What Is the Survivorship of Revision Surgery Performed for the Chronically Dislocated THA?

Abstract

Instability remains one of the most common indications for revision THA. However, little is known about the efficacy of surgery for and the complications associated with revision THA for patients with a chronically dislocated THA, which we define as a dislocation of more than 4 weeks. For patients with a chronically dislocated THA undergoing revision THA, we asked (1) What is the survivorship free from additional revision for these procedures? (2) What complications are associated with revision THA in this setting? (3) What are the clinical outcomes as measured by the Harris hip score in these procedures? From 1998 to 2014, 1084 patients who underwent revision THA for instability were reviewed and 33 patients (33 hips) were identified who had a hip that had been dislocated for more than 4 weeks. Median time dislocated was 4 months (range, 1-120 months), and the mean distance of the femoral head above hip center at presentation was 45 mm. Mean patient age was 67 ± 17 years, and 79% of patients (26 of 33) were women. During the period in question, we used four approaches: Treatment with acetabular component revision in 18 of 33 patients (55%), head and liner exchange in nine patients (27%), both-component revision in five patients (15%), and isolated femoral component revision in one patient (3%). A constrained liner was used in 17 patients (52%), including six of the patients treated with acetabular component revision, and three of those who had both-component revisions. During the period in question, our general indications were hip pain and/or unacceptable function with the chronically dislocated prosthesis. Our sample size was too small to evaluate the association of the procedure choice on survivorship or complication risk. We used Kaplan-Meier survivorship analysis to estimate survivorship free from complication, reoperation, or revision. Mean followup was 4.4 years (range, 2-10 years). Survivorship free from any revision, complication, or reoperation was 61% at 5 years (95% CI, 43-82). Survivorship free from revision was 83% at 5 years (95% CI, 67-98). Etiology for revision was aseptic loosening in three of 33 hips (9%), recurrent dislocation in two hips (6%), and deep periprosthetic joint infection in two hips (6%). Five complications (15%) did not result in a reoperation, including one dislocation and one incomplete peroneal nerve palsy in a patient after an anterolateral approach. The Harris hip score improved from mean 50 ± 17 preoperatively to mean 80 ± 11 at 5 years. Chronically dislocated THAs can be successfully managed with revision THA. We recommend close evaluation of the components for aseptic loosening, performing revision surgery only on patients with pain and poor function, and thoroughly counseling patients that survivorship is modest and complications are common. Level IV, therapeutic study.