Purpose: The management of severe acetabular bone deficiency and a stable femoral stem can be a challenging problem in revision hip surgery. Replacement of both the acetabular and femoral component in elderly patients can increase perioperative risks without the certainty of a better functional outcome. We report the long-term outcome of reinforcement rings in isolated acetabular revision to determine whether this procedure allows hip function restoration and implant longevity.
Methods: A retrospective study was conducted to evaluate the long-term results of isolated acetabular revision in thirty patients with a mean age of 70.6 years. 16 patients (16 hips) received an acetabular reinforcement ring, and 14 patients received a reconstruction cage. Acetabular defects were classified as Paprosky Type II in 16 cases and Type III in 14 cases. The mean follow-up was 11.3 years (range 10-15 years).
Results: Radiographic signs of loosening were found in 9 cases (30%). 4 cases (13.3%) with severe osteolysis and implant migration underwent further revision surgery. All 30 unrevised femoral stems were considered stable. 1 (3%) early dislocation, was conservatively treated. Clinical assessment showed a significantly improved mean Harris Hip Score from 45.1 points preoperatively to 85.4 at the latest follow-up (p < 0.05). The 15-year survival rate was 86.7%.
Conclusions: Our long-term results showed that in selected patients, isolated acetabular revision with rings or antiprotrusio cages represents a reasonable surgical technique for the management of severe acetabular bone loss. However, concerns about the high radiographic loosening rates are possibly related to low bone ingrowth compared to new porous implants.
Keywords: Acetabular defects; aseptic loosening; isolated acetabular revision; reconstruction cages; reinforcement rings; revision hip arthroplasty.