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Suture Button Syndesmosis Repair Augmented With Nonanatomic vs Anatomic AITFL Reconstruction and the Added Effect of
Mitchell R Carlson1, Evan P Shoemaker1, Caroline Chen1
1Twin Cities Orthopedics, Twin Cities Orthopedics Bioengineering Lab, Eagan, MN, USA.
Background:
Optimal fixation methods for syndesmosis injuries remain debated. The anterior-inferior tibiofibular ligament (AITFL) is critical for syndesmosis stability. The purpose of this study was to biomechanically evaluate a suture button (SB) repair of syndesmosis injuries augmented with the tails of the SB construct vs an AITFL suture augmentation, and to measure the effect of deltoid ligament repair in limiting ankle external rotation (ER).
Methods:
This controlled laboratory study used 13 cadaveric lower-leg specimens with robotic forces of 10 Nm internal and external torque under 750 N of axial compression. Each specimen underwent 8 testing surgical states: (1) native/uninjured; (2) sectioned syndesmosis with a sectioned interosseous ligament, AITFL, and posterior-inferior tibiofibular ligament; (3) fully sectioned including deep deltoid ligament; (4) syndesmosis repair with SB construct; (5) added AITFL repair using suture tails repair (SB+tails); (6) added deltoid repair with AITFL tails and syndesmosis repairs (SB+tails+deltoid repair); (7) AITFL augmentation with syndesmosis repair (SB+AITFL augmentation); and (8) additional deltoid repair with AITFL augmentation and syndesmosis repair (SB+AITFL augmentation+deltoid).
Results:
The SB+AITFL tails repair and SB+AITFL augmentation both had significantly decreased ankle ER (2.25° [1.43°, 3.06°], P < .001, and 2.34° [1.47°, 3.21°], P < .001, respectively) and decreased internal rotation (IR) (2.26° [1.38°, 3.15°], P < .001, and 2.12° [1.13°, 3.10°], P < .001, respectively) compared to the fully sectioned state. No significant differences were observed between these constructs for either ER or IR (P > .99). Additional deltoid repair significantly decreased ER (SB+tails: 0.93° [0.04°, 1.81°], P = .038, SB+ AITFL augmentation: 0.69° [0.35°, 1.02°], P < .001), but not IR (SB+tails: P > .99, SB+AITFL augmentation: P > .99).
Conclusion:
Both the SB+AITFL tails and SB+AITFL augmentation demonstrated improvements in ankle stability over SB alone; with the numbers available, no significant difference between these methods could be detected. However, no repair construct fully restored external ankle rotation to the native state. The deltoid suture repair added medial stability to both SB+AITFL tails and SB+AITFL augmentation. All absolute differences between constructs were small (fractions of a degree or millimeter), and findings should be interpreted accordingly.
Study Design:
Controlled laboratory studyClinical Relevance:This study found that, in this cadaveric model, augmenting the AITFL using either method in addition to suture button placement and open deltoid repair was associated with ankle stability approaching preinjury values across most biomechanical measures tested.