A Comparative Study of Tensile Strength of Three Operative Fixation Techniques for Metacarpal Shaft Fractures in Adults: A Cadaver Study

BACKGROUND: We sought to estimate the ultimate tensile strength after metacarpal shaft fracture repair in adults using three operative fixation methods: plate fixation, Kirschner wire (K-wire) fixation, and intramedullary headless compression screw fixation. We also compared the advantages and disadvantages of each operative technique. METHODS: We acquired 30 metacarpal bones from four Korean adult cadavers without trauma, operative history, or deformities. The 30 metacarpal bones were divided into ten groups consisting of three metacarpal bones each with matching sizes and lengths. They were fractured, reduced, and fixed with plate and screws, K-wires, or headless compression screws. We performed force testing, collected ultimate tensile strength data, and created a stress-strain graph. RESULTS: The ultimate tensile strength of ten groups according to the fixation method was as follows: late and screw fixation, 246.1 N (range, 175.3 to 452.4 N); K-wire fixation, 134.6 N (62.7 to 175.0 N); and intramedullary headless compression screw fixation, 181.2 N (119.2 to 211.7 N). The median tensile strength of each fixation method was significantly different. In addition, the post-hoc test showed significant difference between the plate and screw fixation and K-wire fixation, between the headless compression screw fixation and K-wire fixation, and between the headless compression screw fixation and plate and screw fixation. CONCLUSIONS: The tensile strength median values decreased in the following order showing significant differences among the fixation methods: plate and screw fixation, headless compression screw fixation, K-wire fixation. Significant differences were also observed between the plate and screw fixation and K-wire fixation, between the headless compression screw fixation and K-wire fixation, and between the headless compression screw fixation and plate and screw fixation.