Intermediate to Long-Term Clinical and Radiographic Results of Deltoid Ligament Reconstruction with Tendon Graft

CATEGORY: Ankle, Hindfoot, Flatfoot INTRODUCTION/PURPOSE: Adult acquired flatfoot deformity (AAFD) is a complex deformity characterized by hindfoot valgus, medial longitudinal arch collapse, midfoot abduction, and forefoot supination. In its most advanced stages (stage IV), the deltoid ligament is compromised, which leads to valgus talar tilt at the tibiotalar joint. This talar tilt puts patients at high risk of developing ankle arthritis necessitating ankle arthrodesis or arthroplasty. Tendon graft reconstruction of the deltoid ligament has previously demonstrated good clinical and radiographic outcomes at short to intermediate-term follow-up but controversy over efficacy of the procedure remains. The goal of the current study was to present the intermediate to long-term clinical and radiographic outcomes of the largest series to date of patients undergoing this procedure. METHODS: Data from a prospectively collected Foot and Ankle Registry was reviewed. All consecutive patients undergoing deltoid ligament reconstruction with tendon allograft or autograft as part of their flatfoot surgery by the senior author prior to 1/1/2015 were eligible for inclusion. Patients with radiographic follow-up of <3 years were asked to return for follow-up under an IRB- approved study protocol. Patients missing preoperative radiographs or unable to complete follow-up were excluded from radiographic analysis. Measurements of talar tilt were performed on AP ankle x-rays by two observers (Figure 1). Reliability analysis was performed using intraclass correlation. Preoperative Foot and Ankle Outcome Scores (FAOS) were obtained from the registry. Patients were contacted to complete postoperative FAOS and PROMIS surveys. Paired t-tests were used to evaluate changes in talar tilt and clinical outcomes. P-values of less than 0.05 were considered significant. RESULTS: 35 feet/34 patients were eligible. Two feet/patients failed treatment (one ankle fusion, one deep infection and amputation). Three patients were deceased, two unable to follow-up due to unrelated medical problems, one missing preoperative imaging, and five unwilling to return for long-term follow-up. None of these patients failed treatment at last follow-up. 21 feet/20 patients (7/7 female) underwent radiographic analysis. Mean age at surgery was 58.4 (43.8-80.9) years. Interobserver agreement assessing change in talar tilt was excellent (ICC=.892). At mean radiographic follow-up of 10.3 (4.1-18.3) years, talar tilt improved significantly from an average of 9.71 +/- 6.22 degrees preoperatively to 3.63 +/- 3.27 degrees valgus postoperatively (p<.001). All FAOS subscores improved significantly pre to postoperatively. Postoperative PROMIS scores were comparable to or better than population means. CONCLUSION: Our findings demonstrate that deltoid ligament reconstruction with tendon graft enables radiographic correction, though not always complete, in patients with stage IV AAFD over the medium to long-term. Although limited by the sample size, our study demonstrates overall good clinical outcomes with few treatment failures. Though accessory procedures performed routinely at the time of flatfoot reconstruction present possible confounding variables, untreated ankle valgus likely leads to worsening deformity and ankle arthritis. Although the correction is not necessarily full, surgical reconstruction of the ligament may preclude patients from requiring joint sacrificing procedures such as ankle fusion or replacement over the long-term.