Avascular Necrosis of Humeral Trochlea: A Case Report of the Rare Condition.

Introduction: 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 in making a timely diagnosis when encountering similar clinical scenarios.

Materials And Methods: We presented cases of an 11-year-old and a 14-year-old with avascular necrosis of the 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 radiological findings of these cases.

Results: These cases, two teenage boys, were diagnosed withHegemann's disease with clinical and radiological outcomes. We found that the etiology of both thecases is idiopathic;. The number of previously reported cases in the literature is limited to 64. In our study, there was a lateral crest in one of our two cases and a posteromedial involvement in another. The radiograph of trochleae of these two cases showed irregularity and granular appearance. In our case, heterogeneous signal changed and irregularities were accompanied by hypointensive changes on T1-weighted images. Also, hyperintensive 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 lesions involving the trochlea. Recognition of avascular necrosis in the trochlea may prevent the unnecessary biopsy.