We concluded that the combination of grey scale US and PDS could be used as a sensitive and reliable non-invasive and widely available method complementary to standard clinical assessment & laboratory measures for evaluating many rheumatic diseases in daily practice.We found no specific ultrasonic feature specific for HCV related knee arthritis; however knee effusion is a predominant feature & the hypertrophied synovium not frequently found. No degenerative or destructive lesions was found to be related to the disease itself, however this should be confirmed by histopathological assessment.The detection of synovitis & bone erosions at articular joint margins is an essential diagnostic criterion in RA, and it is routinely used as a valuable measure of diagnosis, prognosis and disease severity.Finally we concluded that there is a role of inflammation in painful KOA, other causes of pain may be contributed to knee effusion, menscal extrusion, Baker's cyst & bursitis are frequent causes of pain in symptomatic KOA.