3-D Computed Tomography as an Assessment of Periacetabular Osteolysis in Revision Total Hip Arthroplasty

초록

Purpose This study was performed to determine the usefulness of three-dimensional computed tomography (3D CT) in measuring periacetabular osteolysis by comparing the real volume of osteolysis in revision surgery and polyethylene wear on plain radiographs analyzed with a computer vector wear analysis program. Materials and Methods Twenty-three patients who had undergone revision surgery due to periacetabular osteolysis from January 2006 to November 2011 at our hospital were enrolled in this study. All patients received primary cementless total hip arthroplasty between May 1994 and July 2005 at the same hospital. All patients had well functioning total hip arthroplasty and followed-up regularly at our hospital and met the following inclusion criteria: (1) there was evidence of periacetabular osteolysis on plain radiographs, (2) there was no evidence of acetabular cup loosening, (3) all patients received revision surgery due to massive osteolysis on 3D CT. We excluded the patients who had septic osteolysis or aseptic osteolysis with implant loosening. Linear and volumetric wear of polyethylene liners were measured with a computer assisted vector wear analysis program. We measured the volume of periacetabular osteolysis in 3D CT using Rapidia 3D software version 2.8 algorithms before the revision surgery. Intraoperative real osteolytic volume was calculated as the sum of the volumetric increments of the acetabular cup and impacted cacellous bone volume in proportion to 1.8g/cm3. Results Linear regression analysis showed a weak correlation (r=0.18 and 0.339, P=0.938 and 0.123) between the mean linear and volumetric wear rate of polyethylene liners measured on plain radiographs and osteolytic volume measured on 3D CT. A weak correlation was also found between the mean linear and volumetric wear rate of polyethylene liners and intraoperative real osteolytic volume (r: 0.206 and 0.242, P= 0.359, 0.277), and between osteolytic volume measured on 3D CT and impacted