Limiting hip resurfacing to appropriate patient population will aid in success

ORLANDO, Fla. — Despite the problems seen with some hip resurfacing implants, hip resurfacing is still a viable alternative to hip replacement in appropriately selected patients, a surgeon here said.

“Many of the reasons not to perform hip resurfacing are based upon fear: fear of fracture, fear of difficulty of the technique, fear of metal reactivity and sensitivity. I implore you that we should not allow fear to triumph over reason,” Edwin P. Su, MD, said during a presentation at the 2010 Current Concepts in Joint Replacement Winter Meeting.

In support of hip resurfacing

Su presented several factors in favor of hip resurfacing. Hip resurfacing preserves bone, as was observed in a cadaveric study he and his colleagues performed that compared hip resurfacing and hip replacement to determine the extent of bone loss.

He also pointed out that not all implants are created equally and referred to the high rates of early failure that were seen with the Durom (Zimmer) and the ASR (DePuy) hip resurfacing systems.

“My point to you is that these two implants had design flaws that led to problems, and they are not representative of all resurfacing implants. So we should not throw the baby out with the bathwater,” Su said.

He went on to explain that most problems with hip resurfacing can be avoided by good surgical technique coupled with a good implant, noting that hard-on-hard bearings are more sensitive to malpositioning, which could result in edge-loading. With a metal-on-metal (MoM) bearing, edge-loading will lead to metal ion debris and possibly metal reactivity.

Patient selection

In addition to the quality of surgical technique and implant, Su stated that patient selection is especially important when considering MoM hip resurfacing. He referred to intermediate data from the Australian National Joint Registry to further make his point: Hip resurfacing implants in women are failing at about twice the rate of those in men, and revision rates were similar among men under the age of 55 who underwent hip resurfacing compared with those who underwent total hip arthroplasty.

This data can be used to guide the selection of patients who will have the greatest success with resurfacing, Su said.

“Patient selection is extremely important, and the Australian registry is showing us that it should be performed in men under the age of 55 with osteoarthritis and a large head size,” he said.

References:

• Australian National Joint Registry.
• Cross MB. Acetabular bone removal in hip resurfacing arthroplasty vs. total hip arthroplasty: a comparison using the acetabular cup to native femoral head diameter ratio. Paper #29. Presented at the 2010 Meeting of the European Hip Society. Sept. 9-11, 2010. Athens.
• Su EP. Comparison of bone removed during total hip arthroplasty with a resurfacing or conventional femoral component: a cadaveric study. J Arthroplasty. 2010;25(2):325-329.
• Su EP. Metal-metal surface replacement: a triumph of hope over reason – opposes. Paper #3. Presented at the Current Concepts in Joint Replacement 2010 Winter Meeting. December 8-11, 2010. Orlando.

After that debate, Dr. Rob Barrack at Wash University presented some data that may conclusively prove that hip resurfacing patients have a better functional outcome than total hip replacement patients.  It has been debated over and over whether or not there are any differences in the results of THR vs. resurfacing...his study showed that there are superior outcomes with regard to function.  Also Dr. Su pointed out to me that they misquoted him, he said men under the age of 65, not 55.

Dr. Edwin Su and Dr. John Cuckler, a very well-respected surgeon, about the merits of hip resurfacing, so I used this video to break the ice, as my ideal “virtual debate”