Minimal Invasive Fixation of Hamate Hook Fractures Through a Dorsal Percutaneous Approach Using a Mini Compression Screw: An Experimental Feasibility Study.

Abstract

Isolated fractures of the hamate hook can be treated by conservative or surgical means. Because nonoperative treatment is associated with high nonunion rates, surgical treatment with open reduction and internal fixation through a palmar approach is often preferred. The aim of this study was to refine surgical treatment of hamate hook fractures using a cannulated mini compression screw through a dorsal percutaneous approach. Artificial fractures of the hamate hook were created in five male cadaver hands under fluoroscopy. Using an ulnar approach, the hamate hook was fractured at the base (n = 3) and middle third (n = 2) of the hook using an osteotome. Each fracture was visualized by X-ray and computed tomography. Under fluoroscopy, the fracture was stabilized with a 1.1 mm K wire through a dorsal percutaneous approach which guided the introduction of a 3 mm diameter cannulated mini compression screw. The screw position was then controlled by X-ray and computed tomography. Percutaneous fixation of the fractured hook through the dorsal approach was achieved in all cases. Regardless of the fracture location, all fragments were adapted into anatomically correct positions. No displacement or disruption of the cortex of the hook was observed with central screw positioning. Minimal invasive repair of isolated hamate hook fractures through a dorsal percutaneous approach is feasible. The special properties of the cannulated mini compression screw allow optimal screw positioning and stable fixation without risk of diplacement or disruption of the hook fragment.