Does Meniscus Surgery Help? Taking Out a Torn Meniscus Makes the Knee Joint Unstable
Does meniscus surgery help? I see patients everyday who have had their knee “fixed” via arthroscopic “repair” of a torn meniscus. The pain goes away for awhile, but then returns with a vengeance. Almost 100% were unaware when they had the knee surgery that it’s been shown to be no better than physical therapy or no surgery. Even once they’re made aware of that research and find our clinic looking for an alternative to a second knee surgery or a knee replacement, they don’t fully appreciate that the surgery they thought would fix their knee, has actually made it more unstable, accelerating the inevitable march towards full blown arthritis. Now a new study further supports this concept, showing that taking out the meniscus causes knee instability.
The knee meniscus is a spacer and shock absorber for the knee. Tears in the meniscus can cause pain, but most meniscus tears in middle aged and older patients go unnoticed as research has shown that meniscus tears in this group are a bit like grey hair, they are an inevitable consequence of aging. Despite this realization that meniscus tears are common and usually don’t cause pain, when a patient has knee pain and an image is ordered, if a meniscus tear is seen (which is likely not the cause of pain), a surgery usually follows. Most patients believe that the knee surgery will “repair” their torn meniscus, but again, research shows that the vast majority of the time, this isn’t what happens. Instead, the torn piece of meniscus is simply removed, leaving less spacer. This decreased shock absorption then leads to more arthritis over time.
Most patients don’t know that taking out all or part of this spacer results in an unstable knee. What does this mean? The knee has strong ligaments that allow it to be stable, which means that the cartilage surfaces will glide normally. When one or more of these ligaments becomes lax, the knee becomes unstable, increasing the wear and tear on the cartilage. Bone spurs then form to try to stabilize the knee. I see this instability everyday while examining meniscus surgery patients with ultrasound. Every time these patients run, jog, walk or play sports, their meniscus is now moving in and out of the joint as their joints bends slightly sideways due to the lax ligament (medial or lateral collateral). In my experience, it doesn’t take long before more and more arthritis is seen in these patients.
This new study looked at this issue in more detail than my casual stress ultrasound exams. They took 60 patients who had most of their meniscus removed due to a big meniscus tear and compared them to 21 patients who had normal knees. The total side to side bending of the knee (instability) increased 33%! There was also a 38% decrease in stability when bending the knee. In addition, the mensicus surgery patients seemed to get more unstable over time.
The upshot? There is little research evidence to support that knee meniscus surgery is effective. There is evidence showing that it may lead to more arthritis. Now there’s evidence showing it increases instability in the knee!