The Journal of Bone and Joint Surgery, Vol 72, Issue 8 1220-1229, Copyright © 1990 by Journal of Bone and Joint Surgery, Inc
Histomorphological studies of the long-term skeletal responses to well fixed cemented femoral components
M Jasty, WJ Maloney, CR Bragdon, T Haire and WH Harris
Department of Orthopaedic Surgery, Massachusetts General Hospital, Boston 02114.
Thirteen femora that were obtained at autopsy from patients in whom a
cemented total hip replacement had been implanted from forty months to 17.5
years earlier were evaluated radiographically and morphologically. All of
the patients had been functioning well, and only one of the prostheses
showed radiographic evidence of loosening. Serial sections of the proximal
portion of the femur that enclosed the femoral component of the prosthesis
showed that the host bone was intimately and directly apposed to the
cement, and fibrous tissue intervened only rarely. The bone-remodeling
processes had created a dense shell of substantial new bone around the
cement-mantle that resembled a new cortex, attached to the outer cortex by
new trabecular struts. Evidence of ingrowth of bone from this dense shell
of bone into the undulating surface of the cement was found in many areas.
In the adjacent femoral cortex, there was substantial osteoporosis and
cortical thinning. The cement-bone interface was intact and excellent
throughout, despite the presence of fractures within the cement-mantle and
de-bonding at the cement-prosthesis interface in some specimens. The
cemented femoral components were well tolerated by the skeleton over a long
period of use, and fibrous tissue had rarely formed at the femoral
cement-bone interface of these well fixed and clinically successful
prostheses. The cement-mantle was well supported by extensive medullary
bone-remodeling and formation of a dense shell of new bone. The internal
bone-remodeling helped to maintain the cemented femoral components over
time and did not cause loosening of the prosthesis.