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Avascular necrosis of humeral trochlea: A case report of the rare condition.

İntroduction: Avascular necrosis of humeral trochlea is a very rare condition and was described by Hegemann in 1957. We reported two cases of avascular necrosis of humeral trochlea and also performed a literature review of the reported cases. We expect that this case report will assist clinicians to make timely diagnosis when encountering similar clinical scenarios.


MATERIALS AND METHODS
We presented 11-year-old and 14 year-old two cases with avascular necrosis of humeral trochlea. The common etiology was idiopathic because there were no recent trauma history and sports activity. Also there was no history of drug use. We discussed the clinical and radiologic findings of these cases.


RESULTS
These cases were diagnosed as Hegemann's disease with clinical and radiologic outcomes. We found the etiology of both two cases is idiopathic. Both two cases were boys and teenagers. The number of previously reported cases in the literature is limited to 63. In our study there was a lateral crest in one of our two cases and a posteromedial involvement in another. The radiograph of two trochlea of these two cases showed irregularity and granular appearance. In our case, heterogeneous signal changes and irregularities are accompanied by hypointense changes on T1-weighted images. Also hyperintense changes on proton density sequences were detected.


CONCLUSION
Radiological evaluation plays an important role in the diagnosis and evaluation of response to treatment in avascular necrosis of the humeral trochlea. Avascular necrosis should be one of the differential of lesions involving the trochlea. Recognition of avascular necrosis in the trochlea may prevent unnecessary biopsy.