April 30, 2020 - TCO

Save the Meniscus!

It’s “just a meniscus tear.”  What’s the big deal? 

I’m surprised how often athletes, parents or coaches will breathe a sigh of relief when they hear that an MRI shows “just a meniscus tear.” I believe this is, in part, due to the perpetuated myth that removing the painful portion of the torn meniscus (a meniscectomy) allows for a rapid return to sport or activity with minimal consequences.

The meniscus is the most commonly injured structure in the knee.  This article is my plea for all patients to have their meniscus repaired, as opposed to trimmed out, whenever it is possible.

What is the meniscus and why is it important? 

The meniscus is a collagen-based fibrocartilage disc positioned between the end of the femur and the top of the tibia in the knee.  It acts as a significant shock absorber to protect the highly specialized joint surface cartilage surfaces that provide friction-free and painless motion of the knee.  It acts in concert with the ligaments and cartilage to provide the biomechanical support that allows high energy running, jumping, pivoting and twisting.

Why does the meniscus tear?

The meniscus is prone to tearing when a twisting or shear force is applied to the knee, typically in a bent knee position, leading to the tissue being pinched between the femur and tibia in a focal location. The meniscus can tear in a traumatic fashion where an obvious injury occurs or in a slowly progressive fashion (a degenerative tear).  Traumatic tears can happen in isolation, but often occur at the same time as a knee ligament injury such as an anterior cruciate ligament (ACL) rupture.

What are the main treatment options for a symptomatic meniscus tear?

Unfortunately, the meniscus has a very limited ability to heal on its own based on its limited blood supply, the constant flow of joint fluid in the knee, and the continued forces that are applied across the knee.  Fortunately, not all meniscus tears remain painful, and for degenerative meniscus tears, nonoperative treatment strategies are often successful at relieving knee pain and should be attempted first.

Arthroscopic surgery is the mainstay of treatment for most traumatic meniscus tears and for some degenerative tears that remain symptomatic. Surgery involves placing a camera in the knee and using tools to either remove the torn portion of the meniscus (meniscectomy) or sewing it back together in order to optimize the chances for healing (repair).

Why remove versus repair? 

When determining if the meniscus should be repaired or resected, numerous factors are considered.  This includes careful analysis of the tear pattern, the mechanism of injury, the patient’s activity level and goals, the chronicity of the tear and associated damage to the knee.

Historically, due to concerns over meniscus healing capacity, most symptomatic tears have been managed by removing the unstable portion of the torn tissue.  In particular, chronic or degenerative tears with poor quality tissue, limited blood supply and tearing in multiple planes have less ability to heal and resection may be more appropriate than repair.

Why not just always remove the painful meniscus for a rapid return to sports/activities?

There are always consequences to removing a portion of the meniscus. This decision should never be taken lightly. Any loss of meniscal integrity will lead to an increased load transferred to the cartilage surfaces on the femur and tibia.  The more meniscus that is removed, the greater the stress on the knee.

One study looked at the consequences of removing the meniscus in adolescents and found that these patients had nearly a 90% chance of developing arthritis over the subsequent 40 years, with a 132-fold increased risk of needing a knee replacement.  Pengas IP, Assiotis A, Nash W, Hatcher J, Banks J, McNicholas MJ. Total meniscectomy in adolescents: a 40-year follow-up. J Bone Jt Surg Br. 2012;94:1649–1654

Knowing the mind of athletes, I can already hear the question, “But what will get me back to playing the fastest? I’m not really concerned about what happens years down the road when I’m older.”  I usually look at their parents or coaches at that point and ask them if they still care about participating in athletic activities at their age.  Invariably, they still place a high value on the health of their knees.

I also inform the athlete of the potential short-term consequences of a meniscectomy.  While many patients can return to sports as early as 6 weeks after a meniscectomy, retrospective studies show that between 25-50% never return to their previous level of sport after the meniscus is excised.

Investigations have identified factors that place a patient at higher risk for ongoing knee dysfunction despite removal of the painful meniscus.  These include complex tears, age >30 years, knees with associated cartilage damage, an elevated BMI and lateral meniscus injury.

Why repair versus resect?

The goal of meniscus surgery is to restore the native anatomy of the knee back to its healthy state whenever possible. This can only occur if the meniscus tear heals.  Traditionally, the meniscus was thought to be a structure that rarely heals, even with surgical management.

This thinking has been challenged by numerous studies which have demonstrated that, with modern surgical techniques, maximization of the healing environment, and appropriate postoperative protection and rehabilitation protocols, meniscus healing rates are very predictable.  Excellent results are even more likely when surgical repair is done as soon as possible after the tear occurs.

Given what we know about the critical role the meniscus plays in cushioning, stabilizing, lubricating and supporting the knee, a healed meniscus is always preferable for the long-term health of the knee.

Think long-term and stay fit for life!

Cutting and pivoting athletes will always be at increased risk for damage to the meniscus.  As a physician who has the opportunity to work with athletes of all ages, from the Olympic level to those who are still out heli-skiing in their sixties, I am regularly assessing the best treatment options for preserving the long-term health of the knee, while also trying to safely return the athlete to their sport as soon as possible.

There are numerous influences on this process outside of the surgery itself, including family and coaches.  Often, the coaches who I interact with were once high-level athletes themselves.  It is unfortunate to see how many of them had their meniscus excised during their competing days. Many of them now are dealing with arthritis, and their knees are a regular source of pain.

They provide a valuable perspective on the importance of meniscus preservation.  Together, we should encourage our athletes to think long term about the health of their knees and allow them to stay fit for life without suffering from knee pain.  Excising the meniscus is not without consequence.

What if your meniscus has already been removed and you still have pain?

There are a variety of reasons the knee can still hurt after a meniscectomy.  This may be due to recurrent tearing, ongoing instability of the remnant meniscus, extra stresses placed on the cartilage and underlying bone, or ongoing pain related to pre-existing arthritis.  X-rays are helpful to assess for arthritis and the overall alignment of the knee.  An MRI can be a useful tool to assess the status of the meniscus and surrounding cartilage.

Treatment depends on a variety of factors with the goal to adequately address the true underlying sources of pain.  This may involve bracing, therapy, or surgical management.  Surgery may involve a repeat arthroscopic procedure, a limb realignment, a cartilage transplant, a meniscus transplant or consideration of partial or complete knee replacement if there is advanced arthritis.

I recently had a patient jokingly ask me why we can’t just, “buy a meniscus on Amazon and throw that in the knee.”  Although tissue engineering continues to improve and this is an area that is routinely being worked on, the best option that we have at this time for relieving pain when a meniscus has been completely excised and there is not underlying arthritis, is to use a size-matched donor meniscus to transplant.  Unfortunately, only around 60% of patients still have good results from a meniscus transplant after 15 years, so this option is not without limitation and potential for recurrent knee symptoms.

In summary, my strong recommendation for athletes of all ages is to save the meniscus when possible! 

 -Dr. Jason Holm