Initial promising results of the dynamic locking blade plate, a new implant for the fixation of intracapsular hip fractures: results of a pilot study.

INTRODUCTION: The osteosynthesis of intracapsular hip fractures results in a 19-48% failure rate. Only when the anatomical reduction is secured by stable fixation, revascularisation of the femoral head can take place and the fracture can heal by primary osteonal reconstruction. The common implants lack rotational and/or angular stability. Also the relative large volume of the implants within the femoral head compromises the (re)vascularisation. The combination of an anatomical reduction and a low volume, dynamic implant, providing angular and rotational stability seem to be crucial factors in the treatment of intracapsular hip fractures. This assumption formed the starting point for the development of the dynamic locking blade plate (DLBP), a new implant for the internal fixation of intracapsular hip fractures. This report describes the first clinical results of the new implant. PATIENTS AND METHODS: Internal fixation with the DLBP was performed in 25 consecutive patients with an intracapsular hip fracture within 24 h from admission. Failure of fixation, due to non-union, avascular necrosis, implant failure or secondary displacement of the fracture, was the primary outcome measurer. Functional outcome was assessed by the Harris Hip Score. RESULTS: Following internal fixation of intracapsular hip fractures with the DLBP, a failure rate of 2 out of 25 patients and excellent functional results were seen after a follow-up of more than 2 years. CONCLUSION: The initial clinical results of the DLBP are promising and justify the start of a randomised controlled trial.

The dynamic locking blade plate, a new implant for intracapsular hip fractures: biomechanical comparison with the sliding hip screw and Twin Hook.

Internal fixation of intracapsular hip fractures results in a high failure rate with non-union and avascular necrosis being the two most important complications. In order to prevent these possible complications treatment should consist of an anatomical reduction and stable fixation by insertion of a low volume, dynamic implant, providing angular and rotational stability to the femoral head. According to these principles a new implant, the dynamic locking blade plate (DLBP) was designed for the fixation of intracapsular hip fractures. We performed a biomechanical analysis in synthetic bone to compare the rotational stability and cut out resistance of the DLBP with a conventional sliding hip screw (SHS) and the more recently developed Twin Hook. The rotational stability of the DLBP proved to be three times higher than the rotational stability of a SHS and two times higher than the Twin Hook. There was no major difference in cut out resistance between the different implants. The design of the DLBP and possible advantages with regard to the healing of an intracapsular hip fracture are discussed.

A new orthotic device in the non-operative treatment of idiopathic scoliosis.

A transverse force system, consisting of an anterior progression force counteracted by a posterior force and torque, acts on the vertebrae of a scoliotic spine. The aim of the newly introduced TriaC brace is to reverse this transverse force pattern by externally applied and constantly present orthotic forces. In the frontal plane the force system in the TriaC brace is in accordance with the force system of the conventional braces. However, in the sagittal plane the force system acts only in the thoracic region. As a result, there is no pelvic tilt, and it provides flexibility without affecting the correction forces during body motion. In the current preliminary study it is demonstrated that the brace prevents further progression of the Cobb angle and axial rotation in idiopathic scoliosis. The new brace has the added advantage of comfort for the wearer, and it offers a better cosmetic appearance, as well as, potentially, a better compliance.

A biomechanical analysis of the vertebral and rib deformities in structural scoliosis.

Although the structural changes occurring in the scoliotic spine have been reported as early as the 19th century, the descriptions and biomechanical explanations have not always been complete and consistent. In this study, three-dimensionally rendered CT images of two human skeletons with a scoliotic deformity and two patients with serious scoliosis were used to describe the intrinsic vertebral and rib deformities. The pattern of structural deformities was found to be consistent. Apart from the wedge deformation of the apical vertebrae, a rotation deformity was found in the transversal plane between the vertebral body and the posterior complex: the vertebral body was maximally rotated towards the convexity of the scoliotic curve, whereas the tip of the spinous process was pointed to posterior. The rib deformities at the convex side of the scoliotic curve showed an increased angulation of the rib at the posterior angle, whereas the rib curve on the concave side was flattened. The observed vertebral deformities suggest that these are caused by bone remodelling processes due to forces in the anterior spinal column, which drive the apical vertebral body out of the midline, whereas forces of the musculo-ligamentous structures at the posterior side of the spinal column attempt to minimize the deviations and rotations of the vertebrae. The demonstrated rib deformities suggest an adaptation to forces imposed by the scoliotic spine.