3D-printed solutions for avascular necrosis of the talonavicular joint

Excision of the talus and navicular in total, which is then replaced with a metallic, patient-customized 3D-printed implant.

Avascular necrosis (AVN) of the talus and/or the navicular.

Comminuted fracture of talus and navicular.

Post-traumatic arthritis with poor bone quality and cystic formation.

Osteolysis or bone resorption secondary to an infection.

The talonavicular joint (TNJ) is a ball and socket type of joint that consists of the articulation between the concavity produced by the proximal posterior aspect of the navicular and the convex, ellipsoid surface of the talar head.

The articulation of the TNJ is maintained by various ligaments, including the talonavicular ligament, the bifurcate ligament, and the calcaneonavicular (spring) ligament.

The TNJ composes the transverse tarsal joint and is an essential joint in the medial column, forming a portion of the medial longitudinal arch.

The primary plane of motion for the TNJ is from dorsal lateral to plantar medial. Its primary function is as part of the transverse tarsal joint along with the calcaneocuboid joint, which acts in unison with the subtalar and ankle joint during gait.

Talonavicular motion and function is closely paired with the subtalar joint. Fusion of either joint tremendously affects the other in terms of remaining functional motion.

Vascular supply of the talus and navicular is delicate, with the predominant vascular supply coming from two main suppliers, the dorsalis pedis and the medial branch of the posterior tibial artery. ^,

AVN is characterized by osseous cell death secondary to vascular compromise. AVN can result from a variety of causes, including corticosteroid use, trauma, osteomyelitis, septic arthritis, alcoholism, sickle cell disease, diabetes, and systemic lupus erythematosus (SLE). ^,

Spontaneous osteonecrosis of the navicular and talus (SONNT) is an idiopathic disease that is characterized by symptomatic osteonecrosis of both the navicular and talus simultaneously with associated osteoarthritis of the TNJ. While the cause of SONNT is unknown, possible atraumatic causes are insufficient blood supply and developmental reasons.

Comminuted fractures frequently occur after high-impact trauma and can result in the splintering of bone into multiple fragments as well as the disruption of vascular supply.