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Study: UKR use can be safely expanded to reduce its revision rate
By opening up the procedure to more patients, researchers believe the revision rate for unicompartmental knee replacement may decrease.
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NEW ORLEANS — Despite a long-standing belief that limiting the eligible number of patients for unicompartmental knee replacement reduces revision rates for the surgery, a presenter at the American Academy of Orthopaedic Surgeons Annual Meeting said this practice may have led to increased revision rates for unicompartmental knee replacement surgery.
Alexander D. Liddle, MBBS, and colleagues found that limiting individuals who are selected for this procedure to a few “ideal” patients — generally patients who are younger and fitter — can drastically alter revision rates with unicompartmental knee replacement (UKR).
“There have now been several studies which together have formed a strong narrative that surgeons who perform more UKRs each year achieve the best results,” he said.
“What this study has shown is that increasing usage (by broadening the indications for UKR) is a safe and viable method for surgeons who want to increase the numbers of UKRs they perform,” Liddle said.
Less does not always equal more
In the study abstract, Liddle and colleagues noted UKR offers advantages over total knee replacement, such as lower morbidity and mortality, faster recovery rate, and has lower costs. However, they said the procedure has a higher revision rate.
According to Liddle and colleagues, in the past when only the most “ideal” patients were selected for UKR surgery, this resulted in 5% of all patients presenting for knee replacement being deemed eligible for a UKR. However, in high volume UKR centers, as many as 50% can be considered eligible, and such centers have reported good long-term results. Therefore, they aimed in this investigation to determine the optimal UKR usage to minimize the high revision rates associated with UKR surgery.
The investigators reviewed data for more than 14,000 patients who had undergone UKR surgery as recorded in the National Joint Registry for England, Wales and Northern Ireland.
Liddle and colleagues explained in the study the lowest revision rates were in patients operated on by surgeons who use UKR in between 40% and 60% of knee replacement surgeries. However, they caution that those with very high usage figures (above about 50%) may represent tertiary referral practices and their success may not be generalizable to the wider population of knee surgeons.
“The risk of revision is greatest with the smallest usage: below 20%, the revision rate increased markedly. With optimal usage, and with the use of an implant designed for broad indications, the 5-year implant survival rate is 95.6% (99% CI; 94.5-96.5), compared with 90.1% (87.9-91.9) using low usage levels that have been previously considered to be ideal,” Liddle and colleagues wrote in the study.
Expanded use leads to fewer revisions
Liddle and colleagues concluded that opening up the indications for UKR would improve revision rates for the procedure. They noted that any disadvantage to operating on less “ideal” patients would be outweighed by the benefits associated with performing more UKRs per year. Surgeons who used narrow indications for UKR operated on patients who were generally younger and fitter patients and those patients are less likely to do well with such treatment, according to the investigators.
“The widespread use of broad indications, associated with appropriate implants, would give patients all the advantages of UKR, without the high reported revision rate,” Liddle and colleagues wrote. – by Robert Linnehan
- Reference:
- Liddle AD. Paper #181. Presented at: American Academy of Orthopaedic Surgeons Annual Meeting; March 11-15, 2014; New Orleans.
- For more information:
- Alexander D. Liddle, MBBS, can be reached at Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences, University of Oxford, Botnar Research Centre, Windmill Road, OX3 7LD, United Kingdom; email: alexander.liddle@ndorms.ox.ac.uk.
Disclosure: Liddle has no relevant financial disclosures.