Long dorsal "Y-shaped" plate for distal diaphyseal humeral fractures

Designing of a Distal Humerus Anatomical Biplanar Locking Fixation Plate

Aims

For anatomical reduction and stable bi-columnar fixation with two separate plates, to allow early joint motion is presently the treatment of choice for distal humerus fractures. Although there is a wide range of implants available for distal humerus fractures but none provides adequate fixation in distal fragment, particularly in very distal and osteoporotic fractures. The present study was conducted to overcome such problems and develop a single pre-contoured locking plate, which can match the anatomy of different sizes of distal humerus, with maximum options of screw placement in distal fragment, preferably in multiple angular planes.

Methods

The present study describes about the development of an innovative Y-shape anatomical locking plate for distal humerus fractures, after a detailed morphological study of lower end of humerus in a large number of cadaveric bones. This plate has been designed in such a way to provide wide range of distal fixation options in both coronal as well as sagittal planes.

Discussion

The proposed plate is anatomically designed, pre-contoured locking plate construct requiring minimum further molding to match the anatomy of distal humerus in different bone sizes. All the screws are contributing to the stability of the construct. It gives wide range of screw placement options in distal fragment in both coronal and sagittal planes. It allows the surgeon to put long intercondylar screw through the plate both from medial and lateral sides.

Biomechanical analysis of a novel Y-plate designed for the treatment of extraarticular distal humerus fractures

Adult distal humerus fractures are infrequent, yet they account for one-third of all humerus fractures. For the treatment of comminuted and osteoporotic fractures, locking plates are claimed to be biomechanically superior to alternative internal fixing techniques. Treatment remains difficult despite recent advancements and the use of locking plates due to frequent comminution, low bone quality, and limited healing ability in osteoporotic bone. An optimal design of the newly constructed plate and the control model were selected. The biomechanical characteristics of non-osteoporotic and osteoporotic synthetic bone were compared on six models. The biomechanical properties of the new plate were tested and compared on 54 osteoporotic synthetic humerus models. The control models were reconstructive and parallel LCPs. The tests were carried out under static and dynamic axial, lateral and bending loads. Fracture displacements were measured by optical measuring system Aramis. The test model is significantly stiffer for lateral load (p = 0.0007) and for bending load at the moment of model failure (p = 0.0002), while for axial load the LCP model showed greater stiffness (p = 0.0017). During lateral dynamic loading, all three LCP models broke and there was a significant difference compared to the test model (p = 0.0125). The LCP model is dynamically significantly more durable under axial load, while the largest displacements were recorded with the test model (p = 0.029). The displacements induced by all three loads are within the limits that fulfil the parameters of appropriate biomechanical stability. A novel locking plate for extra-articular distal humerus fractures may provide an alternative to the traditional two-plate.