Does Syndesmotic Fixation Technique Impact Complication Rates and Functional Outcomes Measured by PROMIS Scores Following Operative Repair of Ankle Fractures?

Background: It remains unclear whether syndesmotic fixation technique impacts outcomes following ankle fracture surgery. This study investigates which repair technique (transsyndesmotic screws, TightRope, and Internal Brace) results in fewest complications and best functional outcomes measured by Patient Reported Outcome Measurement Information System (PROMIS) computerized adaptive tests (CATs) of physical function (PF) and pain interference (PI). Methods: 782 patients who underwent ankle fracture surgery at a single institution between 2016–2021 were retrospectively reviewed. Two fellowship-trained orthopaedic surgeons independently reviewed all radiographs, determined fixation technique, and assessed complications. Open fractures, pilons, and neuropathies were excluded. 252 had syndesmotic injury identified via intraoperative fluoroscopy. 159/252 who had minimum one-year radiographic follow-up were included for complications analysis. These 159 were sent post-operative PROMIS CATs. 68/159 consented and were included for final analysis of PROMIS. Kruskal-Wallis test compared PROMIS across repair types. Multinomial logistic regression adjusted for propensity scores included as covariates modeled PROMIS by technique. Results: 62/159 had screw, 59/159 TightRope, and 38/159 Internal Brace. Screw complication rate was 12.9% (8/62): 8.1% (5/62) degenerative joint disease (DJD), 6.5% (4/62) syndesmotic malreduction. TightRope complication rate was 1.7% (1/59): 1.7% (1/59) DJD. Internal Brace had no radiographic complications. Mean PF was 50.5 ± 7.9 screw, 53.9 ± 9.7 TightRope, and 52.2 ± 13.1 IB (p = 0.72). Mean PI was 49.6 ± 8.2 screw, 47.9 ± 8.8 TightRope, and 49.2 ± 10.5 IB (p = 0.75). Mean PF was 5.1-points (95%CI: -0.9-11.1) higher for TightRope and 5.2-points (95%CI: -1.3-11.7) greater for Internal Brace vs. screw. Mean PI was 3.2-points less for TightRope (-3.2, 95%CI:-8.5-2.1) and 4.4-points less for Internal Brace (-4.4, 95%CI: -10.1-1.3) vs. screws. Conclusions: Syndesmotic fixation with either TightRope or Internal Brace reduces complications compared to screw. While this study was underpowered to detect differences in PROMIS, improved PROMIS for TightRope and Internal Brace vs. screws suggest that these techniques may result in better functional outcomes compared to screws.