The meniscus is the C-shaped cartilage that cushions the knee between the thigh and shin bones. In young people it usually tears when the knee twists in sport, and from middle age onwards it tears through wear [1][3]. For degenerative tears the first treatment is physiotherapy and exercise; keyhole surgery is considered for tears that truly lock the knee or traumatic tears that can be repaired [1][3][4].
What does the meniscus do and how does it tear?
Each knee has two menisci, an inner and an outer. These wedge-shaped, tough and flexible cartilages spread load across the joint surface, absorb shock and contribute to the stability of the knee [1].
Tears come in two forms. In young people and athletes it is usually a traumatic injury from a sudden twist. With age the meniscus weakens, and even a simple turn while getting up from a chair can tear it; this is called a degenerative tear [1][3].
Symptoms
At the moment of injury there may be a pop in the knee. Most people can walk on the first day, but over the next 2 to 3 days the knee gradually stiffens and may swell [1]. Common symptoms [1][2]:
- Pain on the inner or outer side of the knee
- Swelling and stiffness
- A feeling of catching or locking
- The knee giving way, a sense of insecurity
- Difficulty bending or straightening the knee fully
Who gets it, and in what circumstances?
Sports that need twisting, sudden stops and changes of direction, such as football and basketball, raise the risk of a traumatic tear; a meniscus tear can also occur together with other knee injuries such as an anterior cruciate ligament injury [1]. From middle age it can occur without any clear injury and often comes with early arthritis of the knee [1][3].
Diagnosis and the limits of MRI
Diagnosis is made first by examination: tenderness along the joint line is sought and the knee is bent and turned to see whether pain or a click is produced (the McMurray test) [1]. The meniscus does not show on X-ray, but X-rays help separate other problems such as arthritis that cause similar pain; MRI shows soft tissues including the meniscus best [1].
In people past middle age a tear seen on MRI does not necessarily mean the tear is the main cause of the pain, which is why decisions are based on examination and symptoms rather than on the MRI picture [3].
Non-surgical treatment
Many tears, especially degenerative ones, do not need surgery. At first rest, cold, light compression with a bandage and keeping the leg raised are advised; painkillers and anti-inflammatories can be used as the doctor sees fit [1].
For degenerative tears the mainstay is regular exercise with a physiotherapist. In a randomised trial in middle-aged patients, 12 weeks of supervised exercise and arthroscopic partial meniscectomy gave no significant difference in knee function at two years, and thigh muscle strength increased more in the exercise group [4].
An international guideline makes a strong recommendation against arthroscopy in nearly all patients with degenerative knee disease (with or without a meniscus tear), and a Cochrane review also found that arthroscopy gave no meaningful extra benefit in pain and function in this group [3][5].
When is surgery considered?
Keyhole surgery can be considered if symptoms do not settle with exercise and other measures, if the knee truly locks and cannot straighten, or if a young patient has a traumatic tear that can be repaired [1][3].
There are two approaches: in partial meniscectomy only the torn and damaged piece is cleaned out; in repair the torn parts are stitched together. Repair depends on the type and site of the tear, because only the outer part of the meniscus, which has a blood supply, can heal [1]. The decision is shared, weighing age, type of tear, degree of arthritis in the knee and your expectations [3].
Recovery
With non-surgical treatment an exercise programme usually lasts a few months; keeping at it regularly is the most important determinant of the result [4]. After partial meniscectomy recovery takes about 3 to 6 weeks; after meniscus repair longer protection is needed for the tissue to heal and recovery takes about 3 to 6 months; in both, physiotherapy matters for movement and muscle strength [1].
When not to wait
Go to a doctor or emergency department without delay if [2]:
- The knee has locked and cannot be straightened
- It often gives way or clicks painfully
- You cannot put any weight on the leg or the knee looks deformed
- The knee is red and hot and you have a fever
- Pain does not settle within a few weeks
Frequently asked questions
- Does a meniscus tear heal by itself?
- Because its inner part has no blood supply a tear usually does not knit by itself; however, especially for degenerative tears, symptoms often ease markedly with exercise and physiotherapy [1][4].
- Does every meniscus tear need surgery?
- No. For degenerative tears in middle age and beyond the first choice is exercise; surgery comes up with true locking, a repairable traumatic tear or symptoms that persist despite treatment [1][3].
- Can I walk with a tear?
- Most people can walk after the injury; swelling and stiffness may increase over a few days. If the knee locks or gives way see a doctor [1][2].
- When can I return to work after surgery?
- Recovery takes about 3 to 6 weeks after partial meniscectomy and 3 to 6 months after repair; return to work depends on how physical the job is [1].
- Is a tear on MRI a reason for surgery?
- Not on its own; past middle age a tear on MRI may not be the main cause of the pain, and decisions rest on examination and symptoms [3].
At our clinic we decide about surgery not from the MRI report but from whether your knee locks, your age and what you expect from movement.
Sources
- Meniscus Tears. American Academy of Orthopaedic Surgeons (OrthoInfo). orthoinfo.org
- Knee pain. NHS (nhs.uk), 2023. nhs.uk
- Arthroscopic surgery for degenerative knee arthritis and meniscal tears: a clinical practice guideline (Siemieniuk RAC, et al.). BMJ, 2017. pubmed.ncbi.nlm.nih.gov
- Exercise therapy versus arthroscopic partial meniscectomy for degenerative meniscal tear in middle aged patients: randomised controlled trial with two year follow-up (Kise NJ, et al.). BMJ, 2016. pubmed.ncbi.nlm.nih.gov
- Arthroscopic surgery for degenerative knee disease (osteoarthritis including degenerative meniscal tears) (O'Connor D, et al.). Cochrane Database of Systematic Reviews, 2022. pubmed.ncbi.nlm.nih.gov
This article is general information and does not replace an examination or imaging. If you have symptoms, see a doctor.
More in this area
- Anterior cruciate ligament tear: is surgery always needed?
- Baker's cyst: what causes a swelling behind the knee and how does it settle?
- Cartilage damage in the knee: does cartilage heal, and how is it treated?
- Knee injections: what do cortisone, hyaluronic acid, PRP and stem cells do?
- Knee osteoarthritis: exercise, weight, injections and replacement, what and when?
- Knee pain: what causes it, what helps and who should you see?
- Knee replacement surgery: who is it for and what is recovery like?
- Kneecap pain and chondromalacia patella: what causes it and how does it settle?