Introduction

Historically, surgeons have focused on isolated simple coalition resection in symptomatic tarsal coalition with concomitant rigid flat foot. However, a review of literature suggests that coalitions with severe preoperative planovalgus malposition treated with resection alone are associated with continued disability and deformity. We believe that concomittant severe flatfoot should be considered as much as a pathological component and pain generator as the coalition itself. Our primary hypothesis is that simple resection of middle facet tarsal coalitions and simultaneous flat foot reconstruction can improve clinical outcomes.

Painful peroneal spastic flatfeet without coalition or other known etiologies in adolescence, remains a difficult condition to treat. We present eight such cases with radiological and surgical evidence of bony abnormalities in the lateral subtalar region just anterior to the posterior facet.

All patients had presented as tertiary referrals with recalcitrant pain and had undergone a trial of orthotics and physiotherapy. Diagnostic workup included a clinical and radiographic evaluation. Clinical examination consisted of gait examination, foot alignment, range of motion, torsional profile of the lower limbs and marking of symptomatic foci. All patients had standing weightbearing anteroposterior and lateral projections of the foot and ankle, CT and/or MRI scans of the foot. Coalitions and other known intra-articular pathologies like subtalar arthritis were ruled out. All patients had bilateral flatfeet but unilateral peroneal spasm.

All patients had an accessory anterolateral talar facet (ATF) which was arising as an anterior and distal extension of the lateral process of the talus. This caused lateral impingement between the facet and the calcaneum, confirmed by bone edema around the sinus tarsi and marked at the apex of the angle of Gissane on MRI scans. All patients had stiff subtalar joints with very limited movement under anaesthesia, indicating peroneal muscle contracture. Patients were treated with a combination of facet excision, fractional peroneal and gastrosoleus lengthening and calcaneal lengthening to correct the flatfoot and prevent lateral impingement.

We describe the medium-term results of a prospective study of 200 total ankle replacements at a single-centre using the Scandinavian Total Ankle Replacement. A total of 24 ankles (12%) have been revised, 20 by fusion and four by further replacement and 27 patients (33 ankles) have died. All the surviving patients were seen at a minimum of five years after operation. The five-year survival was 93.3% (95% confidence interval (CI) 89.8 to 96.8) and the ten-year survival 80.3% (95% CI 71.0 to 89.6).

Anterior subluxation of the talus, often seen on the lateral radiograph in osteoarthritic ankles, was corrected and, in most instances, the anatomical alignment was restored by total ankle replacement. The orientation of the tibial component, as seen on the lateral radiograph, also affects the position of the talus and if not correct can hold the talus in an abnormal anterior position. Subtalar arthritis may continue to progress after total ankle replacement. Our results are similar to those published previously.