The Hype of Hip Resurfacing: What They Did Not Say

The Hype of Hip Resurfacing: What They Did Not Say

There are numerous articles in newspapers and internet sites produced by various marketing departments promoting the recently released "Resurfacing Hip Replacement" procedure. It is typically not explained that this is an extremely controversial concept within orthopaedic circles. The procedure has been around for over twenty years. The design is currently in its third generation, and continues to have a failure rate that is higher than a standard hip replacement. It is true that well intentioned and well trained surgeons may be doing this procedure. However, this procedure is looked upon with skepticism by the majority of the orthopaedic community.

Promotional Terminology

Claim:

  • Allows greater range of motion and has a lower dislocation risk compared to "traditional hip replacement".
Response:
  • Comparing hip resurfacing to "a traditional hip replacement" is a false comparison. The vast majority of surgeons experienced in total hip replacement would use more modern technology in a young person with higher activity demands and desires. This would also be of a metal on metal design with larger femoral head sizes essentially providing the same range of motion and dislocation risk as that of a resurfacing procedure.

Claim:

  • Wear is better than "traditional total hip replacement".
Response:
  • Metal bearing surfaces as well as ceramic and newer processing methods for plastic all wear better than the "old style total hip replacement". Metal on metal ball and socket bearings with the same technology as in the "Resurfacing" procedure are available to be applied to the standard bone ingrowth hip stems, allowing the same advantages as the resurfacing procedure without increasing the failure risk.

Claim:

  • Allows greater activity level or shorter rehabilitation time compared to "standard hip replacement".
Response:
  • Given that the resurfacing procedure is done only in young patients, of course they will have higher activity levels, and quicker recovery than the typical patient who is several decades older getting the "standard hip replacement". There is no controlled study done with comparable age and disease groups that would support their claim.

Claim:

  • The resurfacing procedure is more "bone saving".
Response:
  • This is true. But the actual soft bone, marrow, and few centimeters of femoral neck of upper femur are inconsequential to the long-term function of the hip replacement, especially when considering the higher failure rate of the resurfacing procedure due to its inferior fixation mechanics. The fixation of the typical total hip replacement stem is secured in the upper bone of the thigh with bone ingrowth leading to a reliability of fixation of 98 % to 99 % over fifteen years. The metal cap on the head of the femur in a resurfacing procedure is secured with cement and a short peg in soft bone. Cement on a femoral stem has long fallen out of favor for the higher activity demand patient, and does not hold up as well as bone ingrowth does over time.

Claim:

  • Resurfacing allows more options if later surgery is required.
Response:
  • There is no study that compares the results of revision surgery of resurfacing procedures to those of regular hip replacement. To suggest that "more options" would imply better results is not proven in any study. It is true that more area of bone is still present, however, its quality and function have debatable significance. Studies show that the failure rate of resurfacing is higher and you are more likely to need another procedure.

Claim:

  • The resurfacing transmits more physiologic loads to the upper femur.
Response:
  • This is true, but the load transfer when compared to a standard femoral stem with bone ingrowth has never been a problem or led to failure. Although less "normal" in it stress transmission, it is far more reliable and durable with no proven detriment, thus making the higher failure rate of resurfacing not worth the risk in the opinion of many, if not most, orthopaedic surgeons.

Pitfalls:

  • The resurfacing hip procedure has very strict selection criteria. As stated by Dr. Mont at the annual orthopaedic meeting, these patients must be "carefully selected in order to reduce the incidence of complications". Also from Dr. Lachiewicz's presentation at the meeting, there are actually "very limited number of patients for whom hip resurfacing is truly indicated". The anatomy of the femoral neck is critical for the success and is the most likely source of failure. The inducement to relaxing these strict criterion to accommodate patient demands will likely increase the failure rate even further.
  • Several studies have shown this procedure has a very steep learning curve. Often fifty to one-hundred cases are required in this more difficult procedure before consistently best results are achieved. Dr. Vail at the annual meeting indicated that "technical factors play a larger role and lead to a higher failure rate".
  • The incision is usually larger than small incision total hip replacement surgery.
  • Very limited ability to adjust leg lengths and unable to correct deformity at the hip.

Even in the best selected patients the results are still inferior to standard hip replacement. Dr. Vail "the procedure lacks a long-term track record" and Dr. Lachiewicz "the risk and complications of hip resurfacing outweigh any possible advantages.

The recent trend of direct to patient medical marketing without the overview of all view points is not in the best interest of our patient population.

John G. Mayer, M.D.
Private Practice Lake County Illinois
Member American Board of Orthopaedic Surgery
Member American Association of Hip and Knee Surgery

-JGM