Twenty-three patients (27 cups) required rerevision for any cause at a mean time-to-rerevision of 6.9 years (range, 0.1–23). The cup rerevision rate was 32%. The causes for cup failure were aseptic loosening or osteolysis (22), infection (two), dislocation (one), graft nonunion (one), and acetabular component fracture (one). The treatment for cup failure included cup-only exchange (12), cup rerevision with structural allograft, cage or metal augment (12), excision arthroplasty (two) and two-stage revision arthroplasty (one).
Fifteen patients had graft failures at a mean time to rerevision of 6.1 years (range, 0.5–23). The graft failure rate was 18%. Causes for graft failure included aseptic loosening or osteolysis (11), infection (two), acetabular component fracture (one), and graft nonunion (one). Treatments included minor column graft (six), major column graft (four), metal augment (one), excision arthroplasty (two), trabecular metal cup-cage reconstruction (one), and two-stage revision arthroplasty (one). The 2-stage revision and one of the excision arthroplasties were performed for infection.
The 15- and 20-year Kaplan-Meier survivorships for cup were 61% and 55% with the end point defined as rerevision for any cause (Fig. ). With the end point defined as rerevision for aseptic loosening, the survivorships were 67% and 61% (Fig. ). The 15- and 20-year Kaplan-Meier survivorships for graft were 78% with the end point defined as rerevision for any cause (Fig. ). With the end point defined as rerevision for nonseptic failure, the 15- and 20-year survivorships were 81% (Fig. ).
Kaplan-Meier survivorship is shown for cup with revision for any cause as the end point.
Kaplan-Meier survivorship is shown for cup with revision for aseptic loosening as the end point.
Kaplan-Meier survivorship is shown for graft with revision for any cause as the end point.
Kaplan-Meier survivorship is shown for graft with revision for aseptic loosening as the end point.
All grafts healed radiographically with trabecular bridging at the graft–host junction except for one. All patients had resorption except for seven (17.5%). Graft resorption was considered mild in 28 patients (70%), moderate in three (7.5%), and severe in two (5%). There were six cup rerevisions and one graft failure in patients with mild resorption at a minimum followup of 4.4 years (mean, 16.2 years; range, 4.4–24.8 years) (one case was included with less than 5 years followup because of cup and graft failure). None of the three patients with moderate graft resorption had rerevision at a minimum followup of 11 years (mean, 14.7 years; range, 11–22). The two patients with severe resorption had graft failure and rerevision at 4 and 23 years after the index surgery. Cup migration occurred in 18 patients. Ten patients migrated less than 3 mm, of which there were three cup rerevisions, including one graft failure. Five had migrated between 3 and 5 mm but subsequently stabilized and did not required rerevision surgery. Three patients had migrated more than 5 mm and underwent rerevisions. Of the 25 patients for whom radiographs of the graft were not available for assessment, there were 19 cup failures, which included 13 graft failures that were mostly rerevised in the 1980s and 1990s.
The mean modified Harris hip score was 40.5 (range, 20–60) before surgery, 72.8 (range, 40–95) at 1 year after surgery and 73.1 (range, 26–93) at last followup assessment.
Associated complications included three dislocations treated with closed reduction, three nerve injuries that resolved with nonoperative treatment, and one minor column fracture during reduction that was treated nonoperatively without further complications. There was one intraoperative death from vascular complications despite pelvic angiography and iliac vessel embolization. This was due to screw placement outside the ‘safe zone’ [12