Why surgically fix a torn meniscus?
Recently, a comparative study compared sham knee surgery to a partial resection of the meniscus in 45- to 60-year-old people and noted no difference at one year.
In other words, the study seems to suggest that people who just thought they had experienced arthroscopic knee surgery fared just as well as the people who really did have the surgery. If this is the case, you may well be asking yourself: “Is this particular procedure necessary?” If you’ve had this procedure done yourself, how do you know if it really worked or if it was all a placebo?
The first thing to clarify is that the subgroup of people who volunteered to take part in this study did not experience an injury that resulted in an acute meniscus tear. Their meniscus damage was the result of wear and tear over a period of time. Second and more importantly, the fact is that physical therapy alone helps all patients with knee injuries for some period of time. So it is not surprising to me that these patients all seem to be doing well after a year. The difference comes later.
Unfortunately, the data is overwhelming that even small losses of meniscus tissue lead to big changes in force concentration on the tibia (shin bone) and eventually arthritis.
So if the recent study had followed the patients longer, researchers would have realized the disservice done to the patients whose torn meniscus cartilages are ignored. The meniscus is the key shock absorber in the knee. A torn meniscus produces intermittent pain and catching in the knee. The old approach was to tell patients to live with pain until they could not stand it any longer and would eventually have to have a knee replacement.
The new approach is based on the fact that we now have the skills to repair, regenerate and replace the meniscus cartilage. These improved techniques mean that the development of arthritis may not be a fait accompli. The knee mechanics can be restored. The patients can return to full activities without damaging the joint surfaces if the meniscus tissue is anatomically replaced.
So what are the new techniques? If the meniscus is torn, a successful repair depends on stabilizing the tissue and bringing in a new blood supply with repair cells. Improved suture techniques and devices are now available that permit stabilizing even complex tears extending into the root of the meniscus. Growth factors and cell injections provide a stimulus to healing even in the areas without blood vessels. Collagen scaffolds are used to both re-grow the meniscus if segments are missing and to hold cells and blood clots into horizontal splits in the tissue. Partial and complete meniscus allografts (donor tissue) are used to replace the meniscus in pristine knees and even in the setting of advanced arthritis. The new meniscus provides a pain relieving shock absorber permitting the running and impact sports that artificial knees do not allow.
For my patients, I always use physical therapy to optimize the outcome of a knee injury. But I recommend surgery when I know that it will help avoid arthritis and other knee problems in the future. The long-term results count. So when you hear press reports that meniscus surgery is no better than physical therapy alone, think about it; evolution preserved the key meniscus structure for a reason, without its full structure, the knee degrades and life does, too.
(first published in SF examiner)