Novel technique for deltoid spring complex reconstruction in progressive collapsing foot disorder

Introduction

Adult Acquired Flatfoot Deformity (AAFD) is a progressive condition characterized by the collapse of the medial foot arch, often caused by posterior tibial tendon dysfunction or deltoid spring ligament incompetency. Flexible type 2 AAFD results in peritalar subluxation and instability. The deltoid and spring ligament complex plays a critical role in foot stability. Current surgical treatments include ligament reconstructions, tendon transfers, and osteotomies, but comprehensive approaches for advanced cases are limited. This study compares two novel techniques—Quadrangular and Triangular repairs—using fiber tape or wire for reconstruction of the deltoid spring complex, combined with medial displacement calcaneal osteotomy (MCDO) for Stage II AAFD.

Materials and methods

Forty patients (mean age 44.6 years) with Stage II AAFD, unresponsive to conservative treatment, were enrolled between December 2023 and 2024. Both surgical techniques, combined with MCDO (excluding lateral column lengthening), were performed. Clinical and radiological assessments were made preoperatively, at 3 months, and at 12 months. The AOFAS Ankle-Hindfoot scale assessed functional outcomes, while radiological parameters such as Meary's angle, talonavicular coverage, and tibial-calcaneal angle were evaluated.

Results

At 3 and 12 months post-surgery, both techniques showed significant improvements in clinical (AOFAS) and radiological outcomes, including Meary’s angle and hindfoot alignment (p < 0.01). Triangular repair demonstrated slightly better functional outcomes, but both techniques effectively restored foot biomechanics and alignment. Complications included wound dehiscence, metal irritation, and persistent subtalar pain, which resolved with conservative treatment.

Conclusion

Quadrangular and Triangular repair techniques, augmented with fiber tape or wire and combined with MCDO, are effective for Stage II AAFD. Both methods improve clinical and radiological outcomes, with Quadrangular repair showing a slight advantage in functional recovery in severe deformity. These findings suggest that a personalized approach based on talonavicular coverage optimizes AAFD management.