Suture-button Versus Screw Fixation in Adolescent Syndesmotic Injuries: Functional Outcomes and Maintenance of Reduction.

BACKGROUND: Fixation of the tibiofibular syndesmosis is often performed with a trans-syndesmotic screw (SS) or suture-button (SB). SB fixation has been shown to have lower rates of postoperative syndesmotic malreduction, late diastasis, and implant removal, though some studies have found complications related to infection and implant subsidence. The purpose of this study was to compare maintenance of reduction, complications, implant removal and functional outcomes of SB versus SS fixation in adolescents. METHODS: A retrospective chart review identified patients who underwent syndesmotic fixation from 2010 to 2019 at a single institution. Loss of syndesmotic reduction (diastasis) was defined as either a >2 mm increase in tibiofibular clear space or >2 mm decrease in tibiofibular overlap, and corresponding incongruence of the ankle mortise (medial clear space 1 millimeter greater than superior clear space). Functional outcomes were collected at a minimum of 1 year postsurgery using the Foot and Ankle Ability Measure (FAAM). RESULTS: Seventy-seven adolescents (45 SS, 32 SB) were included (mean age: 16±1.5 y). Forty-five patients had Weber C fibula fractures, 27 Weber B fractures, and 5 had isolated syndesmotic injuries or small posterior malleolus fractures. Fifty-one patients (66%) had functional outcomes available. There was no significant difference in mean FAAM Sports score between the 2 groups (SB=94.8%, SS=89.8%) at mean follow-up of 4.0±2.1 years. Syndesmotic implant removal occurred in 36/45 patients (80%) in the SS group compared with 4/32 patients (13%) in the SB group. There was 1 case of syndesmotic malreduction requiring revision surgery in the SS group, and no cases of postoperative malreduction or diastasis in the SB group. Nine patients in the SB group and 8 in the SS group weighed over 100 kilograms, with no cases of diastasis in these larger patients. There were 4 superficial infections and 1 deep infection in the screw group, with 1 superficial infection in the SB group. CONCLUSIONS: While both SB and screw fixation maintained syndesmotic reduction, SB fixation led to lower rates of implant removal surgery. SB fixation was equally effective at preventing recurrent diastasis in adolescents weighing over 100 kilograms, and functional outcomes were at least equivalent to screw-fixation at mean follow-up of 4.0 years. LEVEL OF EVIDENCE: Level III.