ARTHRODESIS OF THE SUBTALAR AND TALONAVICULAR JOINTS THROUGH A MEDIAL SURGICAL APPROACH: A SERIES OF 19 CASES

Abstract

Introduction: The double-hindfoot arthrodesis (subtalar and midtarsal joints) is traditionally performed through a lateral surgical approach associated or not with a medial approach. The main goal of this procedure is to correct severe deformities of the hindfoot in varus or in valgus. In this study we report a series of 19 double-hin-foot arthrodeses through a single medial approach.

Methods and Materials: 19 double arthrodeses (subtalar and talonavicular joint) were performed on 16 patients, 8 males and 8 females with a mean age at surgery of 58.3 years (range 27–72). The indications were: 12 pes planovalgus and 7 cavus foot. 9 deformities were fixed (3 in valgus and 6 in varus).

The chosen surgical technique was always identical using a medial approach and performed by a single dedicated orthopaedic foot and ankle surgeon (JLB), followed by an osteotomy of the insertion of the Tibialis posterior muscle to the Navicular bone, distraction and avivement of the articular surface done without bone resection, reduction of the talus on the calcaneus, fixation of the talonavicular joint with titanium staples (Pareos®) and of the subtalar joint with two 6.5 mm canulated cancellous screws (Unima®). On five occasions (in 3 pes planovalgus and in 2 cavus foot) arthrodesis of the calcaneocuboid joint was carried out through a mini lateral approach due to painful arthritic lesions.

Results: The average follow up was 16.5 months (range 6–40). Consolidation was always achieved.

In the subgroup with pes planovalgus: the mean Kitaoka score increased from 44 to 75, the axis of the hind-foot decreased from 21° to 11° in valgus, Djian’s angle decreased from 142° to 134.4°, the slope of the calcaneus increased from 17° to 19.4°. Two failures of the associated medial ligament reparation have led to a secondary complementary arthrodesis of the talo-crural joint.

In the subgroup with cavus foot: the mean Kitaoka score increased from 16 to 67. The axis of the hindfoot decreased from 13° in varus to 0.6° in valgus. Djians’s angle increased from 117° to 127.4°, the slope of the calcaneus ranges from 21.3° to 21.5°.

Discussion: The double-hindfoot arthrodesis via a medial approach permits the fusion without developing nonunion (in comparison with 20% non-union of triple arthrodesis reported in the literature).

Double arthrodesis via a medial approach provide a significant correction of the fixed deformities without resorting to bone grafts. Not classically used in cavus foot, it has permitted the correction of the cavo varus deformity without complications of the surgical wound and by extending the approach, a double elevating osteotomy of the metatarsal bases was performed when necessary.