[Treatment of late onset Perthes disease with hip arthroscopy and arthrodiastasis with an external fixator. Case report].

BACKGROUND: The prognosis of late onset Perthes cases is usually poor and the proposed treatments vary based on the surgeon's preferences and experience, as well as on the available resources. Most of them are salvage procedures with a short follow-up and non-standardized application criteria.

METHODS: Hip arthroscopy and arthrodiastasis with external fixator are indicated for certain situations in Perthes disease. Based on the results obtained with each of these techniques separately, both of them were used to treat a case of Perthes disease involving a poor prognosis.

RESULTS: Results two years after surgery are good.

CONCLUSIONS: The use of both techniques together may produce a good result in these patients.