[Primary stability of proximal interphalangeal joint arthrodesis: an in-vitro comparison of intraosseous wiring with and without a transverse Kirschner wire].

BACKGROUND: Arthrodesis can be considered the fastest and safest surgical treatment for degenerative destruction of the proximal interphalangeal joint. For this procedure, a variety of surgical strategies have been described. Protocols for compression arthrodesis by intraosseous wiring are known to have the best outcomes. Biomechanical effects of reinforcing the arthrodesis using Kirschner wires have been controversially discussed.

PURPOSE: This study aims to compare these two procedures with respect to primary stability under physiological stress in vitro.

MATERIAL AND METHODS: In total, 72 fingers from 9 pairs of hands of formalin-ethanol fixed body donors were used for the study. To achieve comparability, these were chirally matched. After arthrodesis, primary stability was evaluated during a two-point application of rotational, abducting and extending forces. Peak torque values acting on the arthrodesis were defined as the breaking load and compared by a paired Student t-test.

RESULTS AND CONCLUSION: Kirschner-wire reinforced arthrodeses showed significantly higher breaking loads for extension and abduction than those within the control group. Nevertheless, both methods achieved breaking loads above the physiological load level in the area of the proximal interphalangeal joint. Even though sole intraosseous wiring can be considered biomechanically adequate, we suggest reinforcement using a transverse Kirschner wire to enhance the primary stability.