Abstract
Category:
Trauma; Midfoot/Forefoot
Introduction/Purpose:
Ligamentous Lisfranc injuries represent a devastating injury complex to the midfoot. Treatment with screw fixation across the first tarsometatarsal (TMT) joint and across the first cuneiform-second metatarsal joint (C1-M2) joint has been described, however there are no studies examining the utility of adding a transcuneiform screw across the first cuneiform-second cuneiform (C1-C2) joint. The purpose of this study was to evaluate the effectiveness of transcuneiform screws at minimizing interosseous displacement in ligamentous Lisfranc injuries when added to traditional Lisfranc screw fixation.
Methods:
Unstable ligamentous Lisfranc injuries were created on ten fresh-frozen cadaveric specimens by sectioning the interosseous ligaments in a manner that has been described previously. Simulated weight bearing stress (222.4 N) as well as manual abduction and adduction stresses were applied to each specimen and interosseous displacement at the C1-C2 and C1-M2 joints was measured on gross images using calibration with 2mm radiographic marker balls. These measurements were performed initially with no screws, followed by with two-screw fixation across the C1-M2 joint and the first TMT joint, and finally with a third transcuneiform screw across the C1-C2 joint. The images were analyzed and statistical analysis was performed to determine the effect of transcuneiform fixation on interosseous displacement at the C1-C2 and C1-M2 joints.
Results:
The addition of transcuneiform screw fixation to traditional two-screw fixation decreased the amount of interosseous widening at C1-M2 by an average of 0.03mm at rest, 0.39mm during abduction stress, 0.21mm during adduction stress, and 0.19mm during weight bearing. The interosseous widening at C1-C2 decreased with the addition of transcuneiform fixation by an average of 0.30mm at rest, 0.11mm during abduction stress, 0.18mm during adduction stress, and 0.05mm during weight bearing. Of these findings, only the change in interosseous widening at C1-M2 during abduction stress demonstrated a statistically significant difference (p=0.031) with the addition of the transcuneiform screw compared to traditional two-screw fixation.
Conclusion:
The addition of transcuneiform screw fixation in ligamentous lisfranc injuries allows less interosseous widening at the C1-M2 joint during abduction stress when compared to traditional two-screw Lisfranc fixation. Further research is required to determine the clinical significance of fixing the transcuneiform joint in Lisfranc injuries and whether or not this potential reduction in motion affects outcomes such as pain control, healing, or function.