Tarsometatarsal bone remodelling after subtalar arthroereisis

Abstract

Purpose: Subtalar arthroereisis has been described for the treatment of flexible juvenile flatfoot. However, the mechanism responsible for deformity correction has not yet been investigated adequately. The aim of this study was to document the effect of subtalar arthroereisis on the tarsometatarsal bone morphology.

Methods: We retrospectively reviewed the clinical and radiological data of 26 patients (45 feet) with juvenile flexible flatfoot deformity treated by subtalar arthroereisis at our department between 2000 and 2018. Radiological evaluation included angular measurements of tarsometatarsal bone morphology as well as hindfoot and midfoot alignment. Mean radiographic follow-up was 19.4 months (sd 8.8; 12 to 41).

Results: A significant change of angular measurements of tarsometatarsal bone morphology was found after subtalar arthroereisis (p < 0.001). While there was an increase of the distal medial cuneiform angle (DMCA) and the medial cuneo-first metatarsal angle on the anteroposterior view, a decrease of the naviculo-medial cuneiform angle and the medial cuneo-first metatarsal angle was seen on the lateral view. Furthermore, we found significant improvements of all hindfoot and midfoot alignment parameters except the lateral tibio-calcaneal angle and the calcaneal pitch angle (p < 0.001).

Conclusion: Our data support the theory of tarsometatarsal bone remodelling, which may contribute to the effect of subtalar arthroereisis for the treatment of flexible juvenile flatfoot.

Level of evidence: IV.

Keywords: bone remodelling; flatfoot; radiological outcome; subtalar arthroereisis.

Fig. 1.

Flow diagram.

Fig. 2.

Anteroposterior radiological measurements: measurement of the distal medial cuneiform angle, talometatarsal I angle and talocalcaneal angle (left foot) and the medial cuneo-first metatarsal angle, talometatarsal II angle and talonavicular (coverage) angle (right foot). Further explanations for the determination of each angle are given in the material and methods section.

Fig. 3.

Lateral radiological measurements: measurement of the talar inclination angle, medial cuneo-first metatarsal angle, naviculo-medial cuneiform angle and Costa-Bartani angle (right foot) and the calcaneal pitch angle, talocalcaneal angle, talometatarsal I angle and medial arch sag angle (left foot). Further explanations for the determination of each angle are given in the material and methods section.