Ten-year follow-up data from the FIDELITY study of arthroscopic partial meniscectomy (APM) in patients with symptoms of degenerative meniscal tear found the procedure offered no benefits and was even associated with worse outcomes.

The FIDELITY study used sham APM as the placebo control. The study involved 146 patients, aged 35-65 years, who were randomized during exploratory arthroscopy either to have damaged or loose parts of the meniscus removed, or to a sham procedure where the surgeon mimicked the movements of surgery without removing any tissue.

The 1-year data found no differences between the sham and real surgery groups in patient-evaluated functional outcomes, health-related quality of life, or knee pain after exercise.

Now the 10-year data, published as a correspondence letter in The New England Journal of Medicine, has found a sustained lack of benefit, with no significant differences seen between the sham and real surgical groups in any of the three primary outcomes.

Furthermore, among the 133 patients assessed at 10 years, 22% of those in the surgical group had progressed to clinical knee osteoarthritis compared with 19% of those in the sham surgical group, and 12% of those in the surgical group had undergone high tibial osteotomy or total knee replacement compared with 4% of those in the sham surgery group.

The rates of radiographically confirmed progression of osteoarthritis were also higher in the partial meniscectomy group than in the sham surgery group (81% vs 70%).

“This was an efficacy trial. We were trying to show that this procedure could work,” said orthopedic surgeon Teppo Järvinen, MD, PhD, of the University of Helsinki in Helsinki, Finland. “For the procedure to be considered viable, one would expect some indication or proof of benefit, not quite a consistent proof of harm.”

Järvinen said the finding of no benefit at 10 years supported the 5-year follow-up data, but the evidence pointing to harm was surprising. “Up until 5 years, our data [showed that there] was pretty much no benefit, so both the groups were equal, but then all of a sudden, the APM group starts to really crash,” he told Medscape Medical News. “This is the mechanistic proof that this is actually detrimental.”

Trial ‘Basically Confirms That There’s No Benefit of the Arthroscopy’

Commenting on the findings, rheumatologist Anita Wluka, MBBS, PhD, at Alfred Hospital and Monash University in Melbourne, Australia, said it was good to have more long-term follow-up data showing the same lack of benefit seen at 1 year. “It suggests that we probably shouldn’t be doing APM in the degenerative osteoarthritic knee with early osteoarthritis,” she said in an interview.

Wluka noted that the trial also represented the most ideal scenario for surgical intervention yet still did not show benefit. “These people being in a clinical trial were probably looked after beautifully, with kid gloves,” she said.

Rheumatologist and clinical epidemiologist Rachelle Buchbinder, MBBS, PhD, from Monash University, said the trend in this study was supported by other observational data suggesting those who have knee arthroscopy have knee replacements earlier than people who don’t, and this was particularly evident among older people.

“This is one of four placebo-controlled trials, and it’s the only one with 10-year data or 5-year data, and it basically confirms that there’s no benefit of the arthroscopy,” Buchbinder said.

While the theory underlying APM was that it was a way to clean out the joint “like sweeping the kitchen,” Buchbinder said, it may be instead that the debridement was disrupting the joint and accelerates the degeneration.

“We already know from people that have their menisci removed for acute injury, they all get premature osteoarthritis, so we know enough now to know that taking tissue away from the knee probably is harmful,” she said.

However, she stressed that the results did not apply to young people with an acute tear from the result of twisting their knee, or to people who were unable to move the knee because of meniscal damage. “If can’t move your knee because it’s stuck, then the only thing you can do is operate to release it,” she said.

The FIDELITY study was supported by the Sigrid Jusélius Foundation, the state funding for university-level health research, the Social Insurance Institution of Finland, and the Academy of Finland. One author declared receiving support from the Swedish Research Council, the Swedish Rheumatism Association, and another from the Finnish Medical Foundation and the Orion-Farmos Research Foundation. Järvinen, Buchbinder, and Wluka reported having no relevant financial disclosures.