Minimal radiation dose computed tomography for measurement of cup orientation in total hip arthroplasty.

We studied a computed tomography (CT) protocol with minimal radiation dose for measurements of cup orientation after total hip arthroplasty. Inclination and version angles were measured directly on cadaver pelvis fixed with an acetabular component. We performed the CT scanning on the phantom made of this model in 6 protocols as follows: tube current of 300, 100, 50, 30, 20, and 10 mA. The 30 mA protocol maintained good image quality for measurements with the smallest dose (1.1 millisievert), which corresponds to less than 2 times that of an anteroposterior radiograph of the pelvis. The differences of measured angles between direct and CT measurements on the phantom were less than 1 degrees. Measurements of cup orientation were possible by this protocol in 26 hips in 22 patients after total hip arthroplasty.

[1]  D. Murray.  The definition and measurement of acetabular orientation. , 1993, The Journal of bone and joint surgery. British volume.

[2]  F M Rodriguez y Baena,et al.  Very low-dose computed tomography for planning and outcome measurement in knee replacement. The imperial knee protocol. , 2006, The Journal of bone and joint surgery. British volume.

[3]  Frank Langlotz,et al.  Anatomic Referencing of Cup Orientation in Total Hip Arthroplasty , 2005, Clinical orthopaedics and related research.

[4]  J. Lewis,et al.  Dislocations after total hip-replacement arthroplasties. , 1978, The Journal of bone and joint surgery. American volume.

[5]  B. Zurfluh,et al.  Compliant positioning of total hip components for optimal range of motion , 2004, Journal of orthopaedic research : official publication of the Orthopaedic Research Society.

[6]  Chiou-Shann Fuh,et al.  A New Tool for Measuring Cup Orientation in Total Hip Arthroplasties from Plain Radiographs , 2006, Clinical orthopaedics and related research.

[7]  M. Kalra,et al.  Do metallic endoprostheses increase radiation dose associated with automatic tube-current modulation in abdominal-pelvic MDCT? A phantom and patient study. , 2005, AJR. American journal of roentgenology.

[8]  K. Soffe,et al.  Effect of acetabular component orientation on recurrent dislocation, pelvic osteolysis, polyethylene wear, and component migration. , 1998, The Journal of arthroplasty.

[9]  B F Morrey,et al.  Dislocations after total hip arthroplasty. , 1982, The Journal of bone and joint surgery. American volume.

[10]  M Tannast,et al.  Tilt and Rotation Correction of Acetabular Version on Pelvic Radiographs , 2005, Clinical orthopaedics and related research.