Computed Tomography Reconstruction from Hollow Projections

Abstract

The long-term mechanical stability of total hip arthroplasties limits the application of this widely used surgical procedure in cases of severe coxarthroses. A noninvasive method of assessing the tissue distribution in the vicinity of the implant-bone interface is needed to identify early signs of implant loosening and to evaluate new prosthetic solutions. To develop such a method, a modified computed tomography technique was devised that yields cross-sectional images without the usual artifacts caused by metallic implants. This technique provides information on bone mineral and bone cement distributions and on the precise position and orientation of the implant within the femur shaft. Results obtained from excised human femurs and preliminary data from measurements on patients made 3 mo. postoperatively reveal that the bone cement distribution is much less favorable than is indicated by radiographs.