The Effect of Acetabular Component Inclination on Early Dislocation Rate of Hip Arthroplasty

Dislocation of total hip arthroplasty may happen for different reasons. Abnormal acetabular orientation is a common reason for such occurance. We would like to report the effect of acetabular inclination on incidence of dislocation.

In a cross-sectional study all cases of total hip arthroplasty performed in a 2-yaer interval in one educational hospital in Tehran were followed and assessed for possible dislocation in a 18.1 months (3-25 months) of follow-up. The inclination angles of acetabular components were measured and the relationship of dislocation with gender age and this angle was evaluated.

132 cases entered the study. 4 patients (3%) encountered dislocation; and all 4 had inclination angles of over 50 degrees. Gerder did not seem to play an important role. Older age however was probably contributing to risk of dislocation.

Inclination angle of over 50 degree in acetabular component position is one of the factors making it more likely for the hip arthroplasty to dislocate.