Iatrogenic Avascular Necrosis of the Talus Following Subchondroplasty

CATEGORY: Ankle, Basic Sciences/Biologics INTRODUCTION/PURPOSE: Subchondroplasty® (SCP®) (Zimmer Holdings, Inc, Warsaw, IN) is a relatively new procedure that was developed in 2007 for the treatment of bone-marrow lesions (BMLs). It involves the injection of flowable nanocrystalline calcium phosphate (CaP) synthetic bone substitute into the BML using fluoroscopic-guidance, in order to promote healing and reinforce the effected region. Although a newer technique, SCP has been shown promising results in the knee through several different small case-series. The foot and ankle literature is sparser, with only a few documented case-reports or case-series. As a result, we wanted to report our small case-series of patients who underwent talar SCP and went on to develop avascular necrosis (AVN). METHODS: A retrospective review was conducted of patients who underwent SCP for a talar BML at our facility or were referred to our facility after undergoing SCP at an outside institution. Patients who developed iatrogenic talar AVN postoperatively were included in the study. Patient characteristics, comorbidities, imaging, and need for further surgery was analyzed. RESULTS: Four patients were identified who had previously undergone talar SCP and went on to develop iatrogenic talar AVN. Two patients had their original SCP performed at our facility, whereas the other two patients were referred from outside institutions. All four patients were symptomatic from their AVN. Two patients have undergone revision surgical intervention, while the other two patients are pending surgical intervention. CONCLUSION: This case-series is the first study, to our knowledge, to report iatrogenic talar AVN after undergoing SCP for talar BMLs. Although early studies in the Foot and Ankle literature are promising for use of this technology, these studies have been small and surgeons should be aware of this potential complication.