Biomechanical Comparison of Different Angles of K-wire Fixation Configuration for Management of Proximal Phalanx Fracture by Syringe External Fixators

Abstract

Purpose: To optimize the K-wire fixation configuration for managing proximal phalanx fractures using Syringe External Fixators.

Methods: In this biomechanical comparison study, 48 sawbone models of proximal phalanx fractures stabilized with syringe external fixators were tested across eight different K-wire configurations (Groups A–H). Configuration included parallel, nonparallel, or combined patterns at angles of 0°, 30°, or 45°. The models were underwent longitudinal compression and pull-out tensile tests. Data were analyzed using one-way analysis of variance (ANOVA) to overall group comparison and independent t-test for pairwise comparisons.

Results: Compression testing revealed that Group B (two parallel and two crossed K-wires) exhibited the highest mean ultimate strength (11.82 N). In contrast, Group D (two parallel and two crossed K-wires at varying angles) and G (four crossed K-wires) demonstrated the lowest strengths (5.49 N and 5.91 N, respectively). Although pairwise comparison between the highest- and lowest-strength groups showed a significant difference (p = 0.004), no statistically significant difference was observed across the eight groups in compression testing (p = 0.062). In pull-out testing, Group A (four parallel K-wires) displayed the highest mean ultimate strength (72.14 N), while group F (four cross-K-wires) showed the lowest (32.76 N). Pairwise comparison between these groups showed no statistically significant differences (p = 0.083). Similarly, no statistically significant difference in the pull-out tensile strength was observed among groups (p = 0.235).

Conclusions: In proximal phalanx fractures stabilized syringe external fixators, nonparallel and parallel K-wire fixation showed not significantly biomechanical different in compression and pull-out tensile testing.