postoperative day, after a fall to the ground, she developed prosthesis dislocation and had a complication after closed reduction, a subsequent intraprosthetic dislocation. After a radiographic diagnosis, the patient presented mechanical signs of hip flexion caused by a disassociated double mobility implant. The revision surgery was indicated, but the patient chose not to perform the necessary surgical procedure. A careful postoperative study of the radiographs revealed an eccentric femoral head and evidence of disassociated implantation in the surrounding soft tissues. Radiographs after closed reduction of intraprosthetic dislocations should be examined thoroughly.
Resumo A artroplastia total do quadril (ATQ) é uma cirurgia bem-sucedida no tratamento da dor no quadril, mas existem complicações potenciais, das quais a luxação é uma das mais comuns. O gerenciamento das luxações é um problema desafiador que requer uma abordagem multimodal, e o uso de implantes de mobilidade dupla é uma opção. Apresentamos uma paciente com história de fratura do colo do fêmur que foi submetida a ATQ com um implante de dupla mobilidade. No 18° dia pós-operatório, após queda ao solo, a paciente evoluiu com luxação da prótese e teve uma complicação após redução fechada, uma luxação intraprotética subsequente. Após um diagnóstico radiográfico, a paciente apresentou sinais mecânicos na flexão do quadril causados por um implante de mobilidade dupla desassociado. A cirurgia de revisão foi indicada, mas a paciente optou por não realizar o procedimento cirúrgico necessário. O estudo pós-operatório cuidadoso das radiografias revelou uma cabeça femoral excêntrica e evidências do implante desassociado nos tecidos moles circundantes. As radiografias após a redução fechada das luxações intraprotéticas devem ser examinadas minunciosamente.
RESUMEN
Objective To reproduce in an animal model the surgical technique of Masquelet used in the treatment of critical bone defects and to analyze the characteristics of the membrane formed around the bone cement. Methods A 10mm critical defect was created in the femoral shaft of 21 Sprague-Dawley rats. After resection of the central portion of the diaphysis, the defect was stabilized with a Kirschner wire introduced through the medullary canal and with the interposition of a bone cement spacer. After 2, 4, and 6 weeks of the surgical procedure, the animals were euthanized and evaluated on radiographs of the posterior limb regarding the size of the defect, alignment and stability of the osteosynthesis. The membranes formed around the spacer were subjected to histological analysis to assess thickness, connective tissue maturation and vascular density. Results Over time, the membranes initially made up of loose connective tissue were replaced by membranes represented by dense connective tissue, rich in thick collagen fibers. At six weeks, membrane thickness was greater (565 ± 208µm) than at four (186.9 ± 70.21µm, p = 0.0002) and two weeks (252.2 ± 55.1µm, p = 0.001). All membranes from the initial time showed foci of osteogenic differentiation that progressively reduced over time. Conclusion In addition to the structural and protective function of the membrane, its intrinsic biological characteristics can actively contribute to bone regeneration. The biological activity attributed by the presence of foci of osteogenesis confers to the membrane the potential of osteoinduction that favors the local conditions for the integration of the bone graft.
RESUMEN
Abstract Objective To reproduce in an animal model the surgical technique of Masquelet used in the treatment of critical bone defects and to analyze the characteristics of the membrane formed around the bone cement. Methods A 10mm critical defect was created in the femoral shaft of 21 Sprague-Dawley rats. After resection of the central portion of the diaphysis, the defect was stabilized with a Kirschner wire introduced through the medullary canal and with the interposition of a bone cement spacer. After 2, 4, and 6 weeks of the surgical procedure, the animals were euthanized and evaluated on radiographs of the posterior limb regarding the size of the defect, alignment and stability of the osteosynthesis. The membranes formed around the spacer were subjected to histological analysis to assess thickness, connective tissue maturation and vascular density. Results Over time, the membranes initially made up of loose connective tissue were replaced by membranes represented by dense connective tissue, rich in thick collagen fibers. At six weeks, membrane thickness was greater (565 ± 208μm) than at four (186.9 ± 70.21μm, p = 0.0002) and two weeks (252.2 ± 55.1μm, p = 0.001). All membranes from the initial time showed foci of osteogenic differentiation that progressively reduced over time. Conclusion In addition to the structural and protective function of the membrane, its intrinsic biological characteristics can actively contribute to bone regeneration. The biological activity attributed by the presence of foci of osteogenesis confers to the membrane the potential of osteoinduction that favors the local conditions for the integration of the bone graft.
Resumo Objetivo Reproduzir em modelo animal a técnica cirúrgica de Masquelet utilizada no tratamento de defeitos ósseos críticos e analisar as características da membrana formada em torno do cimento ósseo. Métodos Um defeito crítico de 10mm foi realizado na diáfise femoral de 21 ratos Sprague-Dawley. Após a ressecção da porção central da diáfise o defeito foi estabilizado com fio de Kirschner introduzido pelo canal medular e com a interposição de espaçador de cimento ósseo. Após 2, 4, e 6 semanas do procedimento cirúrgico os animais foram eutanasiados e avaliados em radiografias do membro posterior quanto ao tamanho do defeito, o alinhamento e a estabilidade da osteossíntese. As membranas formadas em torno do espaçador foram submetidas a análise histológica para avaliação da espessura, da maturação do tecido conjuntivo e da densidade vascular. Resultados Ao longo do tempo as membranas inicialmente constituídas por tecido conjuntivo frouxo foram substituídas por membranas representadas por tecido conjuntivo denso, rico em fibras colágenas espessas. Com seis semanas a espessura das membranas foi maior (565 ± 208μm) do que com quatro (186,9 ± 70,21μm, p = 0,0002) e duas semanas (252,2 ± 55,1μm, p = 0,001). Todas as membranas do tempo inicial apresentaram focos de diferenciação osteogênica que reduziram progressivamente ao longo do tempo. Conclusão Além da função estrutural e protetora da membrana, suas características biológicas intrínsecas podem contribuir ativamente para a regeneração óssea. A atividade biológica atribuída pela presença de focos de osteogênese confere à membrana potencial de osteoindução que favorece as condições locais para a integração do enxerto ósseo.