The meniscus surgery conumdrum

In the United States there are approximately 850,000 people undergoing meniscal surgeries every year.  Are you—or somebody you know—on the fence and unsure of where to turn?  We at 3DPT are here to help you decide.

                                                              

                                                          

                                                        Meniscus Structure and Function

Let’s back up a little.  First, what exactly a meniscus is may be a key factor in your decision.  The meniscus is located in the knee joint.  It is made up of 2 cartilage-like discs that act as functional extensions of the normal cartilage found within the knee.  It acts to increase the contact area between the relatively round end of the femur (thigh bone) and the relatively flat end of the tibia (shin bone) therefore decreasing the amount of stress on the knee cartilage.  This larger contact area is essential to normal function of the knee, as its absence would cause undue stress on the normal cartilage found within the knee eventually causing arthritis.

My MRI says I have a torn meniscus.  What are the options?

So you were running or walking along a sidewalk one day and landed on a funny uneven surface and tweaked your knee.  Actually, that tweak probably felt more like an explosion.  Now you’re in the doctor’s office and you’re told that imaging studies show your ACL is fine (phew!), but that you have a torn meniscus.  There are a few routes that people typically go from here and why you should choose one from another depends on a number of factors.  The typical options are meniscectomy (take out the damaged part of meniscus), meniscal repair (reattach the torn meniscus), and/or physical therapy.

                                                Which route is best for me?

This question is very difficult as the answer depends on many different factors specific to every individual.  Here is the type information we feel that you should know in order to make an informed decision for yourself.

Meniscectomies are surgeries performed to remove a piece of torn meniscus.  Why take out a piece of meniscus you ask?  Two thirds of a normal meniscus essentially has no blood supply, making it nearly impossible to heal.  Also, sometimes a piece of the meniscus can get stuck in a bad position making it difficult to move the knee correctly.  Therefore a logical option is to simply take out the damaged bit.  Unfortunately, studies have shown that this can cause even worse repercussions down the road.  One study¹ published in 2008 by Mills and colleagues showed that knee cartilage defects are much more prevalent in people who had undergone meniscectomies than in healthy control subjects  (77% vs 42%) after just 3-5 years after surgery.  This suggests that people who have a piece of their meniscus taken out are more prone to knee arthritis.  Why is this?  That meniscus is such an important player in the cushioning and distribution of stresses on knee cartilage that when even a piece of it is taken out the cartilage takes too much of the load and rapidly breaks down.

Meniscal repairs are surgeries that began to be performed in response to the knowledge of this problem with meniscectomies.  Surgeons basically tie down the torn part of the meniscus to prevent it from flapping back up and promote healing.  For tears in the small region of the meniscus that has blood supply this may be a better option.  This surgery allows for the contact area of the knee joint surfaces to stay roughly the same as before.  The only down side here is that you will still have to undergo surgery.  Not only is surgery in general a scary thought, but it can also be detrimental to long term function.  Multiple studies^2,3 have shown low participation in usual functions and strength in people undergoing meniscus surgery as far as 4 years out.

Physical therapy is the conservative approach to treating meniscus tears.  As much as I would like to tell you that physical therapy can heal your meniscus, that region of very little blood supply will likely not heal via any method.  Physical therapy will focus on stretching, strengthening, and improving the way your body moves in order to decrease the amount of stress that your knee takes.  Perhaps the real beauty of physical therapy with meniscus injury is that the meniscus stays in the knee where it was meant to be.  The thought is that even a damaged meniscus is better than no meniscus.  Earlier this year a study published in the New England Journal of Medicine showed essentially no difference in outcomes for people who participated in physical therapy rather than surgery⁴ after 6 and 12 months.  For physical therapy as a profession this was huge.  We can have the same affects on knee recovery as surgery, without the negative effects of cutting into you or the arthritis down the road.

Jamie Rosenberg, SPT

1)   Mills PM et al. Tibio-femoral cartilage defects 3-5 years following athroscopic partial medial meniscectomy. Osteoathritis and Cartilage. 2008; 16: 1526-1531     

2) Muscle strength, functional performance, and self-reported outcomes four years after arthroscopic partial meniscectomy in middle-aged patients.  Arthritis & Reuhmatism. 2006; 55 (6): 946-952

3) Roos EM et al.  Substanstial disability 3 months after arthroscopic partial meniscectomy: a prospective study of patient-relevant outcomes.  Jour of Arthro and related surg. 2000; 16 (6): 619-626.   

4) Katz JN et al. Surgery versus Physical Therapy for a Meniscal tear and osteoarthritis.  The New Eng Jour of Med. 2013; 368 (18): 1675-1684.