Abstract
Background
Dislocation is one of the commonest complications of total hip arthroplasty (THA) with incidence of between 0.3 and 10% in primary, and from 15 % to 30% of revision cases. Despite this, little is known of the outcome of treatment strategies for dislocation. In this study, we evaluated clinical results in patient undergoing revision THA for recurrent dislocation.
Materials and Methods
Twenty-four hips underwent revision THA for recurrent instability between 1998 and 2011 at our institution. Nine patients were male, and 15 were female. At the time of revision, the average age was 69.9 years (range, 45–83 years). Average follow-up was 29.8 months (range, 6–72 months). We recorded the number of times of dislocation, the direction of dislocation, the factor of dislocation and the operative strategy employed for each case. Demographic data and surgical treatment used were analyzed to determine risk factors for failure. We performed Mann-Whitney rank sum test, Student's t-test and Fisher exact test to evaluate the factors influencing failure. Significance was defined as a p value of <0.05 (Statistical Package for Social Sciences (SPSS) version 12.0 J for Windows (SPSS Inc., Chicago, IL, USA)).
Results
Before revision surgery, dislocation was occurred more than three times in all cases. The anterior dislocation was only four cases. In the factor of dislocation, 5 were malposition of implant, 11 were soft tissue imbalance, 3 were highly posterior tilting of pelvic and 5 were multi-factorial. Revision treatment included�liner and ball exchange in 19 hips, cup exchange in 5 hips. There was eight substitution to constrain liner for sever soft tissue imbalance. Nine (37.5%) had further dislocation. Cup revision for implant malposition was a successful method in recurrent instability (P=0.04). Constrain liner exchange (P=0.03) was associated with higher failure rate.
Conclusion
Recurrent dislocation has complex problems with multifaceted etiology that requires extensive preoperative planning of each dislocation factors and availability of multiple surgical options.
