3D-printed custom hemi-talus replacement

Resection of damaged cartilage and subchondral bone in the talus which is then replaced with a metallic, patient-specific, 3D-printed implant without the need for malleolar osteotomy.

Chronic, medium-to-large osteochondral defects (OCDs) of the talar dome which are often uncontained (i.e., involving the talar shoulder) and have mixed cystic and sclerotic subchondral bone.

Prior failed arthroscopic OCD repair which may include debridement, microfracture, or morselized cartilage allografting.

Prior failed open treatment of the OCD which may include structural allograft resurfacing or osteochondral transfer.

60% of the talus is covered by articular (hyaline) cartilage which contains no nervous, vascular, or lymphatic vessels.

The exact etiology of talar OCDs has been theorized to be direct trauma, microtrauma secondary to instability or deformity, and spontaneous focal avascular necrosis (AVN).

With time, OCDs may progress in size, develop cystic bone and sclerosis, subchondral collapse, and higher, asymmetric contact stresses.

There is concern for the development of localized arthritis but, in general, OCDs do not progress to diffuse arthritis.

Classically, acute lateral OCDs tend to be more shallow and anteriorly located, whereas acute medial lesions are cup-shaped, deeper, and located in the central to posterior aspects of the talar dome. In our experience, chronic lesions, especially if prior surgical intervention, are more irregularly shaped, have a variable/nonuniform depth, and a degree of local AVN.

In the authors’ experience, patients complain of anterior or “deep” aching ankle pain with or without clicking, popping, or catching of the ankle, which is worse with activity.

If trauma is reported, which often is not, it most often involves remote or recurrent ankle sprain. Less often the patient will report a previous malleolar fracture.

Patients may limp or complain of inability to perform athletic or recreational activities.

Stiffness is a common symptom, especially with chronic OCDs.

Stability testing may elicit guarding, pain, or frank laxity.

Immobilization often improves but does not eliminate symptoms.

Patients may report that prior corticosteroid injection provided temporary relief.