Root Tears Of The Meniscus

Root TearsRoot tears are unique types of meniscal tears. In previous posts, we have discussed the various types of meniscal tears, mainly degenerative and traumatic.  Additionally, we discussed a specific type of tear – the bucket handle tear. Now I’d like to discuss another kind – the root tear.

What Are Root Tears?

The menisci are two soft cartilage c-shaped discs that exist in your knee between the end of your thigh bone (femur) and the top of your shin bone (tibia).  They are connected from front to back in your knee. They are fixed peripherally and centrally to the lining, or capsule, of your knee by soft tissue attachments.  The ends of the meniscus, both in the front and back, are connected directly to the bone on the top of your tibia.  These connections are called the roots.  It is here where root tears occur.

Root Tears

Meniscal Root Tear

Root tears can be complete avulsions of the meniscus from the bone – the root pulls off the bone. They can also exist as partial or full tears through the tissue of the meniscus adjacent to the bone. Usually, root tears occur at the meniscal attachment in the back of your knee – the posterior root. More rarely they can occur at the root attachment in the front of your knee – the anterior root.

Who Gets Them?

Several groups of people get root tears more commonly than others. However, anyone can get a root tear.  Like other meniscal tears, root tears can be degenerative – occurring slowly over time from age and “wear and tear”.  They can also be traumatic – occurring acutely in relatively healthy tissue from a mishap.  There are also variances of these two types that don’t fit perfectly into either group.

Degenerative root tears often occur in the presence of arthritis, usually in older people.  Traumatic root tears are seen frequently in association with ACL tears but can result from any activity or injury that causes other traumatic meniscal injuries. Degenerative tears often occur at the posterior root of the meniscus.  Root tears associated with ACL tears are more common in the lateral (outside) meniscus.  A very common subgroup of patients that get root tears, almost always medial and posterior ones, are older obese women with early or advanced arthritis.

What Are The Symptoms Of Root Tears?

The classic symptoms associated with isolated root tears often include an acute “pop” in the back of the knee. Usually, this is followed by significant pain, swelling, reduced motion, and difficulty walking. Over several weeks, severe pain and swelling may improve.  The pain in the back of the knee often persists, however. It is particularly bothersome with walking or twisting.

Why Are They So Bad?

Root tears virtually eliminate the protective function of the injured meniscus.  Having a root tear is like not having any functioning meniscus on that side of your knee.

Why is this bad for your knee?

Your meniscus serves many functions.  Among these are reducing the forces caused by the two main bones of your knee pressing against one another.  The cartilage that protects the ends of these bones is sensitive to forces and degenerates from excessive pressure. Wear and loss of this cartilage are what we call arthritis.  Arthritis can cause disabling pain, swelling, stiffness, and a slew of other symptoms that can adversely affect the quality of your life and ability to perform many of your daily activities.

Since the meniscus is no longer working to protect your cartilage when you have a root tear, the cartilage can deteriorate rapidly and lead to rapid and early arthritis. In fact, up to 30-50% of people who sustain a root tear require a knee replacement within five years. Not everyone will. But often they can, and that is why these injuries are so worrisome.

Not only can root tears cause arthritis but arthritis can cause root tears. As the knee degenerates, everything in the knee degenerates, including the meniscus. As the knee goes through this deterioration, the space between the bones collapses, and this can “squeeze’ the meniscus, tear the root and “push” the meniscus out of the knee (extrusion). In this case, the root tear may actually not be a source of your symptoms but can be an ominous sign of a more significant developing problem – progressive arthritis.

How Are They Diagnosed?

Root Tears

MRI – Posterior Medial Meniscal Root Tear

For those of us who often treat meniscal tears, this diagnosis is often suspected simply from your description of your injury and symptoms. As mentioned above, usually there will be a “pop” in the back of your knee with persistent pain in that same location.  On exam, there may be fluid in the knee (effusion), some initial loss of motion and often very focal bone or joint tenderness on the side of the knee where the tear is.

X-rays are critical – not so much for the diagnosis, but to help eliminate other sources of pain, particularly evidence of preexisting arthritis.  Also, once a tear is diagnosed, X-rays are essential in helping to direct the appropriate treatment.

Jeffrey Berg, MD

MRI – Bone Bruise

An MRI is diagnostic.  It often shows the tear clearly.  It can also show extrusion of the meniscus if present. Furthermore, there may bone bruising (edema) in the adjacent bones from the acute trauma or increased stress on the bone due to the meniscus no longer functioning. Finally, MRIs can define the extent of preexisting arthritis. This information is critical in determining the proper treatment plan.

What Are The Treatment Options For Root Tears?

Work is still underway to determine how to treat these injuries in all cases. There are three options: Observe the tear, and only treat the symptoms, remove the torn piece (Meniscectomy), and repair the root back to the bony attachment.

Several factors determine the best treatment.  There are the usual surgical factors: health, willingness for surgery, etc. There are also factors specific to root tear treatment. The presence of knee arthritis, quality of the meniscal tissue, and the patient’s ability or desire to comply with a postop repair regimen (no or limited weight-bearing on the surgical leg x 4-6 weeks) are some of the more important considerations.

Meniscal Repair

There are two reasons for surgery: 1) Reduce or eliminate pain, and 2) Prevent arthritis. Repairs of meniscal tears in general, and root tears specifically, are performed to not only end the symptoms but also to prevent the development of osteoarthritis.  Since the progression of existing arthritis cannot be slowed or reversed, if you already have significant knee arthritis, there is no reason to repair your root tear – the risks outweigh any potential benefits. Now, if there is mild arthritis or arthritis in a location distant from the injury, a repair may be considered. If there is no arthritis in your knee and you are able and willing to follow the postoperative restrictions and recovery timeline, a repair of the tear is often the preferred option.

Meniscectomy

What about trimming the torn piece?

Although this may provide short-term relief of your pain and swelling, because of the unique nature of these types of tears – a complete tear renders the meniscus nonfunctional – the long-term results differ from other types of meniscal tears treated this way.

Whereas in other meniscal tears, removing small pieces of the meniscus is a reliable treatment, in many cases, that same approach in root tears has a worse long-term outcome.  When removing a small portion of a typically torn meniscus, the function of the meniscus is only reduced somewhat, depending on how much of the meniscus is involved.  Furthermore, many of these tears would not heal even if repaired. So the option in these cases is to either leave the torn and painful piece, which isn’t helping to protect the knee anyhow, or remove the torn part. in this case, meniscectomy will reliably eliminate the pain and has the same risk of arthritis as if the piece was left alone.

With root tears, the situation is much different.  Removing the piece may improve your pain, but since the meniscus is functionless without repair, the knee will often progressively deteriorate, sometimes rapidly. That’s not to say it never should be done, but like other surgeries, you should know what the surgery can accomplish and what to expect going forward. When treated in this fashion, many of these will have the same mid- to long-term outcome had no surgery been performed. As a result, often when a repair is not feasible or desirable, observation and symptomatic treatment, despite not preventing further knee deterioration, may actually be the best option for you.

Root meniscal tears are unique meniscal tears that can occur in anyone but are more common in older people, particularly those with an arthritic knee.  Depending on the status of the knee, these may indicate a progression of arthritis or, without treatment, a progression to arthritis.  If you have a meniscal root tear, it is critically important that you see an orthopedic sports medicine and knee specialist to ensure that you get the correct treatment.

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