Knee Joint Anatomy

Meniscus tear is one of the most common knee injuries. Activities causing forcefully twisting knee joint, especially while putting full weight on it, can lead to a torn meniscus.

The knee joint has two C-shaped pieces of cartilage that act like a cushion between your shinbone (leg) and your thighbone (femur).

Each meniscus is divided into three zones

  • Red-Red Zone: This is outer most zone which is highly vascular and so highest chance of healing.
  • Red-White Zone: This is intermediate zone which has good amount of healing potential.
  • White-white zone: This has least amount of amount of healing potential and least Blood supply.

A torn meniscus causes pain, swelling, stiffness and feeling of a block to knee motion and have trouble extending your knee fully.

Each of your knee joints has two menisci:

How common are meniscus tears?

A torn meniscus is a very common Sports Injury. Athletes and people who play sports get meniscus tears. The injury also commonly affects older people and those with arthritis in their knees.

Conservative treatment — such as rest, ice and analgesics medication along with a protective brace are usually enough to relieve the pain of a torn meniscus and give the injury time to heal on its own.

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Symptoms

Torn Meniscus Diagram
Torn meniscus

Meniscus tear causes immediate symptoms, but it might take 24 hours or more for pain and swelling to begin, especially if the tear is small.

Signs and symptoms:

  • A popping sensation
  • Swelling or stiffness
  • Pain, especially when twisting or rotating your knee
  • Difficulty straightening your knee fully
  • Feeling as though your knee is locked in place when you try to move it
  • Feeling of giving way while putting weight

When to see a doctor

Contact your doctor if your knee is painful or swollen, or if you can't move your knee in the usual ways.

Causes

A torn meniscus can result from any activity that causes forcefully twisting or rotating knee joint. Doing lunges, deep squatting or lifting heavy can sometimes lead to a torn meniscus.

In elderly, degenerative changes of the knee can cause meniscus torn with little or no trauma.

Knee Pain Outdoor Representation
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Risk factors

Complications

A torn meniscus if left untreated can lead to a persistent knee pain and one can develop osteoarthritis in knee joint.

Diagnosis

A torn meniscus often can be identified during a physical exam. Your doctor might move your knee and leg into different positions and perform special tests for example: Mc murrays test , Apley's grinding test or Thessaly's test, watch you walk, and ask you to squat to help pinpoint the cause of your signs and symptoms.

Imaging tests

  • X-rays : Because a torn meniscus is made of cartilage so it won't show up on X-rays. But X-rays lets us know about alignment of knee joint and can help rule out other problems which can cause similar symptoms.
  • Magnetic Resonance Imaging (MRI) : This uses a strong magnetic field to produce detailed images of both hard and soft tissues within your knee. I best imaging study to detect a meniscus tear.

Arthroscopy

An arthroscope can be used to examine the inside of your knee. The arthroscope is inserted through a 1 cm incision on knee joint.

The device contains a light source and a small camera, which transmits an enlarged image of the inside of your knee onto a monitor. After visualising inside of knee joint and diagnosing meniscus, surgical instruments can then be inserted through additional small incisions in your knee to repair the tear.

Tears Diagram Overview
Arthroscopic Surgery Procedure
Vascular Zone Cross-section Diagram

Treatment

Treatment for a torn meniscus often begins conservatively, depending on the type, size and location of your tear.

Tears associated with an underlying age related degenerative arthritis often improve over time with treatment of the arthritis, so surgery usually isn't needed. Many other tears that aren't associated with locking or a block to knee motion and which become less painful over time also don't require surgery. The tear in red – red zone and red – white zone usually causes pain and locking in knee joint should be repaired so as to restore normal kinematics of knee joint.

1st line of treatment of meniscus tear:

  • Rest: Avoid activities that aggravate your knee pain, especially any activity that causes you to twist, rotate or pivot your knee. If your pain is severe, using crutches or walker can take pressure off your knee and promote healing.
  • Ice: Use a cold pack or a towel filled with ice cubes for about 10 minutes at a time, keeping your knee elevated. Do this every 4 to 6 hours for first few days. Ice can reduce knee pain and swelling
  • Medication: Pain relievers like NSAIDS can reduces knee pain and inflammation.
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Therapy

Physical therapy can help you strengthen the muscles around your knee and in your legs to help stabilize and support the knee joint.

Surgery

  • If your knee remains painful despite rehabilitative therapy or if your knee locks, your doctor might recommend surgery.
  • It is possible to repair a torn meniscus, especially in children and younger adults.
  • If the tear can't be repaired in badly torn shattered meniscus tear, the meniscus might be surgically trimmed, possibly through tiny incisions using an arthroscope. After surgery, you will need to do exercises to increase and maintain knee strength and stability.
  • In advanced degenerative arthritis: Meniscus repair is not recommended. Your doctor might recommend a knee replacement.

Outlook / Prognosis

What is the prognosis (outlook) for people with a torn meniscus?

Most people who tear a meniscus can return to full activity. If you have surgery to repair a torn meniscus, your knee should be fully recovered after a few months of physical therapy.

If you have surgery to remove all or part of your meniscus for an irreparable meniscus tear especially in neglected meniscus injuries then you may be at a higher risk of developing arthritis in future. That's because you now have less shock absorption in your joint and over a. period of time joint can develop arthritis

Tear Types Microscopic Structural Layout
Femur and Tibia Joint Bone Alignment Diagram

Prevention

Can a meniscus tear be prevented?

It can be hard to prevent an accidental injury. But you can reduce your risk of a torn meniscus if you:

  • Strengthen the muscles that support and stabilize your knee.
  • Wear a knee Brace in case your knee is unstable or weak.
  • Work up slowly to more intense exercise activity.
  • Wear athletic shoes that are appropriate for the sport you're doing.
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Final Note

A knee injury like a torn meniscus can be painful — and frustrating. It can slow you down and keep you from exercising, playing sports or even just walking around the house. Small tears often heal on their own, while others may require arthroscopic surgery.

Work with your sports injuries specialist doctor to develop a treatment and rehabilitation plan that gets you back to your favorite activities — without pain — safely. Most people fully recover from a torn meniscus