Radiographic Parameters to Predict Union After Volar Percutaneous Fixation of Herbert Type B1 and B2 Scaphoid Fractures

Abstract

Purpose To study the angle of screw placement in relation to the scaphoid fracture plane and its effect on union after percutaneous fixation of scaphoid waist fractures. Methods Twenty-four consecutive scaphoid waist fractures were retrospectively evaluated for the orientation of screws in relation to the fracture plane using a method in which the sum-of-smaller angles (SSA) in three different radiographs were used to correlate with time to fracture union. Results All but one patient achieved union after percutaneous fixation of the scaphoid. One other patient required revision surgery within the study period for inadequate fixation. A shortened time to union was significantly correlated to larger sums of small angles (SSA). Conclusion SSA may be a reasonable predictor of union after percutaneous fixation of scaphoid waist fracture. It can be reliably calculated using plain radiographs. An SSA of 190 degrees or more correlated with union by eight weeks post operatively. Level of evidence Prognostic Retrospective level IV

Ideal Starting Point and Trajectory of a Screw for the Dorsal Approach to Scaphoid Fractures

“…9,13 In addition, screws perpendicular to the fracture site allow for a larger fracture area available for apposition and blood flow, 14 and had no difference in load to failure or cyclical loading of the screw, even when the screw was shorter. 10 Most recently, a clinical study by Mahmoud et al 11 showed that screws placed more perpendicular to the scaphoid fracture plane had a shorter time to union as well.…”