MENISCAL INJURY

Overview

The meniscus is a C-shaped, wedge-like “shock absorber” made up of cartilage between the knee bones, femur and tibia. 

They are rubbery cushion-like structures that help to transfer weight across the knee joint thus preventing ensuing arthritis. 

They also provide stability by keeping the rounded femur end over the flat tibia surface.

There are two menisci in the knee, one on the medial side of the knee – this is the medial meniscus & the other rests on the lateral side of your knee – the lateral meniscus.

The meniscus is nourished by small blood vessels; The outer part of the meniscus when injured lacks blood supply and has low chances of healing. Tear of the meniscus is often associated with other ligaments injury.

A tear is most commonly seen in (traumatic) young patients/athletes and (degenerative) in old people. With age, cartilage weakens and tear may occur with low energy injury. 

Types of Meniscal Tear 

Vertical Tear (Incomplete): 

A vertical tear is a common finding on an MRI report. These are primarily signs of early degenerative changes of the meniscus.

Incomplete and intrasubstance tears of the meniscus are stable injuries, and they generally do not require any surgical treatment.

Radial Tear: Radial tears of the meniscus, pictured in the middle of the top row on the image, are the most common type of meniscus tear

These tears are within the avascular zone of the meniscus, where there is no blood supply, and therefore there is little capacity for these tears to heal. Thus, when these tears come to requiring surgical treatment, typically the only option is to trim out the damaged portion of the meniscus

Horizontal Tear: A horizontal tear is a tear that is most commonly amenable to meniscus repair. Seen in the upper right corner of the image, a horizontal tear runs along the circumferential fibers of the meniscus. 

Rather than removing the damaged portion of the meniscus, a horizontal tear may be able to be sewn together.

The key to determining the treatment of these tears is their location. If located within the vascular portion of the meniscus (near the outer edge) then there is healing potential, and thus repair. When located more centrally, these tears will not heal, even if repaired.

Flap Tear: A flap tear of the meniscus, pictured in the bottom left corner of the image, is an unusual pattern of the tear. In circumstances where the flap is causing symptoms of catching in the knee, usually, the flap of the meniscus can simply be removed without removing much tissue at all

Complex Tear: A complex tear means there is a combination of tear patterns. As shown in the middle image on the bottom row, a complex tear often involves both radial and horizontal tear patterns.

Typically complex tears are not treated with meniscus repair because of the complex nature of the tear. In some unusual circumstances, some of the torn meniscus can be removed, while other portions can be repaired.

Bucket-Handle TearA bucket-handle tear is a large type of horizontal tear of the meniscus.

These tears often cause the knee to become stuck by causing the torn portion of the meniscus to block normal knee motion. 

Bucket-handle tears often require more urgent surgical treatment in order to allow the knee to start bending again.

 

Risk Factors

  • Gender: Men > Women
  • Lifestyle: Obesity
  • Activity: Sports activities that require pivoting, such as Basketball, Soccer, Football
  • Age: 
  1. Under 40 years of age: Due to any sports activity
  2. 40 years & above: Due to Ageing

 

Symptoms

The most common symptoms of a meniscal tear are:

  • Pain in the knee joint
  • Stiffness and swelling
  • Catching or locking of your knee
  • Limited motion of the knee joint
  • Knee feels like it might ‘give way’

When left untreated, a broken piece of meniscus may come loose and float into the joint space forming a loose body, or may cause the knee to gradually becomes stiffer & swollen.  

 

When to see a doctor?

  • Not able to move the joint to full functional ROM
  • Severe pain around the knee
  • Knee buckling
  • Rapid Swelling

Diagnosis

 

  • Detailed history
  • Physical examination
  • X-Ray: To rule out other knee ailments depicting similar symptoms as in Meniscal Tear
  • MRI Scan: Mainstay diagnostic modality to detect meniscal tears.
  • Diagnostic Arthroscopy: The arthroscope is inserted in the knee to evaluate the exact condition