2.1

127 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, allografts, nonanatomic reconstructions, flexor digitorum longus transfers, progressive collapsing foot deformities, concomitant hindfoot arthrodesis, associated ankle arthroplasties, and concomitant fractures were excluded. 37 patients with structural ankle deformity (varus deformity, n = 37) were identified. Cavovarus deformity was defined radiographically by an increased talo-first metatarsal angle, or Meary’s angle, (>4° convex upward), elevated calcaneal pitch (>30°), increased first metatarsal-calcaneal angle, or Hibb’s angle, (>45°), and a decreased talocalcaneal angle (<20°). These 37 patients were contacted by email to complete surveys via REDCap containing PROMIS CATs and CAIT, as well as additional questions querying self-reported ability to increase activity postoperatively compared to preoperative baseline . After an initial email, if patients did not complete surveys or declined consent, subsequent email and phone calls were attempted for a total of five attempts. All surgeries were performed by foot and ankle fellowship-trained orthopaedic surgeons (n = 4). Surgeon preference determined the choice of traditional Broström versus augmented. Due to evidence suggesting increased stability with mechanical load in augmentation ^,,, , surgeons at our institution often performed augmented procedures for patients with deformities, especially considering many of these patients had poor tissue quality. A greater proportion of patients had Broström with augmentation after 2017 because the authors’ institution began performing more augmented than non-augmented due to evidence suggesting augmentation results in improved stability and response to mechanical load ^, . Augmentation was performed using Internal Brace suture tape (Arthrex, Naples, FL). While a current gold standard has not yet been established, this study seeks to understand which patients and underlying pathologies may benefit most from augmentation.

Many patients in this cohort underwent concomitant procedures at the time of lateral ankle ligament reconstruction. These include correction of bony deformities (i.e., calcaneal osteotomy) and additional soft tissue procedures (i.e. ligamentous reconstruction, synovectomy, tendon transfer, tendon lengthening, etc.). Additional procedures are outlined in Table 1 .

2.2

Primary outcomes included PROMIS PF and PROMIS PI. Both measures correspond to age-matched norms for the US general population mean score of 50 ^,, . Higher PF designates higher physical function, while higher PI indicates more pain interfering with activity. The minimally clinically important difference (MCID) reported in the literature for PROMIS is a difference of 3–30 for PF and 3–25 for PI . Secondary outcomes included postoperative CAIT scores. Higher scores on CAIT indicate greater ankle stability. The MCID reported in the literature for CAIT is a difference of ≥ 3 . Follow-up duration was defined as time from surgery to time to survey completion.

2.3

T-tests and Kruskal-Wallis tests were used to assess associations between CLAI etiology and PROMIS, as well as between CLAI etiology and CAIT. This study reached 80 % power to detect minimum effect size of 0.52 (Cohen’s d), corresponding to differences of 4.37 for PF and 4.60 for PI, and 80 % power to detect an effect size of 1.15, corresponding to an actual difference in CAIT of 9.24. Therefore, the study was underpowered to detect differences in CAIT.