[Use of bulky, femoral head allografts in revision hip arthroplasty for acetabular component aseptic loosening].

The aim of the study was to analyze results in patients treated with frozen, bulky femoral head allografts without reinforcement ring for significant bone lost after acetabular component aseptic loosening. Retrospective analysis was done on 19 patients in the average age of 58 years. There were 13 women in this group. Acetabular bone lost was classified as IIIa or IIIb according to Paprosky. For revision 10 cemented and 9 uncemented cups were used. Mean coverage of acetabular component by graft on antero-posterior radiographs was 52% (from 30% to 100%). The mean follow-up was 4.2 years. Seven of our patients required another revision for aseptic loosening of the cup. The remaining 12 patients had satisfactory clinical and radiological result. The function improved from 35 points before operation to 76 at last follow-up according to Harris grading system (minimum improvement was 20 points). Two of the patients had radiographic signs of osteolysis around implant, without symptoms of loosening. Coverage of acetabular cup by the graft was 65% in cases of loosening and 42% in those patient without loosening (p <0.01). There was no statistical relationship between age and frequency of loosening (p > 0.05). Bulky, femoral head allografts are passive scaffold and may lose the mechanical strength. In cases of big bone defects of supero-lateral part of acetabulum use of metal reinforcement rings should be considered.