The Journal of Bone and Joint Surgery, Vol 70, Issue 4 540-547, Copyright © 1988 by Journal of Bone and Joint Surgery, Inc
Effects of estrogen deficiency on the growth of tissue into porous titanium implants
RB Martin, HA Paul, WL Bargar, GA Dannucci and NA Sharkey
Orthopaedic Research Laboratories, University of California, Davis 95616.
The effect of systemic deficiency of estrogen on the growth of tissue into
porous titanium-fiber implants was studied in ovariectomized Beagle dogs.
Five dogs were ovariectomized and five dogs had a sham operation. After
waiting four months to allow the levels of circulating estrogen to decline,
a titanium-alloy implant that contained four surface pads of titanium-alloy
mesh was implanted in the proximal part of the humerus of each dog
bilaterally. Two months later, the implants were harvested and subjected to
a mechanical push-out test and quantitative histological study. The
push-out strength of the implants from the ovariectomized dogs was 31 per
cent less than in the control animals. Ovariectomy caused no difference in
the amount of ingrowth of bone but resulted in a significant increase in
the amount of fibrous connective tissue within the porous pads. The
presence of this fibrous tissue appeared to have an important effect on
bone-implant fixation: in the control dogs, strength correlated positively
with ingrowth of bone and negatively with ingrowth of fibrous tissue,
whereas in the ovariectomized dogs, strength correlated positively with
ingrowth of fibrous tissue and not at all with ingrowth of bone.