Many patients have meniscus tears that are not, in fact, causing their knee pain. There are many other causes of knee pain other than a meniscus tear. Many orthopaedic surgeons and sports doctors see patients with MRI findings of a meniscus tear and knee pain but, after a careful physical examination it is found that the meniscus tear is unlikely leading to the patient’s pain.  In fact, many meniscus tears do not cause any pain at all.

The meniscus is horseshoe-shaped piece of cartilage that sits in between the tibia and femur in the knee.  It acts like a “cushion” to dissipate contact forces between the two bones.  Each knee has two menisci.  There is a meniscus on the inner part of the knee “medial meniscus” and a meniscus on the outer part of the knee “lateral meniscus”. 

The blood supply of the meniscus is better in the peripheral part (red zone) and poor in the central part (white zone).  Because of this, the meniscus does not heals better in the peripheral part compared to the central part.  Attempting to repair meniscus tears in the central portion usually results in failure of the repair. That is why meniscus tears central part are usually trimmed.  Meniscus tears in the peripheral part of the meniscus are sometimes repairable.

• Degenerative/horizontal/complex tears – This is the most common type of tear, caused by age or arthritis.  These types of tears are successfully treated with physiotherapy most of the time.

• Flap or Parrot Beak tear – Can cause intermittent feeling of locking or pain.  In between episodes, can be painless.  If physiotherapy does not resolve symptoms, see an orthopaedic surgeon

• Vertical/Longitudinal – Often associated with ACL tears.  This kind of tear may heal on its own or may be amenable to surgical repair or removal of the torn portion.  

• Bucket Handle tear – A special kind of longitudinal tear where the torn piece has moved into a spot that blocks full straightening of the knee.  If you are young and have just sustained this kind of injury, seek a referral to an orthopaedic surgeon as soon as possible. 

Intrasubstance / Non Surfacing Tears – This is not a true tear, but a precursor to a tear.  It is a change in the consistency of the meniscus within the substance of the meniscus itself, as noted on an MRI report.  It is not usually the cause of the patient’s knee pain.  It can not be visualized during surgery, so treatment for this issue is only non-surgical (physiotherapy). 

• Injury (often twisting of the knee)
• Degenerative changes (wear and tear) due to 
  • Age
  • Arthritis (one of the most common causes) (see below) 
  • Obesity
  • Chronic ACL tear

Often a specific injury can make a previously painless degenerative meniscus tear painful.   

If your doctor suspects a meniscus tear, you need to have standing x-rays of your knee first to look for arthritis. If your knee x-ray is normal and your doctor suspects a meniscus tear as the cause of your pain, then an MRI is required to make the definitive diagnosis.  A knee ultrasound does not do a good job in identifying clinically significant meniscus tears.

If you have knee pain and obvious arthritis on x-ray, you do not need an MRI to look for a meniscus tear. You need to be treated for your knee arthritis.

Most patients with knee arthritis have meniscus tears. There is good evidence to suggest that performing knee arthroscopy on meniscus tears in patients with knee arthritis does not help.  In fact, knee arthroscopy for “a cleaning” in patients with known knee arthritis, is no longer funded by the Ontario Ministry of Health.

Physiotherapy
The initial treatment for most meniscus tears is physiotherapy. This would entail an active-based strengthening program, taught to you by a physiotherapist. The program should concentrate on decreasing your swelling, increasing your range of motion and strengthening your quadriceps and hamstrings.

Physiotherapy can lower or eliminate the pain from meniscus tears, but can not directly heal the meniscus tear itself.  Many patients can become pain-free after doing physiotherapy for meniscus tears. If you do not have pain from your meniscus tear, then no further treatment for those tears is typically necessary.

Injections

For degenerative tears associated with arthritis, various types of injections can be considered to help with the pain.  Note that injections typically act by lowering inflammation.  Injections are not known to “heal” a torn meniscus.

See Section on Injections.

Knee Arthroscopy

Candidates for Surgery

Surgery for meniscus tears is considered for patients who

• Do not have significant arthritis on standing xrays of their knee
• Have tried 6 months of physiotherapy
• Have a meniscus tear that can be either trimmed or repaired

Surgery is also considered expeditiously in the special case of a young patient with a displaced, bucket-handle meniscus tear causing a “locked knee”.

Meniscus surgery is done entirely or is assisted arthroscopically.  An “arthroscope” is a camera on a long, skinny lens, designed to go inside a joint.  The surgery is typically done under a general anesthetic. During surgery, your orthopaedic surgeon will make 2 or 3 small incisions in the knee to allow for the passage of 1)  the scope, 2) specially designed instruments and 3) water management.  (During knee arthroscopy, orthopaedic surgeons inflate the knee a little with water to allow for easier passage of the camera and instruments.) Each incision is about 5mm in size (a fifth of an inch).

Meniscal trimming

Most tears in the central 2/3 of the meniscus need to be trimmed by special instruments so that the torn part does not continue to move around within your knee.  It is hypothesized that this loose part of the torn meniscus is what’s contributing to the pain.   Since meniscus is part of the cushioning of the knee, only the torn portion of the meniscus is removed (“partial meniscectomy”).  In theory, this torn portion is no longer doing its job cushioning the knee and could be causing pain.

Meniscal Repair

Occasionally, in young patients, unstable longitudinal and bucket handle tears in the peripheral portion of the meniscus can sometimes be repaired.  Sutures are placed to stabilize the meniscus, in hopes that the body then heals the meniscus.  If the meniscus does not heal, and the meniscus tear becomes unstable again, it can cause a feeling of locking and a second surgery to remove the torn part of the meniscus is required.  

If a bucket handle meniscus tear is old, the piece that is displaced can shrink or get shredded lowering the possibility of performing a successful meniscal repair.  It is for this reason that young people with a displaced bucket handle meniscus tear see an orthopaedic surgeon as soon as possible.

Patients who undergo partial meniscectomy or meniscal repair are discharged from hospital the same day of surgery. 

Patients who have had a partial meniscectomy are allowed to put full weight on their leg immediately after surgery and are usually able to walk without crutches immediately after surgery. Patients who have had meniscal repair are instructed to partially weight-bear on the operated leg for six weeks after surgery, so will need crutches during that time.

Physiotherapy after Meniscectomy or Meniscal Repair

It is important that you see your physiotherapist within a few days after your surgery in order to decrease your swelling and improve your range of motion and quadriceps strengthening.   During your sessions, your therapists should be teaching you exercises that you can do on your own.  Your therapist should observe you doing the exercises you have already been taught, correct any issues, and teach you new exercises.  You are expected to do those exercises as instructed by your therapist most days of the week on your own.  The further along in your recovery, the less often you need to see your physiotherapist.  

• Partial meniscectomy (meniscal trimming) –  approximately 6 weeks of physiotherapy recommended 
• Meniscal repair (without ACL reconstruction) – approximately 12 weeks of physical therapy is recommended. This is because patients are limited to partially weight-bearing during the first six weeks after meniscal repair.