Males, Younger Patients at Higher Risk for Multiple Revisions After Knee Replacement

By Lisa Rapaport

May 21, 2021

(Reuters Health) - Patients who undergo knee replacement surgery may have a higher risk for multiple revision procedures when they're male or less than 55 years old, a recent study suggests.

Researchers examined data from the UK 2019 National Joint Registry on 1.19 million primary knee replacements as well as 75,881 revision knee replacements recorded in this registry from April 1, 2003, to December 31, 2018. They identified 33,292 revisions that could be linked to one of the primary knee replacements in the registry and focused the analysis on these procedures.

Overall, 3,575 (10.7%) of the revisions in the analysis were revised a second time, and 574 (1.7%) required a third revision.

Within 13 years of the first revision, 19.9% of the cases resulted in a second revision. Within five years of the second revision, 20.7% of cases resulted in a third revision. And within three years of the third revision, 20.7% of cases resulted in a fourth revision.

Ten years after the primary knee replacement, revision rates were significantly higher in males than females (20.0% vs 14.8%), the analysis found. At ten years, men younger than 55 years were significantly more likely to have revisions than men 75-79 years old (26.6% vs 13.6%), a trend that was also seen for women in the same age ranges (21.0% vs 8.3%).

"The greatest contributing factor is most likely to be greater activity levels leading to accelerated wear and loosening, although men are also more likely to have infections leading to revision surgery," said senior study author Ashley Blom, a professor of orthopedic surgery and head of Bristol Medical School at the University of Bristol in the UK.

Revision usually does improve pain and function, but not as effectively as primary joint replacement, Blom said by email. Patients undergoing revision surgery are more likely to have no functional improvement or functional deterioration than those undergoing primary knee replacement, Blom added.

"The likelihood of improvement in pain and function needs to be balanced against the risks outlined above and patients should consider the risks and benefits before deciding on whether to have surgery," Blom said.

Most often, the first revision in the analysis was done due to aseptic loosening or lysis (27.1%), infection (19.0%), or pain (16.4%), researchers report in The Lancet Rheumatology.

One limitation of the study is that researchers assessed all types of primary knee replacements in a single group. The analysis also did not examine differences in outcomes based on the specific replacement knee, fixations or constraints that were used in the initial operation.

Multiple authors on the study reported financial ties to medical device companies including Zimmer and Stryker.

Another drawback is that the study doesn't account for differences by surgeon, said Dr. Marty Makary, a professor of surgery and public health at Johns Hopkins University in Baltimore who wasn't involved in the study. There is often variation in surgical quality, and the risk of revision should be lower in a subgroup of highly skilled surgeons, Dr. Makary said by email.

"The main finding here is that a knee replacement may result in the need for a second knee replacement in 20% of patients, and a person who has a second may even need a third," Dr. Makary said. "These risks should be clear to patients who undergo the operation."

SOURCE: and The Lancet Rheumatology, online April 29, 2021.