Primary stabilization of humeral shaft fractures: an experimental study of different osteosynthesis methods

OBJETIVO: Estudo experimental idealizado com o objetivo de se avaliar a estabilização primária das fraturas da diáfise umeral com três diferentes métodos de osteossíntese, representados por uma placa tipo DCP aplicada com técnica em ponte, uma síntese incomum, denominada SPS®, ainda sem similar na literatura, aplicada pela técnica em ponte, e um terceiro método constituído de uma haste intramedular com um método de bloqueio também incomum proporcionado por um parafuso cortical distalmente e por um fio do tipo Ender proximalmente. MATERIAL E MÉTODO: Vinte e um pares de úmeros humanos foram divididos em três grupos, utilizando-se um tipo de material para cada grupo, os quais foram submetidos a osteotomias, aos procedimentos de fixação e a ensaios não destrutivos de flexo-compressão e de torção, com limites de carga de 200N e de 100N, respectivamente e, num mecanismo de "crossing", foram submetidos secundariamente a novos ensaios de torção e de flexo-compressão, amparados por análise estatística. RESULTADOS: O grupo da placa DCP em ponte mostrou boa resistência às cargas aplicadas, o que também ocorreu no grupo do SPS®, que apesar de mostrar maiores índices de deflexão, apresentou grande capacidade elástica. O grupo da haste intramedular mostrou bons resultados nos ensaios de flexo-compressão, devido ao seu mecanismo de tutor, mas não demonstrou resistência às cargas de torção.OBJECTIVE: The purpose of this study was to assess primary stabilization of humeral shaft fractures using three different methods of fixation, represented by a DCP type plate, applied as a bridge plate, an uncommon synthesis material named SPS®, not previously described in literature and also used as a bridge plate, and a third type of material constituted by an intramedullary nail, with an uncommon locking provided by a distal cortical screw and a proximal Ender-type wire. MATERIAL AND METHOD: Twenty-one pairs of human humeri were divided into three groups, each using one type of material for fixation, the bones of which were osteotomized, stabilized and submitted to nondestructive flexion-compression and torsion assays up to 200 N and 100 N respectively, and, in a crossing mechanism, the groups were again submitted to other torsion and flexion-compression assays, supported by statistical analysis. RESULTS: The bridge-DCP group showed good resistance to the applied forces, similarly to the SPS® group, which, although presenting greater deflection, showed great elastic capacity. The intramedullary nail group showed good results in the flexion-compression assay due to the tutor mechanism of the intramedullary nails, but did not show resistance to the torsion forces

Femoral neck fracture following intramedullary nailing with misplacement of an end cup: report of two cases

Femoral neck fracture is an unusual complication of intramedullary fixation of a broken femur. We report on two cases of femoral neck fractures attributed to misplacement of an end cup and subsequent invasive maneuvers in an effort to remove it. Iatrogenic fractures of the femoral neck during or after intramedullary nailing are reported in the medical literature. Authors associate it with many possible technical mistakes performed during the procedure, yet no complications after missed end cup placement were noted. We suggest that the fractures described below were a consequence of injury to the vascular supply and bone stock of the initially intact femoral neck

Evidence Based Development of a Novel Lateral Fibula Plate (VariAx Fibula) Using a Real CT Bone Data Based Optimization Process During Device Development

Development of novel implants in orthopaedic trauma surgery is based on limited datasets of cadaver trials or artificial bone models. A method has been developed whereby implants can be constructed in an evidence based method founded on a large anatomic database consisting of more than 2.000 datasets of bones extracted from CT scans. The aim of this study was the development and clinical application of an anatomically pre-contoured plate for the treatment of distal fibular fractures based on the anatomical database