Analysis of the interface formed among the poli (viniilidene) fluoride (piezoelectric and non-piezoelectric) and the bone tissue of rats

The objective of this study was to evaluate the interface formed between the poli (viniilidene) fluoride (PVDF-piezoelectric and non-piezoelectric) and cap rats' bone tissue. Twenty tubes of PVDF [P (VDF-TrFE)] piezoelectric, (d3h = 2,5 pC/N and capacitance 800 pF/m), and twenty tubes of non-piezoelectric PVDF were implanted in the intercondilian notch of the left femur of 40 rats. The animals of both groups were subdivided in four subgroups, followed up for 7 days, 3, 6 and 12 weeks. The interface found between bone and tubes was studied by conventional optical microscopy (MOC) (n=28) and by backscattered electronic scanning microscopy (MEV) (n=12). Bone tissue growth was observed inside the tubes of piezoelectric PVDF followed up during 12 weeks, both by MOC and by MEV backscattering. The results indicate that the piezoelectric effect had an important role in the new bone tissue formation inside the piezoelectric tubes. Probably, that bone formation was a result from the electrets effect or from micro deformations produced in the piezoelectric tubes, due to the intra-articular pressure variation on the knee movement during gait.O objetivo deste estudo foi analisar a interface formada entre o polifluoreto de vinilideno (PVDF - piezelétrico e não piezelétrico) e o tecido ósseo do rato. Foram implantados em 40 ratos, na região intercondiliana do fêmur esquerdo, vinte tubos de PVDF [P(VDF-TrFE)] piezelétricos, (d3h = 2,5 pC/N e capacitância 800 pF/m), e vinte tubos de PVDF não piezelétricos. Os animais de ambos os grupos foram subdivididos em quatro subgrupos, seguidos por 7 dias, 3, 6 e 12 semanas. A interface formada pelos tubos com o tecido ósseo foi estudada por microscopia óptica convencional (MOC) (n=28) e pela microscopia eletrônica de varredura (MEV) por retroespalhamento (n=12). No interior dos tubos de PVDF piezelétricos seguidos por 12 semanas foi constatado, tanto pela MOC como pela MEV por retroespalhamento, crescimento de tecido ósseo. Os resultados indicam que a piezeletricidade teve papel importante na neoformação do tecido ósseo no interior dos tubos piezelétricos. Provavelmente, essa formação óssea foi decorrente ou do efeito eletreto, ou das microdeformações produzidas nos tubos piezelétricos, devido à variação da pressão intra articular do joelho durante a marcha.16016

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Thinking on orthopedics and traumatology research methodology

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Comparing The In Vitro Stiffness Of Straight-dcp, Wave-dcp, And Lcp Bone Plates For Femoral Osteosynthesis.

The objective of this study was to compare the Locking Compression Plate (LCP) with the more cost-effective straight-dynamic compression plate (DCP) and wave-DCPs by testing in vitro the effects of plate stiffness on different types of diaphyseal femur fractures (A, B, and C, according to AO classification). The bending structural stiffness of each plate was obtained from four-point bending tests according to ASTM F382-99(2008). The plate systems were tested by applying compression/bending in different osteosynthesis simulation models using wooden rods to simulate the fractured bone fragments. Kruskal-Wallis test showed no significant difference in the bending structural stiffness between the three plate models. Rank-transformed two-way ANOVA showed significant influence of plate type, fracture type, and interaction plate versus fracture on the stiffness of the montages. The straight-DCP produced the most stable model for types B and C fractures, which makes its use advantageous for complex nonosteoporotic fractures that require minimizing focal mobility, whereas no difference was found for type A fracture. Our results indicated that DCPs, in straight or wave form, can provide adequate biomechanical properties for fixing diaphyseal femoral fractures in cases where more modern osteosynthesis systems are cost restrictive.201330875

Survival rates of the HIMEX extensible nail in the treatment of children with osteogenesis imperfecta

OBJECTIVE: To evaluate the performance of an extensible nail with hooks, named HIMEX, in osteogenesis imperfecta (OI) deformities. METHODS: All child patients were operated on with HIMEX from 1990 to 2004. The number of fractures, reappearance of deformities, improvement of motor development before and after the use of HIMEX, and the incidence of the migration and nail survival were compared. RESULTS: Fourteen patients, with ages from 2 to 18 years, including 8 females, underwent 46 procedures, 39 primary and 7 re-operations. The average age at the first fracture was 148.21 days, and there was an average of 42.6 fractures per patient prior to HIMEX placement. Of the forty-six bones affected, 28 were femurs and 18 were tibias. Average follow-up care lasted 80.21±36.71 months. There was a statistically significant decrease (0.78) in the number of fractures per patient and an improvement in walking in seven of the fourteen patients. Revision occurred in 18% of patients and migration of the nail occurred in 12% (5/39). Eighty percent of the nails remained in situ until 108 months, with femoral procedures lasting significantly longer than tibial procedures. The type of OI and the age at the procedure did not significantly affect the incidence of revision. CONCLUSION: HIMEX significantly reduced the number of fractures, presenting lower incidence of migration and higher survival rates than those described in literature.OBJETIVO: avaliar o desempenho da haste extensível ancorada por ganchos (HIMEX) em deformidades da osteogênese imperfeita (OI). MÉTODOS: Todas as crianças operadas com HIMEX entre 1990 - 2004. Foi comparado o número de fraturas, reaparecimento de deformidades e capacidade de deambulação antes e após a HIMEX; incidência de migração e sobrevida da haste por curvas de sobrevivência. RESULTADOS: 14 pacientes (2 a 18 anos), oito do sexo feminino, incluindo 46 procedimentos, 39 primários e sete re-operações. Idade média na primeira fratura de 148,21 dias e média de 42,6 fraturas/paciente pré colocação da HIMEX. Dos 46 procedimentos, 28 no fêmur e 18 na tíbia. Tempo médio de seguimento de 80,21 ± 36,71 meses. Houve diminuição significativa de fraturas/paciente (0,78) e melhora na deambulação em sete dos 14 pacientes. Porcentagem de re-operação de 18% e migração do implante em 12% (05/39). 80 % dos implantes in situ até 108 meses. Implantes na tíbia tiveram sobrevida significativamente menor que os do fêmur. O tipo da OI e a idade na época da cirurgia não influenciaram significativamente a incidência de re-operação. CONCLUSÃO: A HIMEX levou à redução significativa no número de fraturas, incidência menor de migração e sobrevida maior da haste do que a referida na literatura.34334

Minimal invasive ostheosintesis for treatment of diaphiseal transverse humeral shaft fractures

OBJECTIVE:To evaluate patients with transverse fractures of the shaft of the humerus treated with indirect reduction and internal fixation with plate and screws through minimally invasive technique.METHODS:Inclusion criteria were adult patients with transverse diaphyseal fractures of the humerus closed, isolated or not occurring within 15 days of the initial trauma. Exclusion criteria were patients with compound fractures.RESULTS:In two patients, proximal screw loosening occurred, however, the fractures consolidated in the same mean time as the rest of the series. Consolidation with up to 5 degrees of varus occurred in five cases and extension deficit was observed in the patient with olecranon fracture treated with tension band, which was not considered as a complication. There was no recurrence of infection or iatrogenic radial nerve injury.CONCLUSION:It can be concluded that minimally invasive osteosynthesis with bridge plate can be considered a safe and effective option for the treatment of transverse fractures of the humeral shaft.Level of Evidence III, Therapeutic Study.Universidade de Campinas Hospital das Clinicas Department of Orthopedics and TraumatologySwedish Medical CenterUniversidade Federal de São Paulo (UNIFESP) Departament of Orthopedics and TraumatologyUNIFESP, Departament of Orthopedics and TraumatologySciEL

Acoustic Therapy as Mechanical Stimulation of Osteogenesis

Acoustic therapy is a branch of mechanotherapy. This modality of treatment can be used for osteogenesis-related orthopaedic disorders. Because bone cells are responsive to acoustic forces, specially designed devices were developed to generate acoustic forces in the form of low-intensity pulsed ultrasound, extracorporeal shock waves or radial pressure waves. With the developed devices, it became possible to provide patients an alternative, or adjunctive, treatment for pathologies involving bone homeostasis, that is, the balance of bone formation and bone resorption. The so-called acoustic therapy (low-intensity pulsed ultrasound stimulation, LIPUS; extracorporeal shock wave therapy, ESWT; and radial pressure wave therapy, RPWT) acts through physical phenomena produced when acoustic waves are transmitted into living tissue and converted to biological reactions, thereby activating signalling pathways that drive a cellular response in favour of osteogenesis. In this chapter, an extensive review of the literature was performed to provide the reader the “state of the art” about the physical phenomena, molecular events and clinical uses of acoustic forces for osteogenesis-related orthopaedics disorders

Lower limb amputation in children: report and experience in 21 cases

It is reported the experience in 21 patients, average age of 6 years old, who were submitted to 26 lower limb amputation due to congenital malformation (14), infection (6) and others. It is discussed the procedures, complications, advantages and disadvantages of each amputation level. It is concluded that amputation in children is still an option to be considered, mainly for allowing the patent a rapid recovery both functional and social.Os autores apresentam os resultados de 21 pacientes, com idade média de 6 anos, submetidos à 26 amputações do membro inferior por malformações congênitas (14), infecções (06) e outras. Discute-se os procedimentos, as complicações, as vantagens e desvantagens de cada nível de amputação. Concluem que a amputação na criança continua sendo uma opção a ser considerada, principalmente por propiciar rápida recuperação funcional e social do paciente.61