[Amyloid osteoarthropathy in dialyzed patients: integrated imaging]

We studied with US both the knees of 32 long-term dialysis patients (mean dialysis age: 69.7 months), 7 of whom exhibited palpable joint swelling. In 29/32 patients, US scans were combined with knee X-ray films, patellar views included. In one case, opaque arthrography was performed too. US demonstrated the presence of fluid collections within both joint space and synovial cavities in 19/32 patients (59%). Their content was transonic or mildly hypoechoic. X-ray films were positive for amyloid bone involvement in 19/29 cases (66%), with evidence of intra-osseous cysts and cortical erosions. There was a good general agreement between the results obtained with the two techniques: therefore, in some cases only one examination was positive. Needle aspiration of synovial fluid was performed in 18/32 patients (56%). The 2 cases of diffusely hypoechoic collections yielded very dense jelly material, that was highly positive for beta-2-microglobulin. US is proposed, combined with conventional X-ray films, as a simple and reliable method for the diagnosis of articular amyloidosis in dialysis patients and for the follow-up of this disease.