I am asked, “Is hip resurfacing arthroplasty possible through the anterior approach.” The answer is yes and I believe that the anterior approach is the preferable way to perform this procedure. Hip resurfacing, also known as hip surface replacement is a procedure that is primarily advocated for younger patients. There is less removal of bone from the femur. The head of the femur is machined to a smaller size and a metal cap placed over it rather than completely removing the femoral head as is done with standard hip replacement. One of the main arguments supporting it is that taking less bone can be advantageous for the young patient if later revision of the femoral component is necessary which is more possible in young patients. What is typically not discussed by most surgeons is that preserving muscle attachments to the femur is also very important, particularly in young patients who may require revision surgery. Currently the large majority of hip resurfacings are performed through a large posterior approach that is more soft tissue invasive than anterior approach. Anterior approach hip resurfacing can preserve the femoral attachments of the hip musculature along with preservation of femoral bone stock.
The other important question is: Is hip resurfacing the best prosthesis choice for an individual patient? In general hip resurfacing is not recommended for older patients for whom there is a probability of living the rest of their life without the need for revision surgery. The answer as to whether hip resurfacing is the right choice for younger patients is also not clear. There is currently lack of conclusive evidence that patients function better after hip resurfacing than after standard hip replacement. Also, we do not have long term (20 year) follow-up studies that demonstrate the longevity of resurfacing. The current metal-metal surface replacement prostheses are more promising than past designs. Hip resurfacing prostheses have been available for over 30 years though past designs have been abandoned because of a high failure rate. The early results of the current designs however, show fewer failures and revisions at 5 to 10 years (1-5%) but still a somewhat higher revision rate than standard hip replacement.
The widely accepted advantage of hip resurfacing is that because of the bone preservation, revision of a failed femoral component is easier and more secure than after failure of a standard femoral component. The reservations regarding resurfacing are that the femoral component is probably more likely to need revision and that metal-metal is the only bearing surface available (see my blog comments on bearing surfaces).
Another disadvantage of hip resurfacing is that though less bone is taken from the femur it is almost always necessary to remove more bone from the acetabulum (hip socket) to place the resurfacing socket than would be removed with standard hip replacement. Therefore though hip resurfacing is more conservative on the femoral side it is more aggressive on the acetabular side.
Hip resurfacing is therefore another prosthesis option through anterior approach that has a high probability of an excellent functional result. Revision of a failed resurfacing arthroplasty to a standard hip replacement can also be performed through the anterior approach.
The use of current design metal on metal hip resurfacing prostheses is currently declining from a peak several years ago. I believe the reasons for this decline are concerns over metal on metal bearings and their complications as well as lack of definitive evidence of better function than traditional design hip replacement prostheses.
Joel Matta, MD