In this series we will look at some of the most common injuries and conditions that can result in either chronic or acute knee pain. If you have experienced knee pain as the result of an awkward fall, twisting your knee as you did or if you noticed a sudden ‘pop’ in your knee joint – you might have experienced a meniscal tear. To make matters worse, as we age, these kinds of tears become easier to come by, with less and less effort on our part.

What is the meniscus? 

Your menisci are incredible crescent-shaped shock absorbers that live in your knee joint, forming a cushion between your femur (thigh bone) and your tibia (shin bone). Made from cartilage, each meniscus is composed of three distinct zones: the peripheral component, known as the redzone, which is made of type I collagen and has a modest blood supply to it and the remaining two-thirds of the meniscus which are called the ‘white zone’ and are mostly made up of type II collagen with absolutely no blood supply. In between the two is a transition zone that has some of the characteristics of each of its neighboring zones – aptly called the red-white zone. Each knee has two menisci, the medial and the lateral, and together they help keep the joint happy by distributing downward force, out and away.

Each knee has two menisci that function as shock absorbers, dispersing force out and away.

How are they injured?

A meniscus tear occurs when the rotation of the femur pinches and tears the meniscus – this is often the result of a forceful twist or rotation of the knee. A common injury in sports such as soccer and skiing, meniscus tears can also occur when lifting something heavy, squatting or kneeling. 

As we age, our joints, ligaments and cartilage begin to show signs of wear and tear. The culmination of past injuries and the worn cartilage of the meniscus can also result in a damaged meniscus, without having to suffer a traumatic injury.

What are the symptoms of a damaged meniscus?

A meniscus tear might not seem obvious after an injury is sustained – some might feel a ‘pop’ in their knee during the incident, yet many people can continue to walk or even resume sports immediately after they have sustained a traumatic injury to the cartilage in their knee. 

Two or three days later, however, you may begin to notice some pain, stiffness or a locking or sticking sensation in your knee. It may feel like your knee could ‘give-way’ or you may notice a limit in your knee’s range of motion. If you were to place your hand on your knee, you may feel a rough sensation as your joint moves – this could be a sign that your femur is gliding along a damaged or degenerating meniscus.

A meniscus tear may be misleading – it may not hurt right away and you might not think anything is wrong.

How are meniscus tears treated?

How well a meniscus will heal is dependent on what caused the injury and where on the meniscus the tear is located. For a young athlete who experiences a tear to their red-zone – the outer one-third of the meniscus with adequate blood flow – there is a good chance that along with rest, ice, compression and elevation (R.I.C.E) the injury will heal on its own. If however, the damage is to the inner two-thirds – the white zone with no blood flow – or is the result of a degenerated meniscus – the answer is a bit more complicated.

Researchers at the University of Pennsylvania who were examining the complex mesh of fibers that run criss-cross in the meniscus found that these fibers have a unique ability to maintain knee integrity in the event of a meniscus injury. They found that incredibly,  the severed circumferential fibers could maintain mechanical functionality of the meniscus with as much as a 90% tear through it – another sign that our bodies are composed of some of the most sophisticated and effective systems imaginable. 

For some patients an immediate anti-inflammatory response is needed – for example if the swelling in the joint is so severe that walking has become difficult. In that case, we may inject steroids into the joint to calm down the inflammation response. For patients who are experiencing a lot of meniscus degeneration, to the extent that their joints are now grinding together, we have had a lot of success injecting hyaluronic acid directly into the knee joint – a substance found naturally in our bodies as a natural joint lubricant. While these treatments may help alleviate some of the painful symptoms associated with a torn meniscus, they do very little to heal the damaged tissue.

Using an ultrasound to inject Platelet-Rich Plasma into the knee.

The best treatment for serious injuries to the meniscus are regenerative therapies such as PRP (platelet-rich plasma) and stem cell therapies – ways in which we can help the body heal itself. Both types of therapies trigger the body’s natural healing response, albeit in different ways, by either signaling to neighboring cells that help is needed or becoming the cells needed to repair the damaged tissue. Physical therapy and strengthening exercises are also key components for rehabilitating the knee and helping to prevent future injuries. For more information on PRP, click here.

Is surgery the solution?

For the vast majority of people who suffer a meniscus tear or degeneration – the answer is a resounding no. Despite the fact that surgery should only be used as a last resort – when all other treatment options have been exhausted – knee surgery is one of the most common surgeries in the US with millions of meniscus tears being operated on each year. This, despite the fact that meniscus surgeries and arthroscopies have been shown to be relatively ineffective at treating the pain or loss of mobility associated with a meniscus tear. A recent study in the British Medical Journal went so far as to state that meniscus surgery was “a highly questionable practice without supporting evidence of even moderate quality.” Furthermore, studies are showing that this type of surgery is actually contributing to more severe and debilitating forms of osteoarthritis in the future. One could say that meniscus surgeries are ‘cutting the meniscus to spite the knee’. 

Can a meniscus injury be prevented?

It is important to remember that there is no better way to prevent an injury than by being healthy and active. Despite the fact that some meniscus tears occur as the result of a traumatic injury (such as being tackled!), most of the meniscus issues we see are as a result of both aging joints and a loss of muscle conditioning. Without the support of strong surrounding muscles we increase the risk that a simple everyday movement could cause a painful tear in our meniscus. Keeping active and engaging in both aerobic exercise and strength training are two of the best ways to keep your joints and everything they support – happy and healthy.