Screw Length Optimization of a Volar Locking Plate Using Three Dimensional Preoperative Planning in Distal Radius Fractures.

Abstract

A three-dimensional (3D) digital pre-operative planning system for the osteosynthesis of distal radius fracture was developed. The objective of this study was to evaluate screw choices for three-dimensional (3D) digital pre-operative planning of osteosynthesis of distal radius fractures and to compare with the screw choices for the conventional method. Distal radius fracture patients who underwent osteosynthesis using volar locking plates were evaluated. Thirty wrists in the plan group utilized 3D preoperative planning, and nineteen wrists in the control group utilized conventional preoperative assessment. In the plan group, the 3D preoperative planning was performed prior to surgery. The reduction was simulated with 3D image, and the implant choice/placement also simulated on the 3D image. In the control group, standard preoperative planning was performed using posterior-anterior and lateral view radiographs, and CT scan. After the planning, osteosynthesis was performed. During the surgery, the operator performed the reduction and the placement of the plate while comparing images between the pre-operative plan and fluoroscopy. The distal screw lengths and the anteroposterior diameter of the radius along the axis of the distal screws were measured. The ratios of the screw length and radius diameter were evaluated. The screw/radius ratios within the range of 0.75-1.00 were considered appropriate. The screw choices less than 0.75, or greater than 1.00 were considered inappropriate. The rate of appropriate screw choices were compared between plan and control groups. The results of appropriate screw choices were 86.1% and 74.8% in the plan group and the control group, respectively. The inappropriate screw choices were 14.0% and 25.2% in the plan group and the control group, respectively. The three-dimensional planning significantly increased appropriate screw choices compared to the conventional planning (p < 0.05). Three-dimensional digital preoperative planning is useful for the optimization of screw lengths in osteosynthesis of distal radius fractures.