Single versus dual elastic nails for closed reduction and antegrade intramedullary nailing of displaced fifth metacarpal neck fractures

Abstract

Closed reduction and internal fixation with antegrade intramedullary nails is a feasible and effective treatment for displaced fifth metacarpal neck fractures (FMNFs). The present study aimed to compare clinical and radiological outcomes in patients with displaced FMNFs after treatment with single or dual antegrade elastic intramedullary nails (AEIMNs). Thirty-three patients were treated with a single 2.0 mm AEIMN and 34 patients were treated with two 1.5 mm AEIMNs. Clinical and radiological outcomes included grip strength, active range of motion (ROM), active flexion and extension of the fifth metacarpophalangeal (MCP) joint, dorsal angulation loss, and metacarpal shortening of the fifth metacarpal at 12 months after treatment. No significant difference was observed between the two groups with respect to grip strength, ROM or flexion of the fifth MCP joint. The average values of dorsal angulation loss, metacarpal shortening, and extension of the fifth MCP joint of the dual nails group were better than those of the single nail group (dorsal angulation loss, 2.79 ± 1.93° vs. 4.05 ± 1.59°, P = 0.009; metacarpal shortening, 1.66 ± 0.80 mm vs. 2.12 ± 0.88 mm, P = 0.028; extension of the fifth MCP joint, 7.71 ± 4.43° vs. 4.82 ± 4.09°, P = 0.012). In conclusion, dual AEIMNs fixation provided better MCP extension and radiological outcomes than single AEIMN fixation.

Figure 1

Schematic illustration of an FMNF fixed with single AEIMN on lateral view (A) and anteroposterior view (B), and fixed with dual AEIMNs on lateral view (C) and anteroposterior view (D).

Figure 2

Clinical case of an FMNF treated by single AEIMN. Preoperative oblique view radiograph (A). Postoperative radiographs showing a good reduction of the fracture (B). Radiograph at 8 weeks after the operation shows union of the fracture (C).

Figure 3

Clinical case of an FMNF treated by dual AEIMNs. Preoperative oblique view radiograph (A). Intraoperative photograph showing two incisions in the metacarpal base (B). Intraoperative fluoroscopy (C). Postoperative radiographs showing good reduction of the fracture on the anteroposterior view (D) and oblique view (E). Radiograph at 8 weeks after the operation shows union of the fracture (F, G). Radiograph at 6 months after removal of the nails (H, I). Photographs of the hand in flexion (J) and extension (K) at 12 months after operation.

Figure 4

Methods of radiological measurements. Dorsal angulation was defined as an acute angle (a) between the line drawn on the dorsal cortex of the fifth metacarpal shaft and the second line on the dorsal cortex of the fifth metacarpal head/neck (A). The metacarpal length was defined as the length between the most distal articular surface of the fifth metacarpal head (b) and the mid-point (c) of both corners of the fifth metacarpal base (B).