Influence of Porous Coating Level on Proximal Femoral Remodeling: A Postmortem Analysis

This study used femurs retrieved at autopsy to compare the extent and location of bone remodeling between four patients implanted with proximally porous coated femoral prostheses and a matched group of four patients implanted with extensively porous coated femoral prostheses. The femoral components studied were large, cementless, straight, cobalt chrome stems and were identical except for the amount of porous coating. The contralateral normal femur of each patient also was retrieved, implanted with an identical prosthesis, and used as a control for bone mineral content. Dual energy xray absorptiometric analysis showed marked loss of bone mineral content in both groups of patients. The extensively coated group had less bone loss on average (18.4%) than did the proximally coated group (38.6%). There was no relationship between the extent of coating and the location of bone mineral loss; specifically, proximal coating did not protect against loss of bone mineral content proximally or distally in the femur. Videodensitometric analysis of cross sections of periprosthetic bone also showed that the extensively coated group tended to have less decrease in bone density than did the proximally coated group (14.3% versus 28.4%). Although one cannot presume that all proximally fixed stem designs would produce results similar to those presented here, these findings show that decreasing the extent of porous coating alone does not necessarily reduce proximal femoral bone loss.

[1]  D. Hungerford,et al.  Proximally coated ingrowth prostheses. A review. , 1997, Clinical orthopaedics and related research.

[2]  C. Engh,et al.  Long-Term Clinical Consequences of Stress-Shielding after Total Hip Arthroplasty without Cement* , 1997, The Journal of bone and joint surgery. American volume.

[3]  W J Maloney,et al.  The Otto Aufranc Award. Skeletal response to well fixed femoral components inserted with and without cement. , 1996, Clinical orthopaedics and related research.

[4]  C. Engh,et al.  The Influence of Clinical Factors on Periprosthetic Bone Remodeling , 1996, Clinical orthopaedics and related research.

[5]  PhD Rik Huiskes,et al.  Preclinical testing of total hip stems. The effects of coating placement. , 1995, Clinical orthopaedics and related research.

[6]  C. Engh,et al.  Roentgenographic densitometry of bone adjacent to a femoral prosthesis. , 1993, Clinical orthopaedics and related research.

[7]  J O Galante,et al.  Primary total hip reconstruction with a titanium fiber-coated prosthesis inserted without cement. , 1993, The Journal of bone and joint surgery. American volume.

[8]  D R Sumner,et al.  Experimental studies of bone remodeling in total hip arthroplasty. , 1992, Clinical orthopaedics and related research.

[9]  Engh Ca,et al.  The influence of stem size and extent of porous coating on femoral bone resorption after primary cementless hip arthroplasty. , 1988 .

[10]  J. Galante,et al.  Determinants of stress shielding: design versus materials versus interface. , 1992, Clinical orthopaedics and related research.

[11]  C. Engh,et al.  Producing and avoiding stress shielding. Laboratory and clinical observations of noncemented total hip arthroplasty. , 1992, Clinical orthopaedics and related research.

[12]  C. Engh,et al.  The influence of stem size and extent of porous coating on femoral bone resorption after primary cementless hip arthroplasty. , 1988, Clinical orthopaedics and related research.

[13]  J. Szivek,et al.  The effect of proximally and fully porous‐coated canine hip stem design on bone modeling , 1987, Journal of orthopaedic research : official publication of the Orthopaedic Research Society.