Constrained acetabular components in complex revision total hip arthroplasty.

UNLABELLED: We retrospectively reviewed 39 consecutive hips in 38 patients to examine the outcome of acetabular fixation and stability in patients with the tripolar constrained acetabular component who had complex revision surgery at 2 to 5 years of followup. Preoperative indications included recurrent dislocation, loose acetabular component with instability, migrated bipolar, resection arthroplasty conversions, and primary arthroplasty. Postoperative radiographs were reviewed for radiolucencies, loosening, migration, or breakage. The patients' average age was 65 years (range, 44-83 years). Thirty-five of the 39 acetabular components (91%) are well fixed and bony ingrown. There were no dislocations. One patient was involved in an motor vehicle accident 1 year postoperatively and sustained a fracture of the ilium and a 2 mm radiolucency about the component which is now stable. Three patients had acetabular revisions. Two patients were revised to a tripolar cemented into a cage and are doing well. The tripolar constrained acetabular component offers reliable fixation and joint stability in patients at high risk for dislocation in this short term followup.

LEVEL OF EVIDENCE: Therapeutic study, Level IV (case series). See the Guidelines for Authors for s complete description of levels of evidence.