[Intraosseus synovial cysts of the lunate bone: diagnostic problems].

Intraosseous ganglia is one of the most frequent lytic defect at the wrist. Its location in the lunate may be discovered by chance on an X-ray performed for another reason, or because of wrist pain and very rarely for a lunate fracture. A.P., lateral and oblique X-rays are mandatory. Bone scan, CT scan and MRI may be of help. Differential diagnosis may exist with an ulnar abutment syndrome with a lunate defect and with all the lytic bone tumours, a systemic disease or multiple defects as in overuse syndromes. In some cases, there is a condensation around the defect and a Kienböck's disease may be suspected. Thirty-seven patients have been operated on between 1978 and 2001, of which 70% were females. Average age was 34 years (16-58). Clinical presentation was always wrist pain. In seven cases, another carpal localization was present. Surgical treatment consisted in bone curettage and cancellous bone grafting. In four cases, a ganglia emerging from the scapholunate space in soft tissues was combined. Pain disappeared after the procedure. A few patients had a 20-30 degrees wrist flexion decrease but without functional impairment. Several theories have tried to explain the onset of these intraosseous ganglia. In conclusion, these lesions are another cause of wrist pain. One has to be sure that this is this lesion which is the real cause of wrist pain. A systematic X-ray has to be performed for painful soft tissue wrist ganglia.