Quantitative analysis of torsional stiffness in supplemental one-third tubular plate fixation in the management of isolated syndesmosis injuries: A biomechanical study

摘要

Background: Disruption of the distal tibia and fibula articulation or syndesmosis can occur without fracture, and isolated syndesmotic disruption is often treated operatively. Following syndesmotic screw removal, a period of protected weightbearing usually follows to allow the screw holes to heal. Our hypothesis was that supplementing transsyndesmotic fixation with a one-third tubular plate would potentially increase the torsional stiffness about the ankle, thus reducing the risk of fracture after screw removal and potentially allowing a faster return to weight-bearing and sport. Methods: Ten pairs of fresh frozen cadaveric specimens were divided into 2 groups. In group 1 (7 pairs), each left extremity underwent the placement, and subsequent removal, of a 4.5-mm transsyndesmotic screw in a tricortical fashion. The matching right extremity underwent the same procedure but with the addition of a one-third tubular plate, which remained in situ after screw removal. In group 2 (3 pairs), the left specimens had a screw placed and removed while the right limbs remained intact. All specimens were tested under an axial preload and a torsional load until failure. Results: In group 1, the results demonstrated an increase in torsional stiffness in 5 of 7 specimens with supplemental fixation of a one-third tubular plate. In group 2, the presence of the screw hole alone reduced the torsional stiffness in all specimens tested when compared with intact specimens. However, neither of these differences were statistically significant. Conclusion: From this study, we can conclude that the use of supplementary one-third tubular plate fixation demonstrated a trend toward increasing the torsional stiffness following transsyndesmotic screw removal. Clinical Relevance: We believe the trend toward improved stiffness justifies the continued use of our technique, although further studies are necessary to confirm it.