OBJECTIVESTo evaluate the medium-term clinical results of reconstruction of the severe acetabular bone defect by using metal mesh and impaction bone grafting (IBG) technique, as well as to emphasize the importance of Paprosky acetabular bone defect classification system in assessing the severity of bone defect and to analyse the failure reasons.

METHODSBetween December 1998 and December 2007, 67 total hip arthroplasty (THA) revisions were made by using IBG technique to reconstruct severe acetabular bone defects combining with metal mesh or meta mesh cup on 63 patients. All the defects were combined defect (AAOS Type 3). There were 20 Paprosky II B defects in 19 patients, 28 Paprosky II C defects in 29 patients and 13 Paprosky II A defects in 12 patients. Regular follow-ups, involving the assessments of Harris hip scoring system, clinical efficacy, imaging and complications, were subsequently made.

RESULTSSixty-one hips in 58 patients gained an average of 63 months (8-107) follow-up. Harris hip score increased from an average of 41.7 points (21-52) preoperatively to an average of 89.2 points (81-98) at the last follow-up, with an excellent and good rate of 93%. Radiographically, there were no loosening cases excluding the 3 dislocated polyethylene cups from the metal mesh cups. One case was failed to reconstruction the height of normal hip center, in which metal mesh cup was used for enforce the medial wall. Dislocations occurred in 3 hips, 1 of these patients required an open reduction and the other 2 dislocations only need close reduction. Postoperative infection rate was 1.6% (1 case), two stage revision with another IBG procedure succeeded in this patient.

CONCLUSIONSIBG combing with metal mesh for reconstruction of severe acetabular bone defect is an ideal technology. Paprosky acetabular bone defect classification system is very important in IBG procedure besides AAOS acetabular bone defect classification system to evaluate the severity of bone defect and to compare the outcomes between different authors. The use of metal mesh cup should be avoided to enforce acetabular medial wall in patients with severe acetabular bone defect.