Distraction subtalar joint fusion using a custom 3D-printed implant

A patient-specific custom 3D–printed porous titanium implant for subtalar joint fusion to restore height, length, and alignment of the hindfoot.

Calcaneus malunion/nonunion

Subtalar fusion malunion.

The subtalar joint is comprised of the talocalcaneal joint and the talocalcaneonavicular joints.

The subtalar joint allows for inversion and eversion of the hindfoot but also has a rotational component, allowing the talar head to internally rotate and drop down during eversion.

Calcaneal malunion after a calcaneus fracture typically treated nonoperatively can lead to loss of height, length, varus malposition, widening of the heel, and joint incongruity.

Posterior facet and articular surface malreduction can lead to subtalar arthritis.

Lateral wall blowout leads to increased heel width.

Loss of talar declination due to decreased calcaneal height leads to anterior ankle impingement.

Varus malposition of the calcaneus leads to lateral column overload.

Calcaneal malunion after calcaneus open reduction and internal fixation (ORIF) can cause similar issues as nonoperative treatment of calcaneus fractures. Although calcaneus fractures can be very challenging cases, not restoring appropriate heel alignment (out of varus) and calcaneal height and width, and restoring the articular surface can result in similar clinical findings as above.

Peroneal dislocation is also commonly missed after calcaneus fractures.