It’s clear now that a torn meniscus (cartilage) in the knee should be repaired whenever possible. The previous practice of surgically removing the meniscus resulted in early osteoarthritis. So that practice has been abandoned unless it’s completely unavoidable for some reason. Now, the next debate is whether the meniscus should be repaired at the same time as an anterior cruciate ligament (ACL) tear when these two injuries occur at the same time.
Studies have shown that complex knee injuries that damage more than one structure have the best results when everything that’s torn loose is repaired or reconstructed. But surgeons are still studying the effects of doing one repair at a time versus completing all repairs during the same procedure. Toward that end, this study was designed to evaluate the results of surgery for an isolated meniscal repair versus complex repair (meniscus and anterior cruciate ligament).
The main feature of this study that separates it from others is the fact that the patients were all children or teenagers. All 99 subjects included were 18 years old or younger. This is the largest series published for this problem in this age group. Everyone in the group was treated for a complex injury by arthroscopic surgery. Everything that needed fixing was taken care of in one fell swoop. Specific surgical techniques and methods of fixation are reported by the authors in a table for surgeons who might be interested in this information.
The results were compared with a second group (48 patients) in another study by the same authors of this study. In that previous study, only the meniscus was damaged and then repaired. There were patients treated by these surgeons who had a staged procedure (first a meniscus repair and later reconstruction of the torn ligament) but these patients were excluded from this study.
Just what were the results compared? Lots of things — knee range of motion, stability of the joint, pre- and post-op X-rays, and function. Function was assessed by looking at the activity level before injury, just before surgery, and after surgery. Everyone was in a rehab program after surgery and treated with the same protocol. Since this was a young group of patients who injured their knees, a high level of sports and recreational activity was reported prior to the injury.
Return-to-sports involving sudden changes in direction (pivoting and cutting) was allowed six to nine months after surgery for those with complex injuries before surgery who demonstrated good knee stability after surgery. Patients with just a meniscal tear were able to return to their pre-injury level of sports participation much sooner (four to six months after surgery) if the meniscal repair was successful. And success was defined as no pain (or only mild pain) and no locking, catching, or swelling of the knee. Long-term success is measured by the re-tear rate.
In the group of 99 patients, 90 per cent were tear free after two years. Persistent pain and other symptoms were still present in one-fourth of the group, so the overall clinical success rate was 74 per cent. Five years after surgery, the freedom-from-failure rate dropped to around 77 per cent (down from 90 per cent after two years). One-fourth of the group ended up with a failed meniscal repair and required a second operation.
Risk factors for poor results included participation in a high-demand sport after surgery, the original injury being a complex tear (meniscus and ligament), and a particular type of meniscal tear called bucket-handle tear. Type of surgical repair technique used in the first surgery was not a factor in the failures. For those who had to have a repeat surgery for failed meniscal repair, the majority (two-thirds) had to have part of the meniscus removed. Only one-third of the group could have a re-repair.
Now how did the group of 99 patients with complex tears compare with the 48 who only had an isolated meniscal repair? The complex repairs had a better success rate. That was true no matter what type of meniscal tear was present in the complex injuries. When the only damage done by the injury was to the meniscus, the type of tear (simple versus bucket-handle) didn’t result in differences in outcomes — only when the meniscus was part of a more complex injury.
The authors conclude that they met their own objectives in carrying out this study. They found out the success and failure rates of meniscal tears compared with complex tears in adolescents. They discovered some risk factors that help predict outcomes. And they saw the differences in results when menisci were repaired by themselves versus when the repair is done as part of a meniscus plus ligament repair.
They offer some significant buts at the end of the article that strongly suggest further study in this area is needed. For example, there were five different surgeons involved and the procedures were done over a period of 15 years. A lot can change in that time as surgeons gain experience and as surgical techniques change over time. Some of the 99 patients were skeletally mature (had stopped growing) at the time of the injury, while others had open physes (were still growing).
Not everyone had an X-ray taken during the follow-up visits. It was assumed that anyone who was pain free and had no other symptoms to suggest a problem had a successful result. But it is possible that undiagnosed retears were present in those patients. And finally, healing rates can be highly variable in this age group.
Any of these factors could affect the results as measured in this study. The authors consider this project a springboard for future investigations to further identify other prognostic factors predictive of success/failure. With additional research, they also hope to clear up any other issues around when and how to repair complex knee injuries involving meniscus and ligaments in active teens.