Analysis of Three Types of Fixation of the Weil Osteotomy

This study assessed 3 methods of fixation for the Weil osteotomy. A total of 40 bone models were divided equally into 4 groups: a control group consisting of intact lesser rays; and Weil osteotomies that were fixated with 2 crossed Kirschner wires (0.045-in K-wires), 2.0-mm cortical screws, or cannulated 2.4-mm cortical screws. Each specimen was stressed in a computer-controlled hydraulic tensile testing machine, and maximum load, energy to failure, and stiffness were recorded. The following mean load to failure measurements were found: control, 62.9 Newtons (N); K-wire, 22.9 N; cannulated screw, 31.3 N; and noncannulated screw, 19.9 N. There was no statistical difference among the 3 groups of fixation methods in terms of the maximum load. The mean energy to failure of the control group was 326 joule (J); K-wire, 79 J; cannulated screw, 163 J; and noncannulated screw, 66 J. The cannulated screw generated a statistically greater amount of energy at failure than the noncannulated screw (P < .05). The mean structural stiffness of the control group was 7.3 N/mm; K-wire, 2.8 N/mm; cannulated screw 3.3 N/mm; and noncannulated screw, 3.2 N/mm. There was no statistical difference in structural stiffness among the 3 groups of fixation methods. The results indicated a trend toward better biomechanical stability with the 2.4-mm cannulated screw than the 2.0-mm noncannulated screw for fixation of the Weil osteotomy.

Key words:  Weil osteotomy , metatarsal osteotomy , lesser metatarsalgia , screw fixation