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General Joint Surgery Information
What Is The Difference Between Cemented
And Non-Cemented Fixation Of Your Total Joint Prosthesis?
Roger Emerson, Jr., M.D.
There are two competing means of securing a joint prosthesis
to the bone, with and without cement. Historically the first
joint implants, which were developed to replace the ball of
the hip after a fracture, were secured by press fitting the
implant into the bone. As you can imagine, this was good if
the fit was tight enough and the bone was strong enough to accept
the implant. Inactive patients did the best, and since this
type of fixation was used predominantly in the elderly, it was
satisfactory in most cases and continues to be used today.
Cementing of the prosthesis to the bone was a real improvement
because it made fixation of the implant more reliable, especially
in weaker bone, and since the fixation was immediate, the patient
was able to function more quickly. About half of all implants
are cemented today. Concern arose in the mid-1980s as to the
durability of cement fixation when we began seeing failure of
the cement bond to the implant.
There were two responses to this concern. One group of surgeons
developed bone ingrowth technology whereby the bone actually
grows into the implant itself, eliminating the need for cement.
Another group of surgeons developed a better cementing method.
Both of these methods are widely used today. Generally speaking,
younger, more active patients will have a bone ingrowth prosthesis,
and older, less active patients will have a cemented prosthesis.
After a failed implant, and therefore, a "revision"
situation, bone ingrowth implants appear to be more consistent.
The bone ingrowth biology is similar to fracture healing,
which takes time to occur and requires protected weightbearing.
There are a number of exceptions to these generalities, so it
is best to discuss your individual case with your doctor if
you have any questions.
Research is very active in this area of orthopaedic surgery
and this newsletter will keep you informed of changes in the
field as they occur.
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