There is a lack of evidence for the safety of commonly-used implants in knee surgery, experts say today.
Professor Andrew Carr of Oxford University, UK, and colleagues publish an overview of the current situation on knee replacements in the Lancet.
They explain that the surgery is carried out frequently and is highly successful at relieving the pain of advanced arthritis of the knee, usually osteoarthritis, and improving knee function.
As replacement is increasingly given to patients younger than 55, the team say that "improved decision making about whether a patient should undergo the procedure is needed".
They looked at surgery outcomes from national registries, as well as patient-reported outcomes. "Widespread surveillance of existing implants is urgently needed", they warn, "alongside the carefully monitored introduction of new implant designs".
Dr Carr said: "The regulatory framework for new implants varies worldwide but has been generally much less rigorous than for new drugs. Currently, proof of safety of implanted materials is all that is required prior to approval for clinical use, rather than evidence for clinical effectiveness.
"Widespread surveillance of existing implants is urgently needed alongside the carefully monitored introduction of new implant designs as part of well conducted large-scale randomised trials."
He adds that: "Without high-quality, unbiased, and reliable information, surgeons cannot make informed decisions about how to achieve the best outcome in each clinical situation."
But he concludes: "Patients should be reassured that knee replacement surgery has proved to be one of the outstanding success stories of modern medicine and has resulted in significant quality of life gains for people with end stage arthritis."
* British hip specialists have called for controversial metal on metal implants to be abandoned.
The call came after the annual meeting of the British Hip Society last week.
The UK Medicines and Healthcare products Regulatory Agency has already ordered surgeons to increase supervision of patients who have had the implants – following allegations that they may leach dangerous metals into the body.
But a statement from the Hip Society said the implants – with bearings of 36 mm or more – should no longer be performed routinely unless more evidence is available.
Knee replacement. Carr, A. J. et al. The Lancet March 6 2012 doi:10.1016/S0140-6736(11)60752-6
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