A recent Associated Press article regarding the approval of surface replacement in the United States has raised interest on the part of many perspective total hip patients regarding surface replacement. The article touts this procedure as something of value in the younger patient who is going to require a total hip replacement.
Surface replacement has been around for more then 30 years. In the past, it has never been as successful or has had as good a longevity as total hip replacement. With a change from a metal-on-polyethylene bearing to a metal-on-metal bearing, it is hoped that issues of wear have been solved and, because of the large head size, better motion and a lower dislocation rate has been advocated. Another potential advantage is preservation of the proximal femoral bone that can be useful at the time of a revision procedure.
When you break down these potential advantages, most of them fade away when you compare them to modern metal-on-metal total hip replacements. With the advent of large head total hip replacement, the benefit of increased range of motion and decreased dislocation rate is all but eliminated when comparing surface replacement to total hip replacement. Stating that these are better for young active patients simply ignores the data that is available in the literature. Lastly, stating that it preserves proximal bone, which in fact it can, is not a major factor in revision surgery. More importantly, loss of bone on the socket side, which can be associated with surface replacement, is a much more challenging problem to deal with than is deficient bone in the top part of the femur. For these reasons, I think that patients should be somewhat skeptical of articles that appear in the lay press regarding potential advantages of this surgical procedure that has been around for quite some time.
William P. Barrett, M.D.
WPB/mf
