What’s new in hip resurfacing?
Hip resurfacing has continued to gain traction as an alternative to hip replacement for arthritis. New information continues to come out.
Surgeon Experience
A panel discussion was held at the 3rd Annual Hip Resurfacing Forum in September 2006. The consensus was that experience was a major factor in the success of the procedure. The results are not nearly as favorable in a surgeon’s first 30 to 50 cases. The best statistical results start to appear after 300 procedures. Because hip resurfacing is much different that hip replacement general familiarity with hip surgery is not a substitute for direct experience with the resurfacing procedure.
The learning curve is steep in acquiring the necessary skills which include patient selection, safe exposure, and component positioning and complication management. The incidence of femoral neck fracture, nerve injury, and component positioning difficulties are higher in a surgeon’s earlier cases.
Materials
Metal-on-Metal has proven to be the most successful bearing material for hip resurfacing. All the available prostheses now use an alloy of cobalt-chromium. The metallurgy is intellectual property of the different vendors. If appears at this time that all vendors are offering high quality metals and that wear is not a problem. We have only seen one patient with a local reaction to the metal in 400 procedures. There have been no known health consequences from the metal to date.
I still dream of using a softer material. We are working with polymer chemists and maybe someday a new polymer will also be an option. This will not be a return to polyethylene as the wear debris from polyethylene was a problem when we used it in the past. Some surgeons mistake the current generation of resurfacing prostheses with the older polyethylene implants from many years ago.
Long Term Followup
In April 2007, I presented at a major medical meeting our 20 year results with predecessor to the current resurfacing prostheses. The femoral components worked well and when a metal socket was used the results were favorable.
Harlan Amstutz MD from Los Angeles followed my presentation with the ten follow-up of 1000 Conserve Plus Resurfacing procedures. His report was very favorable.
The McMinn Center in England now reports a 98% success rate at 15 years with the Birmingham Hip Resurfacing.