Bone impaction grafting and anti-protrusio cages in high-grade acetabular defects: a 22-year single centre experience

Purpose Report clinical and radiological long-term follow-up (FU) outcome of bone impaction grafting (BIG) and anti-protrusio cage (APC) technique in hip revision surgery. Materials and methods We analysed data on complications, as well as the clinical and radiological outcome of patients treated using this technique at our institution. We evaluated the acetabular bone stock renovation, acetabular component stability and its radiological migration. The clinical parameters considered were the Visual Analogue Scale (VAS) and the modified Harris Hip Score (mHHS). Results Forty hips, with a mean 14.3-year FU, were included. This technique showed good clinical long-term results in an elderly and low-demanding population (mean age at surgery 71.4 +/- 12.1 years). The radiological results were not as good as clinical results: 67.5% of cases had a radiographic evidence of resorption of less than 1/3 of the bone graft; 27.5% had a resorption ranging from 1/3 and 1/2 of the graft, and 5% had more than 1/2 of the graft. Paprosky type III B reported worse results in terms of graft resorption and a greater migration of the APC (p < 0.001). The survival rate was 95% and a 2.5% rate of septic failure was recorded. Conclusion Impaction grafting with femoral head and APC is an effective technique for treating high-grade acetabular defects. APC reconstructs the hip centre of rotation, avoiding loading forces on the underlying bone graft that can be correctly integrated. At long-term FU, satisfactory clinical results, not strictly correlated to radiological signs of integration, were observed; Paprosky type III B reported worse results in terms of graft resorption and a greater migration of the APC.