Analysis of Temporal Wear Patterns of Porous-Coated Acetabular Components: Distinguishing Between True Wear and So-Called Bedding-in* by CHRISTI J. SYCHTERZ, C. ANDERSON ENGH, ANTHONY YANG, and CHARLES A. ENGH J Bone Joint Surg Am Volume 81(6): June 1, 1999 1999 by The Journal of Bone and Joint Surgery, Inc. Fig. 1 Photographs showing the Arthropor cup (Joint Medical Products, Stamford, Connecticut), which has a porous-coated titanium shell and a hemispherical polyethylene liner. CHRISTI J. SYCHTERZ et al. J Bone Joint Surg Am 1999;81: 1999 by The Journal of Bone and Joint Surgery, Inc. Fig. 2 Photographs showing the Tri-Lock cup (DePuy, Warsaw, Indiana), which has a porous- coated titanium shell with a hemispherical outer geometry and a cylindrical inner geometry. CHRISTI J. SYCHTERZ et al. J Bone Joint Surg Am 1999;81: 1999 by The Journal of Bone and Joint Surgery, Inc. Fig. 3 Photographs showing the Harris-Galante cup (Zimmer, Warsaw, Indiana), which has a fiber-mesh-coated titanium shell and a hemispherical polyethylene liner. CHRISTI J. SYCHTERZ et al. J Bone Joint Surg Am 1999;81: 1999 by The Journal of Bone and Joint Surgery, Inc. Fig. 4 Photographs showing the Duraloc cup (DePuy), which has a porous-coated titanium shell and a hemispherical polyethylene liner that is held in the shell with a metal locking ring. CHRISTI J. SYCHTERZ et al. J Bone Joint Surg Am 1999;81: 1999 by The Journal of Bone and Joint Surgery, Inc. Fig. 5 Graph showing how temporal measurements of penetration by the femoral head can be used to estimate both true wear and bedding-in. CHRISTI J. SYCHTERZ et al. J Bone Joint Surg Am 1999;81: 1999 by The Journal of Bone and Joint Surgery, Inc. Fig. 6 Graph showing the mean amount of penetration by the femoral head over time in association with the first-generation acetabular components. CHRISTI J. SYCHTERZ et al. J Bone Joint Surg Am 1999;81: 1999 by The Journal of Bone and Joint Surgery, Inc. Fig. 7 Graph showing the mean rate of penetration by the femoral head over time in association with the first-generation acetabular components. CHRISTI J. SYCHTERZ et al. J Bone Joint Surg Am 1999;81: 1999 by The Journal of Bone and Joint Surgery, Inc. Fig. 8 Graph showing the results of multiple linear regression analysis of the data on penetration by the head for the three different first-generation acetabular cups. CHRISTI J. SYCHTERZ et al. J Bone Joint Surg Am 1999;81: 1999 by The Journal of Bone and Joint Surgery, Inc. Fig. 9 Graph showing the results of multiple linear regression analysis of the data on penetration by the femoral head for a second-generation acetabular component (the Duraloc cup) compared with the three first-generation acetabular components (the Arthrop... CHRISTI J. SYCHTERZ et al. J Bone Joint Surg Am 1999;81: 1999 by The Journal of Bone and Joint Surgery, Inc.