Latest / The ACL Athlete Podcast / 093 | Is Numbness Normal after ACL Surgery? Part 1

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093 | Is Numbness Normal after ACL Surgery? Part 1 · The ACL Athlete Podcast

• 0:19
  SPEAKER_00: Welcome everyone to the ACL Athlete Podcast.
• 0:23
  SPEAKER_00: This is the podcast where we talk about everything related to the ACL, whether that's the injury itself, the rehab process, return to sport, and more.
• 0:33
  SPEAKER_00: I'm your host, Dr.
• 0:34
  SPEAKER_00: Ravi Patel, performance physical therapist and coach.
• 0:38
  SPEAKER_00: Between myself and fellow guests and experts, you'll learn through the lens of the patient, the healthcare professional, and the coach.
• 0:46
  SPEAKER_00: The goal of this podcast is to equip you, the athlete, with the education to make the best informed decision about your care and your ACL journey.
• 0:57
  SPEAKER_00: Thanks for joining.
• 0:58
  SPEAKER_00: Now let's dive into today's episode.
• 1:03
  SPEAKER_00: What is up, team?
• 1:05
  SPEAKER_00: We are back this week in full force.
• 1:08
  SPEAKER_00: My voice is almost back to 100%.
• 1:10
  SPEAKER_00: And for those of you who listen to showing up in your ACL rehab, bless your soul and thanks for sticking it out with me.
• 1:19
  SPEAKER_00: And I'm excited to dive into this two-part series where we are going to answer the question Is numbness normal after ACL surgery?
• 1:28
  SPEAKER_00: And today we are diving into part one where we are going to talk about numbness and a little bit of the details, diving into it and giving you guys a little bit more background and why it happens.
• 1:41
  SPEAKER_00: And this is a super common question I get from almost every athlete we work with.
• 1:46
  SPEAKER_00: And I get this from social media all the time is numbness normal?
• 1:50
  SPEAKER_00: How much is normal?
• 1:52
  SPEAKER_00: When can I expect things to be normal?
• 1:54
  SPEAKER_00: All these different pieces of understanding what's going on.
• 1:58
  SPEAKER_00: And we're hoping that this two-part series is really gonna help answer that.
• 2:02
  SPEAKER_00: And I'm kind of excited to geek out on this.
• 2:04
  SPEAKER_00: So I hope you guys are ready for a little bit of like some anatomy lessons, but more so getting to the root cause of what is going on, why does it happen?
• 2:13
  SPEAKER_00: And so let's jump right in.
• 2:15
  SPEAKER_00: So I'm gonna go ahead and answer the very straightforward question is numbness normal after ACL surgery?
• 2:22
  SPEAKER_00: The short answer is yes, it is very common.
• 2:26
  SPEAKER_00: So let's dive into why it's so common and what exactly is going on.
• 2:31
  SPEAKER_00: But first, let's define what numbness is.
• 2:34
  SPEAKER_00: And the technical term for numbness is paresthesia, and that is something that you'll hear maybe medical doctors use or in the literature, but we're gonna really focus on numbness because that's what most ACLers feel after surgery.
• 2:50
  SPEAKER_00: And numbness is really a change and especially a loss of sensation in a certain area.
• 2:56
  SPEAKER_00: Sometimes it can come with other symptoms like tingling or changes in temperature.
• 3:01
  SPEAKER_00: Sometimes it can be that prickly type sensation, the pins and needles type feeling.
• 3:06
  SPEAKER_00: This is typically a sign of something neurogenic or what we say is coming from a nerve.
• 3:12
  SPEAKER_00: Now, everyone has experienced this in one way or another.
• 3:16
  SPEAKER_00: You've probably fallen asleep on your arm in an awkward position, you might have sat in your seat for a certain position for too long, and your foot falls asleep, or maybe you feel those pins and needles in the bottom of your foot.
• 3:28
  SPEAKER_00: Now, this is a little different than ACL surgery itself, but this will help to explain what exactly is going on.
• 3:35
  SPEAKER_00: When this happens to you, this is usually because of a nerve is being compressed or maybe stretched and leading to a compression on those arteries that provide blood to the nerve.
• 3:47
  SPEAKER_00: This limits oxygen and glucose to the nerve, causing it to fall asleep.
• 3:53
  SPEAKER_00: Once the position is changed or the compression is moved, usually it bounces back and wakes up, right?
• 3:58
  SPEAKER_00: We all know this, but it's different when we're talking about ACL surgery to some degree, and it'll make more sense as we continue on.
• 4:07
  SPEAKER_00: Now for a brief anatomy lesson.
• 4:09
  SPEAKER_00: So let's talk about how the anatomy plays into this numbness that you feel at your knee.
• 4:16
  SPEAKER_00: So, what I want you to visualize is basically your nerves kind of like a tree.
• 4:20
  SPEAKER_00: So visualize that tree.
• 4:22
  SPEAKER_00: You have the top parts of the tree, and then you have basically the roots and the trunk and all the small ones off of those little roots.
• 4:31
  SPEAKER_00: This is kind of how our nerves work.
• 4:33
  SPEAKER_00: You got your kind of brain at the top, you've got your spinal cord, and then you have these nerve roots that are coming out.
• 4:39
  SPEAKER_00: From there, you have smaller ones and even smaller ones that branch off of each of every one of those.
• 4:46
  SPEAKER_00: Now, to keep things super simple here, we're gonna break these down into two different types of nerves that come out.
• 4:52
  SPEAKER_00: One is sensory and one is motor.
• 4:55
  SPEAKER_00: Sensory is the input, motor is the output.
• 4:59
  SPEAKER_00: Sensory nerves provide senses for touch and pain, temperature, vibrations, etc.
• 5:05
  SPEAKER_00: And it gives our brain info about the environment around us.
• 5:09
  SPEAKER_00: When you close your eyes but you can still touch your elbow, you know what's happening, and it's due to sensory info going in and the nerves providing that to our brain.
• 5:18
  SPEAKER_00: Motor nerves create the output, the function, or typically the action or the movement.
• 5:24
  SPEAKER_00: Bending the knee, engaging the quads, whatever movement that happens within your body, that is all a motor output.
• 5:31
  SPEAKER_00: And so we're gonna skip ahead here for just a second.
• 5:34
  SPEAKER_00: But what's impacted in your ACL surgery is a specific sensory nerve called the infrapetellar branch of the saphanus nerve.
• 5:43
  SPEAKER_00: Luckily, this does not impact function in most cases, since it is not a motor nerve, it is a sensory nerve, so it does affect sensation, mainly that numbness that most of you ACLers feel.
• 5:57
  SPEAKER_00: So let's keep rolling with this anatomy lesson here.
• 6:00
  SPEAKER_00: So the anatomy of the infrapetellar branch of the saphenus nerve.
• 6:05
  SPEAKER_00: And one thing I do want to point out before we dive into this is that remember that everybody's body, like your actual human body, is a little different.
• 6:14
  SPEAKER_00: But this is going to be a general anatomy overlook for just like the general population and for most people.
• 6:20
  SPEAKER_00: So the origin of this infrapetellar branch of the saphenus nerve actually starts up at the spinal cord.
• 6:28
  SPEAKER_00: And so the spinal cord creates these nerve roots that come out of our lower back, and they form to create the femoral nerve and sciatic nerve and some other nerve branches.
• 6:37
  SPEAKER_00: But these are the main ones that are kind of going into our lower body and innervate our lower extremities.
• 6:43
  SPEAKER_00: Now, the main focus here is the femoral nerve, which runs to the front part of the hip and the front side of the body, and then it goes down this path through muscles along our groin called our adductors, and then it comes out and then it starts to split once it gets near the inside medial part of the knee and down the lower leg.
• 7:04
  SPEAKER_00: When it gets to that inside part of the knee, near the sartorius and gracillus tendons, these are your inner hamstring muscles.
• 7:12
  SPEAKER_00: So just think on that inner side, it branches into the saphenus nerve and the infrapetellar branch of the saphenus nerve.
• 7:20
  SPEAKER_00: To give you a solid visual here, just imagine there is a nerve that goes through the front part of the hip and then towards the inner part of the groin and then to the inner side of the knee, and that's where we're at right now.
• 7:32
  SPEAKER_00: So that saffinous nerve continues down the leg and it is responsible for allowing people to feel sensation from the inner side of the knee and down towards the ankle on that inside area.
• 7:45
  SPEAKER_00: And one of the things with that infra patellar branch is where that inside of the knee and more towards the front of the knee is where it starts to provide a sensation.
• 7:55
  SPEAKER_00: So if you were to take basically the palm of your hand, and if you were to cover the inside to the front side of your knee, that's basically where that branch will help innervate and provide sensory feedback.
• 8:08
  SPEAKER_00: And it crosses over basically the front of that knee joint and even beyond that.
• 8:13
  SPEAKER_00: And I'm sure you know where I'm going here.
• 8:15
  SPEAKER_00: When you think about the incisions made in your ACL surgery, there's typically insertions made around this area.
• 8:22
  SPEAKER_00: And one of the things before we move forward is I want to mention some other nerves that might play a role, but is not nearly as common.
• 8:31
  SPEAKER_00: The medial sural cutaneous nerve, the lateral sural cutaneous nerve, and the lateral femoral cutaneous nerve.
• 8:38
  SPEAKER_00: I want you guys to really ignore all of these names for the most part.
• 8:42
  SPEAKER_00: Just know that there are different nerves and branches, and the main player here is the infrapatellar branch of the saphenous nerve.
• 8:49
  SPEAKER_00: And that is the one that by far is the most common and it makes the most sense based on the anatomy and based on the incisions that are made in the ACL reconstruction surgery.
• 9:01
  SPEAKER_00: Now, one cool bonus about this episode is that I'm gonna plug in some pictures in the podcast notes.
• 9:07
  SPEAKER_00: So if you click the links, I promise they will take you to some pretty cool pictures that can help you get a visual of what's going on.
• 9:15
  SPEAKER_00: And you guys know I'm like super big on making things practical and so you can understand.
• 9:20
  SPEAKER_00: And I really feel like if you feel informed about what exactly is going on, man, then this can put your mind at ease and make it understanding to know, okay, why am I dealing with this?
• 9:31
  SPEAKER_00: What is going on?
• 9:32
  SPEAKER_00: And if you can visualize this, this will be a home run.
• 9:36
  SPEAKER_00: And this makes so much sense.
• 9:37
  SPEAKER_00: And even going through this for myself and digging a little deeper, I was like, wow, this makes so much sense.
• 9:44
  SPEAKER_00: And it was really cool to be able to help present this to you guys as well.
• 9:48
  SPEAKER_00: But when you look at this first picture, it's basically showing you a network of the nerves of the lower extremities.
• 9:54
  SPEAKER_00: So starting from the hip all the way down to the foot, and it's on the front side.
• 9:59
  SPEAKER_00: And what's really, really cool about this specific image is that it's actually highlighting what gets blocked when you get a femoral nerve block.
• 10:07
  SPEAKER_00: And so, for those of you who don't know, femoral nerve block is one of the regional anesthetics that you can get whenever you are having ACL surgery, and that can help to block the pain temporarily for you know 24 to 48 hours or so.
• 10:22
  SPEAKER_00: And this picture actually shows the pathway of those specific nerves.
• 10:27
  SPEAKER_00: And if you look at it, you can see basically on the front side you have your anterior femoral cutaneous nerve that's blocked with the femoral artery block.
• 10:35
  SPEAKER_00: There is the saffinous nerve that gets blocked with the femoral nerve block, and there is the infrapetellar branch of the saphenus nerve that gets blocked with the femoral nerve block.
• 10:45
  SPEAKER_00: But this goes to show you basically why it is that you don't feel nearly as much pain and what is getting blocked because those sensory nerves are having analgesa put into it to essentially block it for a little bit.
• 10:59
  SPEAKER_00: So this all makes sense.
• 11:01
  SPEAKER_00: And what I want you to key in on if you do look at it is where that infra patellar branch of the saphenus nerve goes.
• 11:08
  SPEAKER_00: So you'll see a very light, light green color, and that shows you it's basically at the front of the knee where the patellar tendon is.
• 11:16
  SPEAKER_00: But if you look at that little branch that it's connected to, that's it.
• 11:20
  SPEAKER_00: And so that makes so much sense of why people feel that numbness in that area.
• 11:26
  SPEAKER_00: And so, how does it happen?
• 11:28
  SPEAKER_00: So, with surgical techniques and with ACL reconstructive surgery, it's all going to really depend on the surgeon and the process as well as the graph types, the approach that they take, the incisions.
• 11:41
  SPEAKER_00: But in general, with ACL reconstructive surgery, it's an arthroscopy.
• 11:45
  SPEAKER_00: So that means it's minimally invasive, and they have these tiny little incisions where they stick scopes in and where they're gonna kind of operate out of.
• 11:55
  SPEAKER_00: And with this, one of the drawbacks is essentially that they're gonna make that small hole, which is gonna help with not having a big scar or a big incision to heal.
• 12:06
  SPEAKER_00: But the counterside of that is that they can't always see exactly what they are about to cut into and can't necessarily visualize every single structure that they're gonna make the incision for.
• 12:17
  SPEAKER_00: And so after an ACL reconstruction, there is numbness or tingling in those specific areas of the knee or even at the shin, and it is most likely due to damage to that infra patellar branch of the saphenus nerve.
• 12:34
  SPEAKER_00: This small nerve is easily missed by the surgeons, and it's almost hard to work around, especially with the specific types of surgeries, and one that we'll talk about with specific graph types like the hamstring tendon.
• 12:49
  SPEAKER_00: And so that's gonna be a key factor here.
• 12:52
  SPEAKER_00: But especially if this is gonna be performed via arthroscopy, it's gonna be tough to get around cutting through this nerve or even some parts of it, and numbness can come when that nerve is accidentally cut or stretched as they are getting into the knee itself.
• 13:10
  SPEAKER_00: And this leads to the second picture that you'll be able to look at, which basically shows this kind of highlight of the front of the knee and almost like these little tiny hairs of the branches of that inferior branch of the saphenus nerve, and it shows that it runs towards the front and the inside part of the knee, and then when this gets cut, you can almost imagine why people feel that palm size type of numbness, more to that front and inside part of the knee.
• 13:39
  SPEAKER_00: And almost like a good area to think about is where that button on the inside of the knee and where that screw goes, and that's typically an area that people will feel where there is that numbness or sensation after the surgery.
• 13:54
  SPEAKER_00: And so if you take a look at that picture, it shows like a wrist zone and it talks about just the different little branches and some of the incisions, and it'll help to depict what exactly they're trying to get with a safe zone.
• 14:07
  SPEAKER_00: But sometimes what happens, and especially with the way that nerves in our bodies work, is that it's not going to be perfect, but they're hoping to be accurate with most people.
• 14:16
  SPEAKER_00: But even based on that image, it is going to be nearly impossible for you to be able to dodge any of that nerve.
• 14:22
  SPEAKER_00: So some of it is likely to get impacted, whether it is cut or stretched in the surgical process.
• 14:29
  SPEAKER_00: And so, how common is it to have this numbness after ACL surgery?
• 14:34
  SPEAKER_00: When you read most of the research, it can range anywhere from 40% to almost 80-90% of people.
• 14:42
  SPEAKER_00: With most studies, I would say have a referencing point around actually 80%.
• 14:47
  SPEAKER_00: There was a study by Enderhog in 2014 where they looked at the impact of sensory deficits after harvesting hamstring autographs for ACL reconstruction.
• 14:58
  SPEAKER_00: 85% of the examined patients had sensory deficits.
• 15:02
  SPEAKER_00: And in another study by Sanders in 2007, this was research that found 74% of people who had numbness or tingling still felt this after six months after surgery.
• 15:15
  SPEAKER_00: 20% of those saw improvements after, and the improvements in these symptoms had a decrease mostly in the size of the area that has been affected within that year of ACL reconstruction.
• 15:27
  SPEAKER_00: And this is going to bring part one to an end.
• 15:30
  SPEAKER_00: And we're teeing up part two to understand okay, what are the graph types that play a role?
• 15:37
  SPEAKER_00: What's normal versus not, some of the anatomical variations, the nerve healing and regeneration, and what about the recovery of your numbness?
• 15:46
  SPEAKER_00: All this is coming in part two.
• 15:49
  SPEAKER_00: Wanted to set the stage here and help you gain understanding of especially the anatomy and understanding what exactly is going on initially in the process.
• 15:59
  SPEAKER_00: So then that way you can gain clarity on okay, this is what's happening.
• 16:04
  SPEAKER_00: Now, what can I do about this?
• 16:06
  SPEAKER_00: Or maybe not do, right?
• 16:08
  SPEAKER_00: And most importantly, feel informed so you know exactly all right, I'm feeling numbness.
• 16:13
  SPEAKER_00: Is this normal?
• 16:15
  SPEAKER_00: And also, what is the likelihood of me getting that back?
• 16:18
  SPEAKER_00: So tune in next week for part two.
• 16:21
  SPEAKER_00: And before I hop off here, if you guys have a second to spare, please leave the podcast a five-star review.
• 16:28
  SPEAKER_00: Helps us a ton, helps ACLers get the word, and that way they can know and be informed in this process, just like you.
• 16:37
  SPEAKER_00: It's so appreciated.
• 16:39
  SPEAKER_00: Love you guys.
• 16:40
  SPEAKER_00: I'll catch you next week.
• 16:41
  SPEAKER_00: This is your host, Robbie Patel, signing off.