For many years, the meniscus, commonly thought of as the knee cartilage, was treated as though it wasn’t that important. If the meniscus tore, doctors would simply take it out. But this procedure–called meniscectomy–can have disappointing results.
The menisci act as shock absorbers in the knee, forming a gasket between the shinbone and the thighbone. It is now known that taking the meniscus out leaves the knee joint unprotected and prone to arthritis.
Thus, researchers have been exploring meniscal transplants as a possible solution after a torn meniscus has been removed. In this surgery, doctors use the meniscus from a cadaver knee (allograft) to replace a patient’s meniscus. The short-term results have been fair. These authors report on mid-term results for meniscal transplants after total meniscectomies.
In this study, meniscal transplants were done on 23 patients who had knee pain after meniscectomies. The day after the transplant, patients did leg exercises and started to move around. They returned to their normal activities six to nine months later. They were told not to do aggressive sports or distance running after the transplant.
Eighteen patients with 22 transplants were contacted an average of five years after surgery. Eleven of the patients were men; seven were women. Their average age at the time of transplant was 30. The average time between the meniscectomy and transplant surgeries was eight years. Half of the patients also had ACL reconstruction at the same time as the transplant.
Eight of the transplants (36 percent) tore after surgery. The average time to tear was two and a half years. Most happened because of some sort of trauma. The torn menisci were then fully or partially removed. Pleased with how their knee felt after the transplantation surgery, two patients who had torn the allograft asked to have the procedure again.
In general, though, patients did better after having their menisci replaced. According to questionnaires, their pain improved dramatically after surgery, as did their physical and social functioning. This was even true for those requiring another surgery to fix a torn transplant. Even with these improvements, however, most patients still showed some problems in their overall function at follow-up.
The authors were pleased to find that the outer edge of the transplants healed completely to the nearby tissues. Notably, however, the number of cells was lower in the transplanted tissue than in patients’ natural menisci. Also, the cells in the transplants didn’t function as well and produced fewer nutrients. This may explain why transplants were prone to tears.
The authors conclude that meniscal transplants can reduce pain and improve patient functioning. X-rays showed that this procedure helps prevent wear and tear on the joint. However, studies are needed to see the long-term benefits of this type of transplant surgery.