 The aim of this prospective randomized clinical trial is the comparison of two surgical treatment options for talar avascular necrosis analogical to Ficat and Arlet stage II and III. The randomized study design allows direct comparability of the outcome after either core decompression and nonvascularized osseous autografting from the iliac crest or core decompression and osseous autografting with a free microvascular medial femoral condyle. 