ABSTRACT
Objective A group of patients who had undergone total hip arthroplasty were followed up radiologically to explore the effects of abduction angle, the anteversion angle and the height of the femoral head center on dislocation, because these measurements could be used as a basis to evaluate current practice and to seek improvements. Methods A series of 326 hip joints (318 patients) were followed up routinely. The average follow up period was 2.7 years. 10 was found to have dislocation. The abduction angle, the anteversion angle and the height of the femoral head center were measured. The results were statistically analyzed, with a P value less than 0.05 indicating significant difference. Results The abduction angle of 55?or larger was found to be associated with greater risk of dislocation, compared with the abduction angle of less than 55?. Meanwhile, cups with the femoral head center superior placement greater than 30 mm resulted in more dislocation, compared with those less than 30 mm. As an independent variable, the anteversion angle had no significant association with dislocation. Conclusions Based on the results of the current study, the abduction angle and the height of the femoral head center should be considered as prerequisites for maintaining hip stability and decreasing the risk of dislocation. We believe that hips with the abduction angle of less than 55?and the height of the femoral head center less than 30 mm can decrease the risk of dislocation.