Alterations in femoral strain, micromotion, cortical geometry, cortical porosity, and bony ingrowth in uncemented collared and collarless prostheses in the dog.

The effects of a collared femoral endoprosthesis in uncemented total hip arthroplasty were evaluated in 12 dogs. This experimental study compared the biomechanic and histologic responses between collared and collarless femoral prostheses 4 months after implantation. Implant stability (micromotion) and cortical surface strain were evaluated immediately and 4 months after implantation in a simulated postoperative condition, whereas bone ingrowth, cortical porosity, and cortical remodeling were assessed after 4 months only. There were no significant differences in implant stability or cortical surface strains when the collared and collarless groups were compared acutely or after 4 months (P > .05). There were also no significant differences in percent fill, bony ingrowth, or cortical geometry after 4 months (P > .05). There was a significant increase in cortical porosity measured from the proximal femur after 4 months for both the collared (P = .0002) and collarless groups (P = .009) and when both groups were compared (collarless, 8.2% and collared, 5.8%; P = .03). The results suggest that a collar may be beneficial in decreasing the cortical remodeling that occurs in the proximal femoral cortex after implantation of an uncemented total hip arthroplasty.

[1]  J L Lewis,et al.  The influence of prosthetic stem stiffness and of a calcar collar on stresses in the proximal end of the femur with a cemented femoral component. , 1984, The Journal of bone and joint surgery. American volume.

[2]  S D Cook,et al.  A comparison of three varieties of noncemented porous-coated hip replacement. , 1990, The Journal of bone and joint surgery. British volume.

[3]  W H Harris,et al.  Is It Advantageous to Strengthen the Cement‐Metal Interface and Use a Collar for Cemented Femoral Components of Total Hip Replacements? , 1992, Clinical orthopaedics and related research.

[4]  K. Markolf,et al.  The effect of calcar contact on femoral component micromovement. A mechanical study. , 1980, The Journal of bone and joint surgery. American volume.

[5]  P. Manley,et al.  Femoral Strain Adaptation after Total Hip Replacement: A Comparison of Cemented and Porous Ingrowth Components in Canines , 1990, Proceedings of the Institution of Mechanical Engineers. Part H, Journal of engineering in medicine.

[6]  D R Pedersen,et al.  An analysis of collar function and the use of titanium in femoral prostheses. , 1981, Clinical orthopaedics and related research.

[7]  W H Harris,et al.  Proximal strain distribution in the loaded femur. An in vitro comparison of the distributions in the intact femur and after insertion of different hip-replacement femoral components. , 1978, 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]  D R Sumner,et al.  Remodeling and ingrowth of bone at two years in a canine cementless total hip-arthroplasty model. , 1992, The Journal of bone and joint surgery. American volume.

[10]  L. Whiteside,et al.  The effect of collar and distal stem fixation on micromotion of the femoral stem in uncemented total hip arthroplasty. , 1989, Clinical orthopaedics and related research.

[11]  P. Manley,et al.  Vascular and morphologic changes in canine femora after uncemented hip arthroplasty. , 1993, Veterinary surgery : VS.

[12]  J. M. Lee,et al.  Observations on the Effect of Movement on Bone Ingrowth into Porous‐Surfaced Implants , 1986, Clinical orthopaedics and related research.

[13]  C. F. Abrams,et al.  Subsidence of an uncemented canine femoral stem. , 1992, Veterinary surgery : VS.