The “new” meniscus is usually from a donor and is surgically installed and sewn into place where the old one used to be. The surgery is officially called Meniscal Allograft Transplant or MAT. It requires extensive downtime and is often a bigger open, rather than arthroscopic, knee surgery. Make sense? What does the research say?
Does Meniscus Replacement Work?
A recent study sheds some light on the issue of meniscus replacement surgery. In this study, 172 patients had their meniscus replaced. Regrettably about 1/3 needed another surgery within 5 years, the majority of those were within two years. Not encouraging. What do other studies say? A review paper which summarized many studies on MAT concludes the following:
1. So far, long-term research shows that patients who have their meniscus replaced get arthritis like anybody else who has a degenerated meniscus. However, the authors point out that this could be due to older donor meniscus technology.
2. Mid-term failure rates of the donor meniscus, even when the new technology is used, are often as high as 1/3 of cases (i.e. the patient needed another surgery, often within 18 months).
3. Even the newer meniscus replacement technology seems to have issues. For example, when pain and function is used as a metric (which is why most patients go to the doctor), in one study 35% of the surgeries were failures. In the long-term, this study, which also used the newer meniscus technology, showed that 10/15 patients (2/3’rds) had moderate arthritis on follow-up imaging (which the surgery was supposed to prevent). When taken together (pain and imaging changes), less than half of the patients had good results by 10 years. In another larger study, about 1/3 of the patients were failures by 13 years with disappointing average pain and function scores (i.e. the average patient wasn’t functioning well).
4. Patients with any kind of cartilage degeneration at the time of the meniscus replacement surgery generally didn’t do well, so many different combination surgeries have been tried.
The upshot? So does meniscus replacement work? Meniscus replacement surgery is a salvage procedure, meaning it’s done to buy time before a knee replacement. There isn’t convincing evidence that this invasive knee procedure will reduce the amount of arthritis you get, reduce the need for more knee surgeries, or maintain your functioning at a normal level or pain free for long periods of time.