There is considerable debate within the orthopedic community about what the best treatment options are for a meniscus tear. What’s becoming clear is that cutting out the meniscus should really be seen as a last resort. But what about repairing the meniscus?
Newer and better techniques for meniscus repair surgery have been shown to have lower failure rates. And with advances in orthobiologics and cellular therapy, many providers are excited about augmenting these repairs with platelet rich plasma.
But what is the evidence behind this and does it actually lead to better outcomes? Let’s look at this new systematic review and meta-analysis to help answer that question.
The big problem with meniscus injuries is that they do not heal on their own and this has to do with the blood supply of the meniscus. It’s very poor. But what if a surgeon can go inside the knee arthroscopically to repair the meniscus? This would potentially restore the biomechanical function of the meniscus and lead to a healthier knee.
And for this reason, meniscus repair surgery has become an increasingly common procedure. But does it work? This study is a systematic review and meta-analysis of 27 studies looking at 1,630 meniscus repairs. They found that the overall failure rate of a meniscus repair surgery was 19.5% at 5 years post operation. Early generation repairs had a significantly higher failure rate at 30.2% whereas newer generation repair devices had a failure rate of 15.8%.
And depending on who you ask, a 19.5% failure rate at 5 years can be seen as pretty good OR it can be seen as unacceptably high. The concern against meniscus repair surgery has always been its relatively high failure rate. Case in point, old generation repairs had a 30% failure rate. That’s pretty high. So it’s actually great to see that newer generation repairs have a failure rate of around 16%.
Ok so where does PRP come into play? Remember that the idea of a meniscus repair is part of a growing trend to try to do everything possible to preserve the integrity of the joint. This means joint preservation surgeries such as meniscus repairs. And this also means orthobiologic and cellular therapy such as platelet rich plasma injections.
Multiple studies have now shown that PRP injections are superior to alternative treatments such as cortisone injections and hyaluronic acid injections when it comes to decreasing symptoms related to knee osteoarthritis. Other studies have suggested that PRP injections can slow down the progression of arthritis and delay the need for a joint replacement surgery.
So what about combining the effects of a PRP injection and a meniscus repair surgery? Can we use the growth factors and the platelets contained in PRP to further stimulate healing within the meniscus and augment the repair from the surgery.
That’s what this study tried to answer. This is a systematic review and meta-analysis of 9 studies with over one thousand patients. The authors found that the PRP plus meniscus repair group had a significantly lower failure rate than in the non PRP group. Furthermore, the authors report that the PRP group had significantly better pain scores as well as functional scores as measured by the Knee injury and Osteoarthritis Outcome Score system.
So does this mean that everyone who gets a meniscus repair should also consider augmenting their surgery with a PRP injection? In my opinion, if money wasn’t an issue, then yes, you really should consider doing that. But I want to dive in a little deeper to help you understand why this is so important.
You have to remember that the meniscus in the knee plays a critical role in the overall health of the joint. A functional and completely intact meniscus has many different functions including shock absorption, load transmission, joint stability, lubrication, and nutrition. A torn meniscus will lose some of these properties and lead to pain and disability.
This is also why many surgeons previously recommended cutting out the meniscus with a procedure called an arthroscopic partial meniscectomy. The thought was that a tear in the meniscus led to instability of the joint. Cutting out the meniscus tear would restore the stability of the joint and remove the abnormal mechanical symptoms.
But over the last few years, multiple studies have shown that arthroscopic partial meniscectomy is NOT superior to nonsurgical treatment options such as physical therapy. The other problem is that cutting out the meniscus has been linked to increasing rates of osteoarthritis in the knee. It turns out that a torn meniscus is still a functional meniscus when it comes to shock absorption. And by cutting out the torn meniscus, you increase the wear and tear of the cartilage with the end result being more arthritis.
And that’s why there is such a big shift in how we approach both meniscus tears and arthritis. We are now trying everything possible to preserve the joint with joint preservation surgery such as a meniscus repair as well as orthobiologic treatment such as platelet rich plasma injections.
We already know that PRP injections work to treat symptoms related to knee pain. They will help decrease pain and they will help decrease symptoms related to knee arthritis. This is likely why in the study we reviewed, the authors found that the PRP group had much better pain control than in the non PRP group.
You can also think about answering this question from a different lens. Let’s say we have someone who has a meniscus tear but does not want surgery. The best treatment that I can offer this person would be intensive physical therapy focused on strength and stability as well as a PRP injection to help control the micro-environment of the knee. We want to prevent arthritis from getting worse and we want to prevent arthritis from happening in the first place. Both exercise therapy and PRP injections can help with this.
So if I would offer a PRP injection to someone who doesn’t want surgery, then of course I would offer it to someone who does want surgery. At minimum, the PRP injection will help reduce pain and control the micro-environment of the knee. And if the PRP ends up helping augment the meniscus repair, then that would be even better.
So what’s the counter argument to all of this? Well, there is a big limitation of the systematic review. Of the 9 studies included, only two of them were randomized controlled trials. There were 7 that were not. And these 7 studies could introduce biases that can potentially alter the outcomes of the meta-analysis. So until we get more randomized controlled trials, we still won’t know if PRP injections will truly help augment the meniscus repair.
The other thing I want to point out is that patient selection with a meniscus repair surgery is critical. Not everyone can or should be getting meniscus repair surgery. The ideal candidate would be a young patient or athlete who has an isolated meniscus tear in the red red zone and has little to no signs of osteoarthritis. Augmenting this repair with a PRP injection would likely improve outcomes considerably.
Now let’s contrast that with an older patient with a degenerative meniscus tear and moderate or severe arthritis. Unfortunately, this patient’s arthritis will damage the repair and lead to incredibly high retear rates and failure rates. Furthermore, in the course of aging, blood supply to the meniscus decreases even further leading to poor repair success. This patient would likely not benefit from the surgery, but should instead consider a PRP injection to treat the underlying arthritis.
Now that’s not to say anyone over 40 years old cannot get meniscus repair surgery. A recent cohort study looked at meniscus repair outcomes in patients older than 60 years old. They found that clinical outcome scores were higher in the meniscus repair group when compared to the matched meniscectomy group after a few years of follow up. Interestingly they found that the failure rate of the repair group was 22% which is consistent with the systematic review and meta-analysis that I mentioned earlier. But I do have to wonder, would these patients have had even better results if their meniscus repair was augmented with PRP? Maybe! But we just don’t have enough data yet.
What we can conclude from all of these studies is that we should really see cutting out the meniscus as a last resort. Joint preservation with meniscus repair and orthobiologic therapy really seems to be the future of treating knee injuries. Hopefully more data and more clinical trials will help guide us to what the best treatment options are.