Volar Lunate Facet Fractures of the Distal Radius: Fracture Mapping Using 3D CT Scans

Assessment and Fixation Strategies for the Unstable Volar Lunate Facet

Surgical fixation of unstable distal radius fractures greatly depends on the characteristics of the fracture pattern. Intra-articular fractures of the distal radius often involve several key fragments that require adequate reduction and fixation. The volar lunate facet is just one of those fragments, making up the critical corner of the distal radius articular surface and serving as the keystone to both the radiocarpal and distal radioulnar joints. Satisfactory reduction and stabilization of this fragment can be very challenging, and failure of this can lead to volar subluxation of the carpus, distal radioulnar incongruence with resultant instability, and ultimately poor patient outcomes. This review aims to highlight the relevant anatomy and proper imaging crucial to the understanding and evaluation of distal radius fractures involving an unstable volar lunate facet fragment. In addition, we highlight steps in obtaining adequate exposure of the critical corner and numerous fixation strategies that can assist to optimally stabilize it.

Progress of fracture mapping technology based on CT three-dimensional reconstruction

Fracture Mapping is a new technology developed in recent years. This technology visually representing the morphology of fractures by overlaying fracture lines from multiple fracture models onto a standard model through three-dimensional reconstruction. Fracture mapping has been widely used in acetabular fracture, proximal humerus fractures, Pilon fracture, tibial plateau fractures, and so on. This technology provides a new research method for the diagnosis, classification, treatment selection, internal fixation design, and statistical analysis of common fracture sites. In addition, the fracture map can also provide a theoretical basis for the establishment of a biomechanical standardized fracture model. Herein, we reviewed various methods and the most advanced techniques for fracture mapping, and to discuss the issues existing in fracture mapping techniques, which will help in designing future studies that are closer to the ideal. Moreover, we outlined the fracture morphology features of fractures in various parts of the body, and discuss the implications of these fracture mapping studies for fracture treatment, thereby providing reference for research and clinical decision-making on bone and joint injuries to improve patient prognosis.

Novel hook plate for radial semilunar lip facet fragment fixation: a finite element analysis

Intra-articular fractures of the distal radius require anatomical reduction and stable fixation. When the fracture encompasses the articular facet of the bone, maintaining the reduction is challenging due to the fragment's size and high instability. While specific implants have been developed to fix this fragment, their effectives have been limited. This study evaluates the mechanical performance of a novel hook plate conceived to stabilize the small fragment of the semilunar facet of the radius in non-osteoporotic bones. A simulated lunate facet fracture was created in an adult radius in a virtual model, and a modification of a hook plate was developed using computer-aided design (CAD). Two groups were established for the finite element method (FEM) simulation: a control group (standard plate Medartis™ (Switzerland, A-5500.23) and an angled plate with hooks set at 60º, 90º and 120º. In the FEM simulation, an axial load of 100 N was applied in the Z-axis direction on the fragment. Fracture displacement along the Z axis was more pronounced in the control model (0.32 mm) and less in the angled models, ranging from 0.22 to 0.28 mm. Notably, the plate with a 90° angle showed a more effective reduction in fragment displacement. The distribution of stresses in the system showed the highest levels of stress in the control group (59.31 MPa), followed by the subgroup with a 60° angle (55.78 MPa).In the side view, the control model showed a higher concentration of stresses (59.74 MPa), while the model with a 90° angle showed a lower value of stresses (18.87 MPa). Critical stress regions were identified in the bolts of the control and 120° models (59.47 MPa and 57.64 MPa, respectively). However, in the 90° model, no critical regions were observed in the bolts, which showed lower stress values, reaching 26.33 MPa. In the bone, the greatest concentration of stress occurred in the region where the plate was anchored. Our results showed that the 90° hook plate had a superior mechanical performance in fixing simulate lunate facet fractures at the distal radius. This angle led to minor displacements and minimized stress concentrations in the hardware, thus contributing to enhance the stability of this specific fracture.

Management of isolated volar lunate facet fractures of the distal radius

Distal radius fractures are among the most common fractures treated globally. Consideration of the mechanism of injury and careful radiographic assessment contributes to appropriate management of these injuries in isolation or jointly with other fractures or injuries affecting the wrist joint. Treatment options can range from non-operative management to a variety of fixation techniques. Interest in the distal radius fractures was renewed as open reduction and monoblock volar locking plate fixation became the preferred contemporary treatment in the last few decades. Isolated volar lunate facet (VLF) fractures are uncommon. However, the stability of the entire carpus may be compromised with fractures of the volar marginal rim. Inadequately or improperly treated fractures of the VLF can lead to significant long-term complications. A critical approach to this unique fracture pattern's evaluation, management, and surgical fixation is paramount for successful and reproducible outcomes in stability and durability.