CLASSIFICATION AND RECONSTRUCTION IN REVISION ACETABULAR ARTHROPLASTYWITH BONE STOCK DEFICIENCY

Revision acetabular surgery with bone stock loss is a difficult proble m, Defects are classified into contained cavitary (Type-1) defects and noncontained defects (Type 2A and 2B) based on preoperative radiograp hs and intraoperative findings, Fifty-four hips with Type-1 defects we re treated with morsellized allograft, The overall success rate was 90 % at 6.78 year followup, Type-2 defects are reconstructed with structu ral grafts, Twenty-nine hips with Type-2A defects (the allograft suppo rts <50% of the cup) mere reviewed at 7.1 years' followup, The success rate was 90%, In all but 1 case the allograft united to host bone, No resorption or minor resorption was seen in 26 of 29 hips with minor c olumn structural grafts, Type-2B defects all had structural allografts that supported >50% of the cup, There were 33 hips in this group obse rved for an average of 7.1 years, The rerevision rate in this group wa s 45%, However, 7 of 15 hips were reconstructed without additional gra ft at rerevision. The only factor that was clinically significant for success in Type-2B defects was choice of acetabular component, In hips that received roof rings with cemented cups, the success rate was 100 % (excluding 1 infection), The authors support the use of allograft bo ne in revision acetabular surgery, When structural grafts are required , every attempt should be made to achieve >50% support from host bone, If this is not possible, then a roof reinforcement ring with a cement ed cup is the acetabular component of choice.