Hip instability in 2-stage reimplantation without an articulating spacer.

Hip instability is a common postoperative complication after revision surgery. This study sought to define the prevalence of hip instability after 2-stage reimplantation without an articulating spacer. A joint registry review identified 110 patients undergoing 2-stage reimplantation. Fifty-five patients (56 hips) were alive at the time of data collection. Instability was documented and risk factors were analyzed. Of the 56 hips, 14 (25%) dislocated. Five of these 14 patients had chronic abduction insufficiency. Six patients required rerevision to attain stability. There were no significant differences between dislocators and nondislocators in abduction angle, head size, cup size, liner type, or leg length. The 25% (14/56) dislocation rate reported here is unacceptable. Interim articulating spacers, postoperative bracing, large head technology, and constrained liners are treatment methods that should be considered in this group of patients.