Increased level of apolipoprotein B/apolipoprotein A1 ratio as a potential risk for osteonecrosis.

OBJECTIVE This study was performed to investigate whether a high ratio of apolipoprotein B to apolipoprotein A1 (apo B/apo A1 ratio) is significantly associated with the risk of developing non-traumatic osteonecrosis of the femoral head (ON). METHODS Fifty consecutive non-traumatic ON cases were compared with 50 age and sex matched controls, using both univariate and stepwise discriminant analyses, regarding the factors of corticosteroid, alcohol, cigarettes, cholesterol, triglyceride, and apo B/apo A1 ratio. To eliminate the possibility that ON or osteoarthritic change itself can increase the apo B/apo A1 ratio, a further 32 consecutive cases comprising nine traumatic ON and 23 osteoarthritis (OA) patients were analysed using Scheffe's test. RESULTS There was a significant association between a high apo B/apo A1 ratio and the development of non-traumatic ON with both univariate (p=0.0001) and stepwise discriminant analyses (partial r(2)=0.1239, p=0.0004). The apo B/apo A1 ratio in the non-traumatic ON group was significantly higher than that in the traumatic ON (p<0.01), control (p<0.001), or the OA groups (p<0.001). CONCLUSION A high apo B/apo A1 ratio is significantly associated with the risk of developing ON. This ratio may be useful for assessing the potential risk of developing osteonecrosis.