The Survivorship of Protrusio Cages for Metastatic Disease Involving the Acetabulum

Abstract

Metastatic disease commonly affects the proximal femur and occasionally the acetabulum. Surgical options include the use of a protrusio cage with a THA. However, the complications and survivorship of these cages for this indication is unknown. The purpose was to report the restoration of function, complications and implant survival. The medical records of 29 patients undergoing insertion of a protrusio cage for metastatic pelvic disease were reviewed. Complications were recorded. The most common diagnosis was metastatic breast cancer. During the review process, all but 10 of the 29 patients died 1-73 months after surgery. The median length of survival was 12 months (range, 3 days-100 months) after the procedure; 11 patients were alive at last followup at a median of 16 months (range, 1-100 months). One patient had loss of fixation owing to disease progression. Five patients had dislocations, four of which were treated. There were three deep infections (two that led to dislocation, which proceeded to revision surgery). Ten patients of the 29 patients became household ambulators, 17 became community ambulators, two remained chair-bound, and one bed-bound. The protrusio cage allowed most patients to return to walking with only one mechanical failure.