OBJECTIVETo determine whether bone density is related to osteoarthritis and to compare osteoarthritis with osteoporotic fracture of the femoral neck.

METHODSAll 165 femoral heads removed at joint replacement surgery were divided into 4 groups according to radiographic features of hip (osteophytes, subchondral sclerosis, cysts and femoral head deformity). The individual femoral head was divided into 5 zones histologically. Sections were studied histomorphologically, and quantitation was performed using the computer-assisted system to determine the bone density of the femoral head.

RESULTSThe values of bone density in weight-bearing, super lateral non weight-bearing (SL) and inferior medial non weight-bearing (IM) areas after femoral neck fracture in patients with osteoarthritis were lower than normal. The values of bone density in weight bearing area were increased in patients with osteoarthritis in all four groups but lower than normal in one group (I), and higher than normal in other 2 groups (III, IV). The values of bone density in SL and IM areas except IM area in group IV were lower than normal (P > 0.05). The values of bone density in the central area in the 4 groups were relatively consistent and normal. The density of Haversian canals was increased in the 4 groups indicating osteoporosis of the femoral head. The average age of patients with femoral neck fracture associated with OA (group I) was significantly higher than that of group II, III, IV (P < 0.05).

CONCLUSIONSBone density is different in the femoral head and neck. Dividing the weight bearing joint into distinct zones is a method for laboratory and clinical study. Femoral neck fracture associated with OA was caused by osteoporosis which is related to the age of the patient. The data of this study can be regarded as a potential indicator of implant/host bone relations with morphological, morphometric implications.