Partial algodystrophy of the knee. An anatomico-radiological study of one case.

A 62-year-old man presented with intense pain in the right knee experienced immediately after slipping. The radiograph taken during the following weeks showed the development of a localized radiotranslucence of the lateral femoral condyle. Bone biopsy excluded an infectious process or tumor and revealed the histological characteristics of Sudeck's bone dystrophy. The clinical, radiological and histological data considered together were consistent with a diagnosis of "partial algodystrophy", a term considered preferable to "transient osteoporosis". The diagnosis was confirmed on clinical and radiological followup.