FIDELITY

Why was this trial needed?

Meniscal damage seen in MRI is a common finding in middle-aged and older individuals with knee pain. For years, conventional wisdom held that these degenerative meniscal tears were the primary cause of symptoms, fueling the widespread use of arthroscopic partial meniscectomy (APM). However, this practice lacked solid evidence of benefit. A series of randomized controlled trials, including FIDELITY, demonstrated that APM provides minimal or no improvement in symptoms compared to placebo surgery. Concerns remain that APM may even accelerate the development of knee osteoarthritis (OA).

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What is the primary objective of the FIDELITY trial?

The original FIDELITY trial showed that APM was no better than placebo surgery in relieving knee pain and other symptoms over the short term (1- and 2-year follow-ups). The extended 5- and 10-year FIDELITY-OA follow-ups aim to determine the long-term effects of APM on knee symptoms and the development and progression of knee OA.

‍Where are we now?

We have already published the following articles:

• Protocol article in the BMJ Open
• 1-year results in the New England Journal of Medicine
• Effect on mechanical symptoms in Annals of Internal Medicine.
• 2-year results in the Annals of the Rheumatic Diseases
• 5-year results in the British Journal of Sports Medicine
• Cost-effectiveness analysis in Clinical Orthopaedics and Related Research
• 5-year MRI findings in Osteoarthritis and Cartilage

We have completed the final 10-year follow-ups and as of July 2025, we are finalizing the first manuscript reporting the 10-year results. The final chapter of FIDELITY is just around the corner – exciting times ahead!

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Project team

Mika Paavola – Antti Malmivaara – Simo Taimela – Roope Kalske

Contributors

Ari Itälä – Antti Joukainen – Heikki Nurmi – Juha Kalske – Martin Englund – Anna Ikonen – Timo Järvelä – Tero Järvinen – Kari Kanto – Janne Karhunen – Jani Knifsund – Heikki Kröger – Jaanika Kumm – Tommi Kääriäinen – Janne Lehtinen – Jukka Nyrhinen – Juha Paloneva – Outi Päiväniemi – Marko Raivio – Janne Sahlman – Roope Sarvilinna – Niko Sillanpää – Aleksandra Turkiewicz – Sikri Tukiainen – Ville-Valtteri Välimäki – Ville Äärimaa

Clinical research coordinators:

Ina Fagerlund – Saara-Maija Hinkkanen – Elina Jalava – Sari Karesvuori – Pekka Karppi – Johanna Koivistoinen – Kirsi Saarioja – Marja-Liisa Sutinen – Marketta Rautanen – Mari Routapohja

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