At a glance: what the 10-year evidence means
A 10-year sham-controlled trial found no long-term benefit from trimming a degenerative meniscus tear with keyhole surgery in middle-aged and older adults without established arthritis. That does not mean every tear should avoid arthroscopy. Some tears still need it, and some can be repaired.
What was the FIDELITY study, and who does it apply to?
FIDELITY compared trimming a degenerative tear with sham surgery, in middle-aged and older adults with minimal or no X-ray osteoarthritis. The findings apply to that group first.
FIDELITY is a carefully designed trial. It applies to one specific group of people.
The trial tested arthroscopic partial meniscectomy against sham surgery. Partial meniscectomy is a keyhole operation that trims away the torn part of the meniscus. Sham surgery is a pretend operation. It lets researchers separate the effect of the operation itself from the effect of simply having had surgery [#1].
Everyone first had a diagnostic arthroscopy, a look inside the knee with a small camera, to confirm they were eligible. During the same procedure, they were then assigned by chance to have the tear trimmed or to have sham surgery. Neither the participants nor the people assessing the results knew which group each person was in [#1].
In total, 146 people were randomised. About 91 percent of each group were followed up at 10 years: 64 of 70 in the meniscectomy group and 69 of 76 in the sham group [#1].
Who took part? Adults with a degenerative tear in the medial meniscus, the cushion on the inner side of the knee. They had minimal or no established osteoarthritis on X-ray [#1]. Osteoarthritis is the gradual wear of a joint, where the smooth cartilage thins over time. The study team described the participants as middle-aged and older adults. The published letter does not give a fixed age band [#1].
It is strong evidence for a defined group, not for every knee.
How is a degenerative tear different from a traumatic tear?
A degenerative tear builds with wear and a traumatic tear follows an injury. FIDELITY studied the first, so its results should not be applied automatically to the second.
The word “tear” covers two quite different situations. The 10-year result is about only one of them.
A traumatic tear usually follows a specific injury, such as a twist during sport. A degenerative tear develops gradually, as the meniscus tissue wears with age and use.
FIDELITY studied degenerative tears. Traumatic tears were not what the trial tested [#1].
For a closer look at how tears are classified and assessed, see our guide to meniscus repair surgery.
What did the 10-year results show?
At 10 years there was no benefit from meniscectomy on the measures reported, and one knee score was clearly worse. Some gaps could be chance, and the trial shows association, not proof of cause.
At 10 years, trimming did not show a benefit over sham surgery on the measures reported. One measure leaned the other way.
The main findings below come from the 2026 New England Journal of Medicine letter [#1].
Arthritis on X-ray. Osteoarthritis progression on X-ray was seen in 81 percent of the meniscectomy group and 70 percent of the sham group. The letter adds a caution. The statistical range around that gap included no difference at all. So the figures point in one direction, but they do not prove the gap is real.
Knee replacement or bone-shaping surgery. Eight people (12 percent) in the meniscectomy group had a knee replacement or a high tibial osteotomy, a bone-shaping procedure. In the sham group, three people (4 percent) did.
How the knee felt and worked. The letter reported no 10-year benefit of meniscectomy on the measures it reported. One patient-reported knee score, which asks about symptoms and function, was lower after meniscectomy, by a margin unlikely to be chance. Lower here means worse.
| Measure at 10 years | Meniscectomy group | Sham surgery group |
|---|---|---|
| Osteoarthritis progression on X-ray | 81 percent | 70 percent |
| Knee replacement or high tibial osteotomy | Eight people (12 percent) | Three people (4 percent) |
The statistical range around that gap included no difference at all [#1].
The authors concluded that, even in a group chosen to give surgery the best chance of showing benefit, they found no evidence of benefit and a suggestion of worse outcomes. They said these findings, taken together with other evidence, raise concern about using partial meniscectomy for degenerative tears in middle-aged and older adults [#1]. Earlier trial results and reviews of the wider evidence are consistent with this [#4][#5].
A note on cause. The trial compared two groups. It shows differences between those groups. It does not by itself prove that trimming caused the extra arthritis. A fuller account of long-term joint health is in the meniscus repair surgery guide.
What does the study not mean?
The trial does not mean every tear should avoid arthroscopy, and it is not a prediction for any single knee. It questions routine trimming of degenerative tears.
The result is a reason to question unnecessary trimming. It is not a reason to rule out arthroscopy.
The trial studied degenerative tears. It does not mean every meniscus tear should be managed without arthroscopy. Traumatic tears, displaced fragments, a knee that locks or catches, and tears that can be repaired are different problems, and the trial did not test them [#1].
Exercise and physiotherapy are a common first step for a degenerative tear, in line with the wider evidence on arthroscopic surgery for degenerative knee problems [#4][#5].
When does knee arthroscopy still have a role?
Arthroscopy can still have a role when a knee locks, a fragment is displaced, or a tear can be repaired. The decision rests on your symptoms and examination, not the scan alone.
Some meniscus problems are mechanical. For those, keyhole knee arthroscopy may still have a place.
Arthroscopy can remain a reasonable option in a few situations:
- A knee that truly locks or catches.
- A displaced fragment that blocks movement.
- A tear that can be repaired rather than trimmed.
A locked knee is different from ordinary stiffness. If a knee is stuck and will not straighten, arrange an assessment promptly. The urgent-signs list at the end of this page explains when.
The question is not only “is there a tear?” It is whether this tear is causing the problem, and which operation, if any, fits it.
Repair or trim: which keeps more of the meniscus?
Repair keeps the meniscus but needs the right tear and carries a higher chance of a further operation. The evidence for repair in older adults is real but weaker than the evidence against unnecessary trimming.
Where a tear is suitable, repair keeps the meniscus. Trimming removes part of it. Each has trade-offs.
The meniscus spreads load through the knee [#3]. Keeping tissue where it is reasonable to do so is the idea behind repair. Our guide to meniscus repair surgery explains both operations in detail.
| Repair | Partial meniscectomy (trim) | |
|---|---|---|
| What it does | Stitches the torn tissue back together and keeps the meniscus | Removes the torn or unstable fragment |
| Chance of a further operation | Higher than with trimming [#6] | Lower than with repair [#6] |
| Evidence for degenerative tears | Weaker: mostly retrospective case series [#2] | Stronger: a sham-controlled trial found no long-term benefit [#1] |
What about older patients? A review of 14 studies of meniscus repair in people aged 40 and over found that repair can work in carefully selected patients. [2] Failure was 12 percent (95% confidence interval 7.3 to 19.4 percent), and a repeat meniscus procedure was needed in 9.8 percent [#2]. The authors concluded that age alone should not decide whether a repair is attempted [#2].
There are limits. The review is level 4 evidence, drawn mostly from retrospective case series. [2] Horizontal or complex tears failed more often than vertical ones: 41.7 percent compared with 15.6 percent [#2]. The review does not show that repair prevents arthritis. These failure rates also cannot be applied to one person, because the range is wide and studies defined failure differently.
This is why the evidence for repair is weaker than the evidence against unnecessary trimming. The aim is neither to operate on every tear nor to stop operating. It is to work out who is likely to benefit and to keep as much meniscus as possible.
What questions should I ask at my consultation?
If you are weighing knee arthroscopy for a meniscus tear in Singapore, these questions can help you and your doctor think it through. They are prompts for discussion, not a checklist of right answers.
- Is my tear degenerative or traumatic, and how do you know?
- Which of my symptoms do you think the tear explains?
- Do I have mechanical symptoms, such as true locking or a fragment that blocks movement?
- Have I had a fair trial of exercise and physiotherapy?
- What does my X-ray show about osteoarthritis?
- Could my tear be repaired, and what would that recovery involve?
- What are the risks and uncertainties of each option, including waiting?
For broader assessment and the other conditions we cover, see our knee care overview.
Frequently asked questions
What did the FIDELITY 10-year study find about partial meniscectomy?
At 10 years, trimming a degenerative medial meniscus tear showed no benefit over sham surgery on the measures reported. X-ray osteoarthritis progression was seen in 81 percent versus 70 percent, though that gap’s statistical range included no difference. One patient-reported knee score was clearly worse after meniscectomy [#1].
Do I need knee arthroscopy for a degenerative meniscus tear?
Not necessarily. For degenerative tears, exercise and physiotherapy are a common first step, and the wider evidence on arthroscopy for this kind of knee problem is not favourable [#4][#5]. Arthroscopy is more likely to be considered if the knee truly locks or a fragment blocks movement. Your assessment decides.
Is a degenerative meniscus tear different from a traumatic tear?
Yes. A degenerative tear develops gradually with wear, often in middle-aged and older knees. A traumatic tear follows a specific injury. They behave differently and are managed differently. FIDELITY studied degenerative tears, so its results should not be applied automatically to traumatic ones [#1].
When does knee arthroscopy still help a meniscus tear?
It may help when a knee truly locks or catches, when a displaced fragment blocks movement, or when a tear is suitable for repair. In these cases the tear is causing a mechanical problem. A degenerative tear without those features is a different situation, as FIDELITY suggests [#1].
Meniscus repair or trimming: which keeps more of the meniscus?
Repair keeps the meniscus, while trimming removes the torn part. Repair carries a higher chance of a further operation [#6]. Whether a tear can be repaired depends on its location, pattern and tissue quality, and is assessed individually. The evidence for repair in older adults is weaker [#2].
Can trimming a degenerative meniscus tear lead to osteoarthritis?
Trimming removes meniscus tissue. In FIDELITY, more of the meniscectomy group showed X-ray osteoarthritis progression at 10 years (81 percent versus 70 percent). That gap’s statistical range included no difference, and a trial shows an association between groups, not proof that trimming caused it [#1].
What should I ask my surgeon before agreeing to meniscus surgery?
Ask whether your tear is degenerative or traumatic, which symptoms it explains, whether you have true locking, and whether exercise-based care has had a fair trial. Ask whether repair is possible, and what the risks of each option are. The list of questions above can help you prepare.
References
- Kalske R, Sihvonen R, Paavola M, et al. Arthroscopic Partial Meniscectomy for Degenerative Tear — 10-Year Outcomes. N Engl J Med. 2026;394(17):1757–1759. doi:10.1056/NEJMc2516079. PMID 42054686. (FIDELITY — 10-year)
- Sedgwick MJ, Saunders C, Getgood AMJ. Systematic Review and Meta-analysis of Clinical Outcomes Following Meniscus Repair in Patients 40 Years and Older. Orthop J Sports Med. 2024;12(8):23259671241258974. doi:10.1177/23259671241258974. PMID 39131093. PMC11311169.
- Fox AJS, Wanivenhaus F, Burge AJ, Warren RF, Rodeo SA. The human meniscus: a review of anatomy, function, injury, and advances in treatment. Clin Anat. 2015;28(2):269–287. doi:10.1002/ca.22456. PMID 25125315.
- Sihvonen R, Paavola M, Malmivaara A, et al. Arthroscopic partial meniscectomy versus sham surgery for a degenerative meniscal tear. N Engl J Med. 2013;369(26):2515–2524. doi:10.1056/NEJMoa1305189. PMID 24369076. ClinicalTrials.gov NCT00549172. (FIDELITY trial — primary)
- O’Connor D, Johnston RV, Brignardello-Petersen R, et al. Arthroscopic surgery for degenerative knee disease (osteoarthritis including degenerative meniscal tears). Cochrane Database Syst Rev. 2022;3:CD014328. PMID 35238404.
- Boric-Persson F, Turkiewicz A, Englund M, Neuman P. Increased reoperation rates after meniscus repair compared to arthroscopic partial meniscectomy: Data from a comprehensive clinical cohort with up to 10 years follow-up. Knee Surg Sports Traumatol Arthrosc. 2026;34(6):1946–1959. doi:10.1002/ksa.12791. PMID 40686041. PMC13266913.
Final next step
Reading about a problem is a starting point. An assessment brings together the history, an examination where needed and any useful tests, and helps you and your clinician decide what to do next. How much physical examination is needed is a matter of clinical judgement. It may be limited when pain makes an examination unreliable, or when imaging clearly shows a problem that matches the symptoms, such as a fracture seen on an X-ray or an MRI scan that clearly shows an injury consistent with the symptoms. The Singapore Medical Council and the UK General Medical Council both allow remote medical consultations, where a physical examination is not possible, with safeguards: the doctor must be clear about the limits of an opinion formed without an examination, and whether an in-person examination is needed, or referral to other services, is left to the clinical judgement of the attending doctor.
If this raised questions about your own situation, an assessment can help organise them.
OrthoKinetics does not provide emergency or urgent care through this webpage or its WhatsApp contact.
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