Meniscus Tears: Degenerative vs. Traumatic, and What That Changes

"They found a meniscus tear on my MRI" is one of the more common reasons people end up in a chiropractic or sports medicine office, often with a referral toward arthroscopy already on the table. What rarely gets explained — and what changes the conversation almost completely — is which kind of meniscus tear was found. The answer matters enough that two patients with apparently similar imaging can have very different best treatment plans.

Two fundamentally different injuries

Traumatic meniscus tears typically happen during a recognizable mechanism — a planted-foot rotation in soccer, a deep squat under load, a sudden cutting motion. They're more common in younger athletes, often involve a clear timeline (the patient remembers the event), and are sometimes associated with concurrent ligament injuries. Mechanically, they're tears in tissue that was structurally normal until the injury.

Degenerative meniscus tears are different. They occur in tissue that's been gradually changing for years — a tissue-level continuation of the same processes that produce knee osteoarthritis. They tend to occur in adults over 40, often without a recognizable mechanism, and they show up frequently on MRI in people who have no knee pain at all. In one well-known study, more than 60% of asymptomatic adults aged 50–90 had meniscal pathology on MRI¹.

The two injuries look similar in an imaging report, but they're not the same condition.

What the surgical evidence actually shows

The evidence on arthroscopic partial meniscectomy for degenerative meniscus tears is, at this point, hard to argue with. The FIDELITY trial — a sham-controlled randomized trial published in the New England Journal of Medicine — compared arthroscopy to a sham procedure in patients with degenerative medial meniscal tears and no knee osteoarthritis. The two groups had essentially identical outcomes at 12 months². A subsequent five-year follow-up found the same thing³.

Multiple other randomized trials and meta-analyses have come to similar conclusions. A 2017 BMJ Rapid Recommendation, after reviewing the literature, made a strong recommendation against arthroscopy for degenerative knee disease, including for symptomatic meniscal tears⁴. The clinical guideline change was significant — and slow to filter into practice.

For traumatic meniscus tears in younger patients, particularly bucket-handle tears producing mechanical symptoms (locking, true catching), the evidence still supports arthroscopy in selected cases. The selection matters; "mechanical symptoms" needs to be a specific clinical picture, not a vague description.

What rehab does for degenerative tears

Kise and colleagues compared a 12-week supervised exercise program to arthroscopic partial meniscectomy in patients with degenerative medial meniscus tears. Both groups improved meaningfully; there was no clinically significant difference between the surgery group and the exercise group at two-year follow-up⁵. The exercise group had less surgical risk, lower cost, and fewer post-operative complications, by definition.

That's not an indictment of orthopedic surgery. It's an indictment of arthroscopy as a default treatment for a specific subset of cases — the degenerative tear in an older adult without clear mechanical symptoms.

The exercise programs that work, in these trials and in our own clinic, are not gentle stretching. They're structured, progressive resistance work — quad strengthening, hip strengthening, single-leg stability — typically two to three sessions a week for 8–12 weeks. The same kind of work we wrote about in our piece on patellofemoral pain and IT band syndrome, applied to a different driving pathology.

How to tell which kind of tear you have

The history does most of the work. A specific mechanism, a younger patient, true mechanical symptoms (the knee locks at a specific angle, then has to be physically un-locked), a positive McMurray's, joint-line tenderness — these point toward a traumatic tear that may benefit from surgical evaluation.

An older patient with insidious-onset knee pain, no clear mechanism, generalized rather than locking discomfort, and an MRI that includes degenerative changes throughout the joint — that's the picture where exercise and load management are the first-line plan, with surgical opinion held in reserve for non-responders.

What we do at Boreal

For most adults coming in with knee pain and a recently identified meniscus tear, the first conversation isn't about surgery. It's about the difference between the two kinds of tears and what's most likely driving their specific picture. We coordinate with their referring physician, run a careful exam, and start with the rehab work the evidence supports for their presentation.

For some patients, that's enough. For others, a surgical opinion remains appropriate, and we say so. There are no bad treatment options — only mismatched ones, and matching the treatment to the actual injury is most of the job. That's the same logic we apply to knee osteoarthritis, and it applies cleanly here.

References

1. Englund M, Guermazi A, Gale D, et al. Incidental meniscal findings on knee MRI in middle-aged and elderly persons. N Engl J Med. 2008;359(11):1108–1115.
2. 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.
3. Sihvonen R, Paavola M, Malmivaara A, et al. Arthroscopic partial meniscectomy versus placebo surgery for a degenerative meniscus tear: a 2-year follow-up of the randomised controlled trial. Ann Rheum Dis. 2018;77(2):188–195.
4. Siemieniuk RAC, Harris IA, Agoritsas T, et al. Arthroscopic surgery for degenerative knee arthritis and meniscal tears: a clinical practice guideline. BMJ. 2017;357:j1982.
5. Kise NJ, Risberg MA, Stensrud S, Ranstam J, Engebretsen L, Roos EM. Exercise therapy versus arthroscopic partial meniscectomy for degenerative meniscal tear in middle aged patients: randomised controlled trial with two year follow-up. BMJ. 2016;354:i3740.

Author: Dr. Michael Minenna D.C., B.Sc., SFMA, FMS — Boreal Spine & Sport, Winnipeg, Manitoba.