In our study, suture-button fixation performed using the TightRope for ankle syndesmosis injury was found to be an effective modality, which resulted in a significant decrease in TFCS and MCS and a significant increase in TFO after the surgery, with acceptable alignment. However, postoperative measurements revealed that MCS was significantly larger in the Weber-C group than in the other 2 groups. Moreover, when final follow-up values were compared with postoperative values, we found a significant increase in TFCS and a decrease in TFO in the Weber-C group; however, the mean values of final follow-up TFCS and TFO were in the acceptable range.
In the Weber-C group, 12 patients (43%) had MCS greater than 4 mm after index surgery, 7 patients (25%) had TFO lesser than 6 mm, and 6 patients (21%) had TFCS greater than 6 mm. When postoperative measurements were compared between the groups, MCS was found to be significantly greater in the Weber-C group than in the other groups. The same results were also noted for final follow-up measurements, with the mean MCS value being slightly greater in the Weber-C group than in other groups.
To summarize the findings, the preoperative and immediate postoperative MCS were wider in Weber-C type fractures than in other types of injuries and malreduction in MCS was more common in Weber-C type fractures when compared with different injury mechanisms. Alternatively, rediastasis was more likely to occur in Weber-C type fractures after weight bearing by the affected limb. These findings may be attributed to higher force applied to the affected ankle at the time of injury, greater initial displacement, and more commonly to fracture dislocation of the ankle. To date, various cohort studies have supported the use of suture-button fixation because it provides sufficient longevity and comparable outcomes as syndesmotic screw fixation (9, 11, 15, 17, 26–28). However, Peterson et al. retrospectively reviewed 59 patients who underwent open reduction internal fixation of ankle syndesmosis with suture-button and found that the distance between the buttons increased with an average of 1.1 mm from immediate postoperative to final follow-up (20), which indicates widening of syndesmosis after weight bearing. However, the study did not focus on differences between injury mechanisms. In the study by Boden et al. (29) and Michelson and Waldman (30), the importance of deltoid ligament integrity on syndesmosis stability were emphasized. In the study, isolated sectioning of the interosseous ligament had no significant effect on syndesmotic stability, whereas sectioning of the deltoid ligament resulted in increased external rotation of the foot (2, 30). Our results indicated that more deltoid ligament tears in Weber-C type fractures and more commonly malreduced MCS or inversed deltoid ligament after index surgery, causing instability of the syndesmosis. Thus, more rigid fixation may be needed for syndesmotic stability in Weber-C type fractures.
The implant removal rate (22%) was higher in our study than in previous studies. Among the 14 patients who underwent implant removal, 7 underwent implant removal along with the removal of the lateral malleolar plate, whereas the remaining 7 underwent removal of the suture-button implants only. Furthermore, only 2 patients experienced severe soft tissue irritation and abscess formation. Knot irritation (19%) and surgical site infection (8%) were believed to be the most common complications related to this technique (14–17). Naqvi et al reported an implant removal rate of 16.7% with the standard technique and 0% with the modified technique of the suture-button. In the modified technique, 1 cm of the free ends of Fiberwire were buried in the recess behind the fibula and then were covered with the periosteum (15). Storey et al reported a similar technique to prevent skin irritation and abscess formation (16).
This study has several limitations. This retrospective study used only plain films for interpreting the button placement and syndesmosis distance and lacked a subjective functional score for outcome evaluation. Low numbers of our patient cohort, especially in the pure syndesmosis group, is also a major limitation of the study. Further large-scale prospective studies may be required for more definite interpretation of the current study results. A longer follow-up period is also required to observe the possibility of late diastasis and osteoarthritis.