Risk factors for total hip arthroplasty dislocations

Purpose: to identify risk factors of dislocation after total hip arthroplasties and to suggest a model to determine the probability of occurrence of this complication in every patient. Material and methods: since 2000 till 2010 2569 primary and 319 total hip revisions were performed in 2409 patients. The age of patients varied from 15 to 92, average - 58,5. Women were 1582 (65,68%). All procedures were made through the posterior approach (Kocher-Langenbeck). Results: there were 136 dislocations. The authors analyzed three groups of risk factors: 1) related with patient; 2) depending on surgeon; 3) associated with implant design. Most important risk factors were found by the method of logistic regression: age, gender, diagnose, surgeon, cup-to-head ratio. The authors suggested the predictive model of probable dislocation.