High body mass index is associated with increased risk of implant dislocation following primary total hip replacement: 2,106 patients followed for up to 8 years.

BACKGROUND AND
PURPOSE: Implant dislocation is one of the commonest complications following primary total hip replacement (THR). We investigated the effect of body mass index (BMI) and tobacco use on the risk of this complication. SUBJECTS AND METHODS: Through linkage between the Swedish Construction Workers' cohort and the Swedish Inpatient Register, 2,106 male patients who had undergone primary THR between 1997 and 2004 were identified. We used Cox multivariable regression analysis to study the association between BMI and tobacco use and the risk of implant dislocation.
RESULTS: 53 patients (2.5%) developed implant dislocation during a mean of 2 (0-3) years of follow-up. We found overweight and obesity to be associated with increased risk of implant dislocation (HR = 2.5,95% CI: 1.1-5.5 and HR = 3.7, 95% CI: 1.5-9.3, respectively as compared to those of normal weight). There was no statistically significant association between tobacco use and the risk of dislocation.
INTERPRETATION: Greater attention should be given to high BMI as a risk factor for implant dislocation following THR.