Augmented Broström is Associated with Improved Functional Outcomes as Measured by PROMIS Scores Compared to Broström Without Augmentation

Research Type: Level 3 - Retrospective cohort study, Case-control study, Meta-analysis of Level 3 studies Introduction/Purpose: It is unknown whether primary Broström with InternalBraceTM augmentation results in improved functional outcomes compared to primary Broström without augmentation for patients with chronic lateral ankle instability. No study to date has compared functional outcomes measured by the validated Patient Reported Outcomes Measurement Information System (PROMIS) computerized adaptive tests (CATs) of physical function (PF) and pain interference (PI) between augmented Broström and Broström without augmentation. Our study therefore aims to determine whether augmented Broström is associated with improved PROMIS scores compared to Broström without augmentation. We hypothesize that augmented Broström will have higher PF and lower PI compared to Broström. To our knowledge, this investigation is the largest retrospective study comparing PROMIS scores between patients undergoing augmented Broström and Broström without augmentation procedures. Methods: 574 patients who underwent lateral ankle ligament reconstruction at a single institution between January 2013-January 2024 were retrospectively reviewed. Two investigators independently evaluated all records. Revisions, Evans procedures, allografts, nonanatomic reconstructions, flexor digitorum longus transfers, pes planus deformities, concomitant tibiotalar arthrodesis, associated ankle arthroplasties, and concomitant fractures or nonunions were excluded. 392 remaining patients were contacted to complete PROMIS CATs. 127/392 consented to complete PROMIS CATs. Patients were classified based on ankle instability etiology: active individual (chronic ankle instability without anatomic deformity), osteochondral defect, or deformity (hindfoot/ankle varus or valgus deformities or equinus contractures). Bivariate comparisons of patient characteristics were performed across Broström techniques. T-tests and Kruskal-Wallis tests were used to assess associations with PROMIS. Linear regression was used to assess the strength of associations. The adjusted models were selected according to adjusted R-squared and AIC, and included age, sex, BMI, and etiology of instability. Results: 80/127 (63%) augmented Broström and 47/127 (37%) Broström without augmentation were included for final analysis. PROMIS PF was significantly higher in the augmented group compared to the non-augmented group (51.7±8.1 vs. 48.5±8.9, P=.04). PI was lower in augmented vs. non-augmented, though this value did not reach statistical significance (48.6±8.2 vs. 51.3±9.9, P=.09). In adjusted regression models, augmented had an estimated PF 3.91-points higher than non-augmented (P=.01) and an estimated PI 3.50-points lower than non-augmented (P=.02). Deformity and higher BMI were associated with worse PF (P <.05), while deformity, higher BMI, and female sex were associated with worse PI (P <.05). Conclusion: Augmented Broström significantly improves PF and PI compared to non-augmented Broström to a degree that reaches the minimal clinically important difference for PROMIS reported in prior literature. Augmented Broström with InternalBrace therefore may be the preferred surgical option over Broström without augmentation to maximize PF and minimize pain levels in patients with chronic lateral ankle instability. Broström repair with InternalBrace augmentation exceeds the native anterior talofibular ligament (ATFL) strength, does not violate normal tissue, and helps protect the ligament repair while it matures, allowing early mobility during recovery and a quicker return to activity.