Dr. Dave Dalury and coauthors presented a study of 872 consecutive knee revisions performed at 3 centers around the United States. This paper was presented the 22nd annual meeting of the American Association of Hip and Knee Surgeons. They found that the indications for revisions have changed compared to a decade ago. Previously there were a significant number of revisions performed for wear of the polyethylene and changes in the bone as a result of these wear products. The most common cause of revision surgery was infection in 21.8% of cases, loosening of the implants in 21.5 %, polyethylene wear in 16%, and instability in 16%. This change in incidence of various causes of revision reflects improved materials being used in knee replacement over the last 5 years and improved surgical techniques that have decreased the incidence of instability. While the majority of patients do well following knee replacement, there are still causes of failure both early and late. The early failures (within 2 years) tend to be related to mechanical problems associated either with the operation or the implant, whereas longer term failures tend to be the result of wear and loosening.
—William P. Barrett, MD