Objectives The aim of the thesis was to study the different clinical features of OA in different ethnic groups of patients.

Methods One hundred and sixty six Germans and 50 Egyptian patients with OA were studied. Clinical examination, severity index and radiological score (of all body joints) beside a battery of routine blood tests were done for each patient.

Results There was an increase in the number of joints affected and in total joint lesions among Germans. There was also an increase in age at onset, in disease duration and in family history of OA among Germans. None of the Egyptians had hip affection, while 127 Germans had bilateral or unilateral hip joint affection. Severity index of hips correlated with patients age (p < 0.05) and age at onset (p < 0.05) among Germans. While, severity index of knee joint correlated with age (p < 0.05, p < 0.05) and age at onset (p < 0.05, P -c 0.0 5) among both Egyptians and Germans. While 19 Germans had DISH and 19 Germans had CPPD, none of the Egyptians had neither DISH syndrome nor CPPD. Thirteen Germans but none of the Egyptians had knee effusion.

Environmental, habitual and occupational causes, among others, seem to modify the clinical features of OA between ethnic groups of patients.