Minimally invasive deltoid ligament reconstruction for stage IV flatfoot deformity

Stage IV is the most advanced form of acquired adult flatfoot deformity (AAFD). It is present when valgus tibiotalar angulation occurs with foot deformities associated with AAFD. Tibiotalocalcaneal or pantalar fusion has been the gold standard for treatment of Stage IV AAFD. However, in some of these patients the tibiotalar deformity is correctable. We sought to determine whether minimally invasive deltoid ligament reconstruction in conjunction with triple arthrodesis (MIDLR/Triple) allows tibiotalar joint sparing surgical therapy in Stage IV-A AAFD patients.

Patients diagnosed with Stage IV-A AAFD were given the option of undergoing ankle joint sparing surgery with the MIDLR/Triple technique. Those that chose this option were followed longitudinally. Eight patients underwent the ankle joint sparing procedure. Average followup was 36 months. Radiographic and functional outcome measures were obtained. Success was defined as maintenance of 3 degrees or less of valgus tibiotalar angulation and greater than 2 mm of lateral joint space remaining at final followup.

At final followup, five were judged to have a successful outcome. In those, tibiotalar valgus angulation was reduced from 6.4±2.9 degrees to 2.0±2.0 degrees, lateral ankle joint space was maintained at preoperative levels and SF-12 functional scores were equal to age matched normative scores. The only parameter found to be predictive of successful outcome was the magnitude of preoperative tibiotalar tilt.

MIDLR/triple is a new treatment option that requires significant care in patient selection and surgical execution. It is a choice that allows for preservation of ankle motion in patients diagnosed with Stage IV-A AAFD who have less than 10 degrees of valgus tibiotalar tilt on preoperative standing ankle radiographs.