OBJECTIVETo investigate the clinical manifestations and risk factors of the patients from developmental dysplasia of the hip(DDH) family.

METHODSDetailed epidemiology investigation, physical examination, functional movement assessment, lab test and X-ray examination were applied to the whole members of a DDH family.

RESULTSIn the family with 9 generations and 218 persons, the incidence of DDH was 31.03% in 145 survivors. Patients mainly manifested bilateral knee and hip joint pain, flexion contracture of hip, limitation in internal and external rotation of hip; a few had arthritic functional disorder, deformation, and limp. The radiography illustrated shallow acetabulum with increased inclination, which encompassed the femoral head badly. Deformation of the femoral head, narrow joint space and osteophyte were also found by X-ray examination. The main risk factors of DDH were genetic factors, gender, birth season etc. The son or daughter with one or two DDH parents had a higher risk for developing DDH than those with no DDH parents. Furthermore, first-degree relatives of the DDH patients also had a greater chance to develop DDH than second-degree relatives and third-degree relatives. The incidence among females was higher than males, and the family member who was given birth in winter had a highest risk for developing DDH. However, there was no difference between incidence of DDH in children and youths and in adults; the incidence of DDH in the immigrants with no blood relationship also did not differ from the incidence of DDH in the family member.

CONCLUSIONThe genetic factors play an important role in the development of DDH, so do the environmental factors.