Introduction:

The dislocation of the total hip replacement can affect the results of the implant, the quality of life of the patient, and the cost of the process. Its etiology is multifactorial.

Objectives:

To identify possible risk factors related to the appearance of dislocation in total hip replacement in a series of cases.

Methods:

In a series of 2732 total hip prostheses, in which there were 92 dislocations (3.4%), factors related to the patient, the implant, and the surgical technique used at La Paz-IDIPaz Hospital in Madrid were compared, from 2000 to 2016. Regression analysis was used for the significance of these factors.

Results:

Out of 92 dislocations, 62 were treated conservatively (67.4%) and 30 patients required revision surgery (32.6%). The multivariate study showed statistical significance in the following risk factors: state of the lumbar spine (p <0.001), and poor reconstruction of the center of rotation of the hip (p = 0.035), and domes positioned outside Lewinnek windows (p <0.001) and the abductor mechanism (p <0.001) in relation to the surgical technique. There were no significant factors in relation to the type of implant, diameter of the femoral head or friction torque.

Conclusions:

Lumbar pathology increases the risk of dislocation in total hip replacement. Proper hip reconstruction, including the position of the dome and the center of rotation of the hip, as well as the abductor mechanism, would help to improve the rate of instability.

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