Innovative Soft Tissue Reconstruction of the Spring–Deltoid Complex in Progressive Collapsing Foot Deformity (Flatfoot): Early Clinical Results

Progressive Collapsing Foot Deformity (PCFD), previously termed Adult Acquired Flatfoot Deformity (AAFD), is a progressive condition characterized by failure of medial soft tissue structures leading to painful biomechanical dysfunction. Traditional reconstructions often rely on nonanatomic osteotomies, such as lateral column lengthening, which carry notable risks. This study evaluates a novel soft tissue reconstruction of the spring-deltoid ligament complex combined with medial column osteotomies for stage II PCFD. Methods: A retrospective case series was performed on 9 feet in 8 patients (mean age 44.7 years) treated between September 2021 and December 2024. The surgical technique included spring ligament InternalBrace™ augmentation with Flexor Digitorum Longus (FDL) transfer, Cotton osteotomy with titanium wedge and minimally invasive Medial Calcaneal Osteotomy (MICO). Pre- and postoperative radiographs were analyzed for Meary’s angle, talocalcaneal angle, calcaneal inclination angle, calcaneocuboid angle and intermetatarsal angle. Functional outcomes were assessed using FAOS and AOFAS hindfoot scores. Paired t-tests determined statistical significance (p < 0.05). Results: All radiographic parameters demonstrated significant improvement: Meary’s angle (14.56° → 2.11°), talocalcaneal angle (28.11° → 18.44°), calcaneal inclination (11.67° → 15.89°), calcaneocuboid angle (21.11° → 12.11°) and intermetatarsal angle (11.11° → 6.67°) (all p < 0.05). Functional outcomes also improved, with mean FAOS of 79.1 ± 10.5 and mean AOFAS of 84.3 ± 3.8 at an average of 21 month follow-up. No patients required adjunctive lateral column lengthening and no construct failures or major complications were observed. Conclusion: Spring-deltoid ligament reconstruction with InternalBrace™ augmentation, combined with MICO and Cotton osteotomy, achieved significant radiographic and functional correction in stage II PCFD without the need for nonanatomic lateral column lengthening. This technique may provide a safer, anatomic alternative to traditional reconstructions, offering reliable restoration of medial column stability and improved patient-reported outcomes. Level of Evidence: IV (Retrospective case series).