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*Email: sgh_iizu@grn.janis.or.jpAbstractBACKGROUND: Acetabular defects are encountered in both primary total hip arthroplasty(THA) in patients with developmental dysplasia of the hip (DDH) and in revision THA. Thepurpose of this study was to evaluate the clinical and radiographic results of one method ofacetabular reconstruction for THA using a hydroxyapatite (HA) block with either an autogenousgraft or allograft of impacted morsellized bone in conjunction with a cemented socket.METHODS: Fourteen hips in 14 patients (all female; average age, 64 years) were treated withthe above technique in primary (11 DDH) or revision THA (three loosened sockets). Allpatients were followed clinically in a prospective fashion, and radiographs were analyzedretrospectively. One initial patient had 16-year follow-up, whereas the remaining 13 patientshad follow-up between four and 5.5 years. RESULTS: No acetabular components were revised,including the socket of 16-year postoperative case which remains rigidly fixed and supported bythe graft and HA block with only mild polyethylene wear and minor osteolysis. The meanJapanese Orthopaedic Association (JOA) score for the hips improved from 37 pointspreoperatively to 90 points postoperatively. CONCLUSIONS: The authors report very goodresults of acetabular reconstruction with the use of these biomaterials in conjunction withimpaction morsellized bone graft in THA. Osteointegration and good clinical outcome wereachieved in all of cases. However longer-term outcome should be the subject of furtherinvestigation, as the majority of these patients had only mid-term follow-up of 4 to 5.5 years.Acetabular bone defects, especially proximal, lateral acetabular bone deficiency, present one ofthe more difficult technical problems associated with primary total hip arthroplasty (THA) inpatients with developmental hip dysplasia (DDH) and in cases of acetabular bone loss inrevision THA. The greater the extent of the coverage of the acetabular component by bonegraft, the greater the rate of late failure. 1 Faced with the difficulties of the previous operativetechniques, the authors developed a new shaped biomaterial, a hydroxyapatite (HA) block, toassist in the reconstruction of acetabular bone defects. The biomaterial consisted of a solidblock of HA with porous aspects for promoting rigid bony fixation through osteoconduction.The advantages of the HA block are: (1) increased strength and flexibility properties comparedto bone, providing structural support for the morsellized bone graft while preventing collapse ofthe bone graft during the incorporation period; and (2) simplification of surgical technique byeliminating the need to trim and shape a bulk bone graft.The purpose of this study was to evaluate the clinical and radiographic results of the method ofacetabular reconstruction in THA using a cemented socket in conjunction with an HA blockgraft with impaction morsellized bone graft.Patients and MethodsPatients with lateral acetabular defects were selected for participation in this study if thecoverage of the socket by the graft would be expected to be 50 % or more if the bulk femoralhead graft were conventionally used. As a result, the patients had either moderate/severedysplasia or dislocation of the acetabulum at time of primary THA or an acetabular roof defectin revision cases. The defects were classified preoperatively according to the classificationsystems of Crowe 2 for primary cases or the system of D’Antonio (AAOS) 3,4 for revision. TheCrowe classification of hip subluxation or dislocation was Group II for two hips, Group III forsix, and Group IV for three (Table 1). All of the hips for revision were classified Group III(combined superior segmental and superior cavitary defect) by the D’Antonio (AAOS)classification (Table 1).Fourteen hips in 14 patients (all female; average age, 64 years) with 11 DDHs and threeloosened sockets were treated with primary and revision THA, respectively. The patients werefollowed up clinically using the Japanese Orthopaedic Association (JOA) score 5 in aprospective fashion, and radiographs were analyzed retrospectively. One initial case had 16-file:///E|/ISTA2010-Abstracts.htm[12/7/2011 3:15:47 PM]