Old Implants Have Edge On New (Biloine Young @ OTW)
It is back to the drawing board for new hip and knee prosthesis.
Reason? A five-year Australian study has found that the newer hip and knee replacement joints are performing no better—and sometimes worse—than the older, less expensive devices. The study concluded that 30 % of the new joints were performing worse than were the older versions.
The researchers obtained their data from a comprehensive Australian national registry database and performed an outcome analysis on all new hip and knee prostheses introduced into the market between January 1, 2003, and December 31, 2007. The prosthesis had to have been used on at least 100 occasions.
They then compared their findings with the combined results of the three best performing established hip and knee prostheses with a minimum duration of five years of follow-up. The principal outcome measures were the rate of revision per observed component years and the time to first revision, using the Kaplan-Meier estimate of implant survivorship.
Most of the prostheses introduced into the market during the study period were used on fewer than 100 occasions. An analysis of those that had been used more than 100 times showed that 27% (9 of 33) of the hip replacements and 29% (8 of 28) of the knee replacements had a significantly higher rate of revision than the older, established prostheses. None of the newer prostheses had a lower rate of revision than the established prostheses.
The researchers found that although 70% of the newer devices performed as well as the older versions, 30% of the newer hip implants and 29% of newer knee joints did worse—which then required the patients to have repeat surgery.
The Australian investigators concluded that the new devices were not only potentially hazardous to patients, but also contributed to increased health care costs. They wrote that some new artificial hip and knee joints are being introduced with “limited or no clinical evidence to justify their use,” making it difficult for surgeons to compare the performance of new implants against established devices with longer track records.
In the United States 700,000 patients—a number that is expected to go up as the population ages—undergo hip or knee replacements annually. The study was published in the December issue of Journal of Bone and Joint Surgery, Volume 93, Issue Supplement 3.