A Comprehensive Guide to Musculoskeletal Injections

A Comprehensive Guide to Musculoskeletal Injections

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This article is the summation of 12 weeks worth of podcasts to give you (pretty much) everything you would need to know about getting an injection for an injury. Let's get started!


WHEN TO CONSIDER AN INJECTION (Episode 1+2)

When is an injection the right call?

So what are some situations where I would consider injection? Well, first and foremost, if you're in some pain or having some dysfunction, that's would be a pre-requisite. Number two is if you stall out with therapy, meaning you've tried physical therapy and you're not making any more progress. And number three, if you feel like you just need something a little extra to get you up out of your rehab rut. So you're not looking at this as a fix or a get out of jail free card, but rather a tool to help you get the results you want after you've been already putting in the hard work. A common analogy I use with patient is an analogy about a car stuck in the snow. When a car is stuck in the snow, the wheels are just spinning like crazy, but the car is going nowhere. The car is working hard, but it's just not making enough progress. However, if you get one of your friends to help push you out, all it takes is a little shove and then next thing you know, the car is out of the snow and back on the road. In this analogy, the car is physical therapy or home exercises, and injections are the friend that pushed the car out of the snow. The car is still doing the vast majority of the work, but it just needed a little push. So for an injury, you as the patient will do the vast majority of the work, but sometimes it can be helpful to get a little extra "push" from an injection to get you back on the right track.

Three reasons NOT to get an injection

First, if you just got hurt, I'm talking like within the last few weeks, it's probably not a good idea to get an injection. You're not a pro athlete, you don't need an injection immediately, just give it a little bit of time. Second, if you've done no therapy or do not plan on doing any therapy whatsoever, then I wouldn't recommend an injection. The third and final reason to not get an injection would be if you have not had all your options explained to you. We don't want to rush into anything, so it's important to take our time and understand all the risks and benefits.

What are the various injection options?

So you might be asking, well, what are my options? It's just a steroid injection, right? Wrong. There's lots of injection options that we have nowadays. I tend to put the various options into three main buckets: anti-inflammatory injections, viscosupplementation injections, and pro-inflammatory or regenerative medicine injections. Anti-inflammatory injections includes injections like steroids, but also medications like NSAIDs, which are non-steroidal anti-inflammatories. The main purpose of these injections is to decrease inflammation and calm things down. Next we have viscosupplementation, which that's just a fancy word for saying hyaluronic acid derivative injections. Your knee joint normally has hyaluronic acid in the synovial fluid and cartilage, and when we have conditions like arthritis, we have a decreased amount of hyaluronic acid in the joint, and so the idea is that we inject hyaluronic acid back into the knee to kind of give it some of the stuff that it's lacking. And finally, on the pro-inflammatory or regenerative medicine side, we have injections called dextrose prolotherapy, PRP or platelet-rich plasma and stem cell injections. The whole idea behind this category of injections is that we're re-stimulating your body's natural healing response. So we are actually trying to create inflammation in the area to recruit your body's natural healing factors to help you recover. It's essentially the opposite of the anti-inflammatory injections where they're trying to cool things down, and in these injections we are trying to purposely stir things up to restart that healing process.

Who should I see to get an injection?

And so maybe you're thinking, okay, who should I see for these injections? There are a couple of different options and they include orthopedic surgeons, non-operative sports medicine physicians, and primary care doctors. Most people know what surgeons and primary care doctors are, but most people probably don't know what a non-operative sports medicine specialist is. These are physicians who did a residency other than orthopedic surgery like family medicine or physical medicine and rehabilitation, and then went on to fellowship to specialize in musculoskeletal ultrasound and sports medicine. I'm a little biased because I am a non-operative sports medicine specialist, but in my opinion the best person to do an injection is someone who can do it under ultrasound guidance, or at least someone who does a lot of injections routinely.

Should I Get An Ultrasound Guided Injection?

You might be asking, why would I need ultrasound guided injection? Well the long story short is that ultrasound guided injections will have increased accuracy in almost every situation. For some injections you don't necessarily need the ultrasound, but when you do use the ultrasound, you're greatly improving the chances that the medication gets injected exactly where it should be. In fact, there have even been studies that show that orthopedic surgeons can struggle to get the medications into the joint if it's not the knee. It turns out surgeons are very good at finding the knee joint, but for other joints around the body, using an ultrasound will increase the odds of getting the medication into the right spot.

What do these injections cost?

So if you are still with me this far, then you are probably thinking about this pretty seriously, and I am sure you are wondering what these injections cost. That's a fair question. From a price perspective, some injections are crazy expensive and aren't covered by insurance. The injections that are typically not covered by insurance are injections like PRP, stem cells, and a lot of times, prolotherapy as well. Other injections like steroid injections or hyaluronic acid injections are typically covered by insurance, but you'll have to talk with your doctor and insurance company to figure out what is covered. Unfortunately, if you're interested in PRP or stem cells, those can cost thousands of dollars in some places, and so that's why I want to talk to you about all your options so that you are not making a rash decision and spending a lot of money on something that might not benefit you.

What are the risks of an injection?

Next, I want to talk about the general risks of any injection. Anytime I'm going to give an injection, I always talk about the risks and benefits so that the patient can make an informed decision. First from a risk perspective, I always talk about three really main things and these are the risk of pain, infection, or hitting an unintended structure with the needle. The first thing we talk about is pain. Unfortunately a needle is always going to feel like a needle, so there's no way of making the pain go completely away, as you'll always feel some needle stick. But honestly it's usually very tolerable and most people say it's not that bad when it's all said and done. The needle is usually pretty small, and the vast majority of patients do great, however we never know how each person will respond. Next we talk about the risk of an infection, which is something we don't mess around with. Anytime we break the skin, whether it is when we scrape our knee, or if we get an injection, we run the risk of something from outside our skin getting under our skin to where it doesn't belong. We always clean the skin, clean the ultrasound probe, and use sterile needles, but it still is a possibility we need to talk about. The odds of a joint infection happening are exceedingly rare, but it's something you have to counsel about and be aware of. Finally, we talk about the risk of hitting a nearby structure which could be a blood vessel or nerve. The great thing about ultrasound is that you can use it to see any large nerves or blood vessels, and can the purposely avoid them during your injection. However, it is possible that you don't see a small nerve or blood vessel (or it's too small to see on the ultrasound) and you could knick it, which could cause either some bleeding or nerve irritation. Both of these things are usually quickly handled and go away with either some pressure for bleeding, or just with time for nerve irritation, but it's always important to know that before getting an injection.

Who is the perfect injection candidate?

Let's talk about my perfect injection candidate. The perfect injection candidate is someone who's coming to see me who does not have a brand new injury and it has been going on for a little bit of time. Additionally, it would be ideal if they've been working hard on their rehab or their home therapy but maybe they've just stalled out with therapy at this time. Also this patient will understand that this injection will not fix them and they must be willing to put in more work to help them recover fully. Finally, at the end of the day, they also have to understand the risks and benefits of the injection. Obviously every patient is different, and nobody is ever going to be a "perfect" candidate. However, I hope this gives you a framework of what to think about, and serves as a conversation starter for you when you are talking with your healthcare provider.

If you want to go even deeper, watch the podcasts associated to these questions.

Episode 1

Episode 2


ARE INJECTIONS BAD FOR YOUR CARTILAGE? (Episode 3)

What does chondrotoxic mean? What are some substances that are chondrotoxic?

The two root words in chondrotoxic are chondro (meaning cartilage) and toxic (meaning harmful), so it means something that is harmful to the cartilage. Unfortunately, it seems that a few of our common injections can potentially be chondrotoxic, so this is important to know that when choosing an injection. I should first clarify and say that all of this data is based off of petri dish mechanistic studies, and other less rigorous studies, and there are only a few of these papers published, so the data is not robust.

First let's start off with the ones we know to be chondrotoxic, and these are steroids and local anesthetics. These two seem to be the most studied, and the data makes us believe that they can be chondrotoxic. This does not mean that one injection is going to ruin your cartilage. In fact, we do not have any data to support that claim, but repeated injections into the same joint do cause us concern that it could lead to accelerated breakdown of cartilage over time. When it comes to steroids, the worst offending agent seems to be betamethasone, with triamcinolone and dexamethasone looking like better options. In terms of local anesthetics, it seems that the worst one is lidocaine, followed by bupivacaine, then with ropivacaine being the least chondrotoxic.

Next let's talk about our NSAID injections (ketorolac). There is very little data on this, but the one paper that I have seen does show some mechanistic plausibility that is may be chondrotoxic. So, because we have such little data, we are relying on a mechanism and our clinical experience to say that we think it MAY not be quite as chondrotoxic as steroids. However, we cannot say that with confidence.

In terms of viscosupplementation, prolotherapy, and PRP, those do not appear to be chondrotoxic.

So, if we are looking for a diagnostic injection that will give us the (theoretical) least amount of damage to the chondrocytes, I would probably use a mix of an NSAID and ropivacaine. If we are looking for an alternative injection that has no chondrotoxicity (that we know of), then we could use dextrose prolotherapy mixed with normal saline, viscosupplementation, or PRP.

Once again, I am not using this to try and scare you, and in fact I do think it is reasonable to try a single injection for diagnostic or therapeutic purposes. However, I just want you to have this information so you can make the more informed decision about your treatment options.

If you want to go even deeper, watch the podcast associated to these questions.


VISCOSUPPLEMENTATION INJECTIONS (Episode 4)

What is the mechanism behind visco-supplementation?

Viscosupplementation, or hyaluronic acid derivative injections are a unique category of injections. They aren't anti-inflammatory like steroids or NSAIDs, and they don't fall under the pro-inflammatory injections like prolotherapy or PRP. Hyaluronic acid is a main component of cartilage and synovial fluid, and it helps give cartilage its viscoelastic properties, and helps lubricate the joint. So, when we inject viscosupplementation, we are trying to "give back" some of the building blocks that your joint naturally has. In fact, we tend to see a disruption of the quantity and quality of hyaluronic acid inside arthritic joints, so the underlying idea is to give some "help" to those joints by providing some necessary components we know they are lacking. Now, the injection does not last very long inside the joint (a few days max), but the injections may play a role in decreasing inflammation, helping cell growth, and decrease pain by masking joint nociceptors. So, even though we aren't entirely sure why it works, this is what the proposed mechanism is.

What are the different types of viscosupplementation?

There are a bunch of different types of viscosupplementation brands, but they basically fall into two categories: low or high molecular weight. Lower molecular weight hyaluronic acid injections typically are dosed where you receive a series of injections, usually spaced about a week a part. For example, you would get an injection in your knee, then come back each week for 2-3 more weeks to complete the "series." The higher molecular weight injections are typically a single injection, as it is thought that the higher molecular weight may take longer to break down, and it stays in the joint a bit longer. Overall though, there is not a lot of great data that one category of visco works better, so I typically go with a single injection because it is more convenient for everybody.

When should you consider this injection?

The main use case for these injections is for osteoarthritis. There have been studies looking at all sorts of joints like the ankle, knee, hip, and hand, but the majority of the data is for knee osteoarthritis. Overall, the results are mixed when looking at the literature. However, the overall trend seems to point in the direction of it being beneficial, but only in select patients. Who are the ideal patients for this? Well, it seems that the best candidate for this injection is someone who has mild-moderate osteoarthritis. It just doesn't seem to be as efficacious in those with severe arthritis. Additionally, it's worth mentioning that it doesn't seem to be chondrotoxic, so this is our first "joint preserving" injection that we have talked about so far. Personally, I have started to use this more in my practice for earlier OA patients and have had good success. That being said, some insurances won't cover this, so be aware of that before getting the shot.

If you want to go even deeper, watch the podcast associated to these questions.


STEROID INJECTIONS (Episode 5)

How do steroid injections work?

Steroids are the gold standard for anti-inflammatory medications. In fact, our other class of anti-inflammatory medications are called NON-steroidal anti inflammatory drugs (NSAIDs). Once they get into the body, the bind to a receptor inside the cell, and this complex then moves to the nucleus where it can start going through the process making proteins and start to have an effect. That being said, you can see that it is kind of an involved process, so we typically don't start to see any effects from the steroid for a couple of days up to even a few weeks. Once it starts working, it begins to inhibit the accumulation of inflammatory cells and mediators like leukotrienes and prostaglandins, but it also has some immunosuppressive (weakens the immune system) effects as well, so it really affects a lot of systems. Essentially I think of a steroid injection as shutting off the water main when there is a problem... it just shuts down everything.

What are the side effects of steroid injections?

Steroids have some specific side effects that I like to talk about. The first one I always talk about is that steroids can be chondrotoxic which means they can potentially damage the cartilage in your joint. That's obviously a big consideration and it's always something I have to counsel patients on is that this steroid could be doing some long-lasting damage to your cartilage. On top of that, steroids may temporarily increase blood sugar in those people with diabetes which could lead to them having some trouble controlling their blood sugars. Also, anytime we inject a steroid you can have something called a steroid flare, which is where you have a paradoxical increase in pain the next day or so, but that's usually short lived. Finally, I always talk about you can have some thinning of the skin from the injection, and if you have darker pigmented skin you might have lightening of that skin if you inject it close to the top of that skin.

What conditions are steroid injections used for?

Steroids will be used for all sorts of situations... but the real question is whether or not they SHOULD be used in all those situations. The most common reason people get steroid injections is for arthritis. But we have to go back to once again, if we're injecting for arthritis, are we making it worse long term with a steroid injection? That's up for debate. However, it does typically offer a nice bit of pain relief in this condition, but that is only temporary until the medication wears off. In terms of using steroid injections for tendon issues, that is usually just not a great option. I've mentioned how the steroids may decrease the cartilage inside the joint, well they can also weaken your tendons. So injecting something into a tendon to make it weaker sounds like a recipe for disaster to me. So typically if patients are coming in with a tendon issue, I don't inject them with a steroid. However, there are a few conditions for which I think a steroid injection can be really helpful and those are trigger fingers, or DeQuervain's tenosynovitis in your wrist. Those are ones that I will still use steroid injections for as a first line treatment because they can potentially be curative (meaning they don't have to get another injection). However, those aren't the only things I use steroid for because some people prioritize immediate pain relief, and so we have to take that into consideration when deciding on what to do.

If you want to go even deeper, watch the podcast associated to these questions.


NON-STEROIDAL ANTI-INFLAMMATORY DRUGS (NSAIDs) INJECTIONS (Episode 6)

How does an NSAIDs injection work?

NSAIDs are NON-steroidal medications, so they work in a different pathway than steroids, however they are still considered an anti-inflammatory injection. NSAIDs prevent the conversion of arachadonic acid to inflammatory mediators like prostaglandins, prostacyclins, and thrombaxanes and they do this by inhibiting the cyclooxygenase pathway (COX).

Are NSAIDs chondrotoxic like steroids?

There is not nearly as much data on NSAIDs than there is for steroids, so this still isn't as well known. I was able to locate one study which showed that a single dose of toradol did show significant in vitro chondrotoxicity, but this was just in a petri dish and not in human subjects. So, we can't say definitively if it is less chondrotoxic than steroids, because we just don't have the data, but the thought is that it MIGHT be less chondrotoxic because it doesn't affect as many pathways as steroids do.

When would you use this type of injection?

In reality, there is not a whole lot of data on these type of injections, but most of the studies are related to either knee OA or shoulder pain. That being said, mechanistically, we can use these injections anywhere we would use a steroid injection. Other areas that I have seen data on include hip osteoarthritis, and trigger finger in the hand. That being said, there is no FDA approved use for ketorolac for any kind of joint injection, so we are technically using this off label when we do use it. I specifically use this injection as a "less bad" option potentially. If I have a patient who can't get a steroid shot for some reason, then I would definitely try this. Additionally, we are unsure of the true chondrotoxicity of the NSAIDs, whereas we know steroids are chondrotoxic, so another use case might be trying it in someone who we really want to be as careful as possible in sparring their cartilage, but who still wants an anti-inflammatory injection. Once again though, this is just speculation without solid data.

What are the potential side effects?

All the other side effects still apply to this injection, but on top of that I would not use these injections in anybody who has a history of bleeding, kidney issues, ulcers, or heart problems as NSAIDs are known to be a problem in these patient populations.

If you want to go even deeper, watch the podcast associated to these questions.


(DEXTROSE) PROLOTHERAPY INJECTIONS (Episode 7)

What are prolotherapy injections, and how do they work?

Prolotherapy injections are a type of injections that are performed with the intention of creating inflammation in a certain spot to try and re-stimulate your body's natural healing response. This can be done using multiple medications, but the majority of the data is on dextrose (sugar) injections. The definitive mechanism is unclear (and up for debate), but it is thought to cause chemical trauma with the dextrose that leads to a change in the osmotic gradient in the cells which creates inflammation in the area and then recruits cytokines and activates various types of cells (fibroblasts, chondrocytes, nerve cells). On top of that, we are causing mechanical trauma with the needle, and this may also release additional healing factors in conjunction with the chemical irritant. Finally, it's worth mentioning that these injection can leave patients quite sore for a few days after the injection. After all we are literally trying to create inflammation, so don't be surprised if you are sore... because that is the goal!

How is the medication given?

The most common procedure is using a 25% dextrose solution, and that is done by mixing a 1:1 ratio of 50% dextrose with some other agent (lidocaine, ropivacaine, normal saline, etc...). They have found that if the concentration is about 12.5% then it tends to have a pro-inflammatory response, whereas when it is under 10%, the inflammatory response does not seem to happen.

When we do dextrose prolotherapy injections, there are a couple of ways we can do the injection. First, we can do just a normal injection like any other injection where we just push the liquid into the desired area. However, the most common way we do this injection is to do something called a needle tenotomy, which is what we commonly due when we are dealing with tendon problems like jumper's knee or tennis elbow. With a needle tenotomy, we use an ultrasound to take a look at the tendon and then use the ultrasound to guide the needle into the location of the injury where we inject the prolotherapy. Additionally, often times the person doing the injection will do multiple passes of the needle in the tendon, a technique we call fenestration, to add some mechanical trauma to the area to help create more inflammation. Most people will commonly mix the dextrose with lidocaine, so once we get into that tendon, we spray some of the mixture in there and it should lessen the pain of the injection. Additionally, it's worth mentioning that these injections are commonly done in a series. So we will typically do an injection, then bring a patient back in about 3-6 weeks and repeat the injection for a total of 2-3 or more times. The idea behind this is that we trigger a big healing response, then as your body starts to finally calm down and slow down the healing process, we re-trigger that healing response. Once again, this is not a perfect science, but we are trying combine the laboratory data we see with clinical outcomes to help patients the best we can.

What type of conditions can this be used for?

The two big conditions that these injections are used for are tendon issues and arthritis. There is probably more data on tendons than arthritis, but I think both conditions are very reasonable to try these injections for. When I say tendon issues I am talking about areas like the achilles tendon, elbows, rotator cuff, and also the plantar fascia. And although there isn't the biggest data set in the world on these injections, I feel really good about using these in various conditions because of how safe of an injection it is. I've talked about how steroid injections may cause damage to the cartilage, and it seems like that isn't the case with these injections, and in fact they may actually create a more beneficial environment in a joint that has arthritis. Once again, all the same risks of any injection still are possible, like pain, bleeding, and infection, but overall because we are just injection some sugar water and maybe some normal saline or lidocaine, we consider it a super safe injection.

If you want to go even deeper, watch the podcast associated to these questions.


PLATELET RICH PLASMA (PRP) INJECTIONS (Episode 8)

How does a PRP injection work?

Platelet Rich Plasma, or PRP is a type of injection that is used for lots of common ailments like arthritis, tendon issues, or other sports medicine conditions. What makes a PRP injection unique is that the substance that is actually injected are components that are taken from your own blood. For this procedure we typically draw some blood from you, then place it in a centrifuge and spin it in there from anywhere between 5-30 minutes until we get separation of different cell layers like your plasma, red blood cells, and your platelets and white blood cells. Then, some of the plasma and the highly concentrated platelets are extracted and used for the injection.

Now why do we care about concentrating platelets? Well, it turns out that platelets, although super small, contain a lot of very useful things inside of them. The most important thing they have are growth factors that can help with the healing process of multiple injuries, so essentially we are trying to give an injured area of your body a jump start to their own process of repair and healing.

Do PRP injections actually work?

Well, that answer is not so clear. There are TONS of studies looking at PRP, but there is a lot of mixed results from the studies with some showing benefit, and others showing no benefit when compared to other injections. One of the reasons this may be the case is because there is no one standardized 'dose' of PRP. Every manufacturer of PRP machines makes a slightly different concentration after their spinning cycle, so it's really hard to compare results between patients because they could be getting drastically different concentrations of PRP. Also, every person is unique, and it's possible that their platelet concentrations might be abnormal or different from somebody else, and that could skew the results. That being said, there are plenty of studies showing improvement in pain and functional outcomes with conditions like arthritis and tendon issues, and overall these injections tend to be very safe injections.

What should I consider before getting one of these injections?

There are a couple of downsides that you should consider before getting a PRP injection. First, there is no guarantee that you will respond to this. Just like every other injection out there, we never know how anybody is going to react to this injection. Second, some people feels that NSAID medications might interfere with the platelets and therefore don't recommend taking them after the injection, and that can be quite the frustration as these injection can be quite irritating. Third, it can be inconvenient as this injection does take some time to prepare, so you may be sitting at your doctor's office for about an hour while the platelets are being prepared. Fourth, depending on where you get the injection, it may take you out of commission for a few weeks. If you do a PRP injection into a tendon, the typical recommendations are that you offload that area for a few weeks due to the risk of tendon rupture if you are too aggressive, too soon. So, you just need to know that in case you had something you needed to do right after the injection, so you can plan accordingly. And finally, we have to talk about the elephant in the room which is the cost. On average these injections run between 500-1500 dollars, depending on where you live in the country. That's an insane amount of money, and odds are that your insurance won't cover it at all. I can't think of many more frustrating things than to pay a ton of money for something and get zero improvement, which is a possibility with these injections.

How do you counsel patients on PRP injections?

First, I typically don't recommend this if you have tried nothing else. If you have done no rehab whatsoever, and don't plan to do any for the pain you have, then this probably isn't a good fit for you as we tend to have the best results with patients who are also working hard in therapy in addition to the injection. Second, it depends on the condition for which they are seeing me. The best data for PRP seems to be in tennis elbow and knee osteoarthritis, and although it can be used for a bunch of other things, those would be the two where I feel more confident in these injections. Third, before getting a PRP injection, I would personally offer them a prolotherapy injection because it is typically a fraction of the price. That being said, prolotherapy is not that common of an injection, but if you search for it I'm sure you will find providers who can do it.

If you want to go even deeper, watch the podcast associated to these questions.


POST PROLO/PRP PROTOCOLS (Episode 9)

Are prolotherapy and PRP recovery similar to other injections?

It's important to know that the recovery from a PRP or prolotherapy is a little different than the other injections. First of all, these are pro-inflammatory injections, so you are going to feel it for the next couple of days. That's normal. It's just important you know that going into it so you don't get worried when you are sore for a few days after. That will pass with time, but just be cautious. Additionally, (although there is debate on this) some people think that you shouldn't take NSAIDs after getting these injections because they might decrease the inflammation which may limit the effect of the injection. I typically tell my patients to try and avoid them if possible, but it's really based on clinical experience and not solid evidence. Finally, if you get a tendon injection, then your recovery will look quite different. When we inject into a tendon, we typically also do a fenestration as well (moving the needle in and out of the tendon) to create mechanical stress. When we do this inside a tendon, it temporarily weakens the tendon and leaves it (theoretically) susceptible to rupture easier. So, we will typically recommend that the patient off-loads the area for a bit to let it recover. Overall, the general consensus is that when there should be about a two week limitation of activity after the injection. What this means is that we aren't intentionally exercising or loading that area for those two weeks, then we start back our strengthening. It seems to be ok to start range of motion exercises after a few days, but we typically wait to do proper loading for two weeks. That being said, a lot of this is consensus based with no hard evidence, so it is just expert opinion and every person may have a different recovery course.

If you want to go even deeper, watch the podcast associated to these questions.


STEM CELL INJECTION (Episode 10)

What are stem cell injections?

Stem cells are a type of non-specialized cells, meaning that they can become multiple different types of cells. They have the capability of self renewal, and can become different cells like osteoblasts (bone cells), chondrocytes (cartilage cells), tenocytes (tendon cells), nerves, and a bunch of other things. So, the idea is that if we inject them into a problem area, we are giving that area additional resources to "regenerate" the tissues in that area. That being said, there is no real evidence that there is any sort of regeneration actually happening in the joint, and that is a common misconception with these injections.

Where do you get the stem cells from?

In the US you cannot use any embryonic or fetal derived stem cells (cells from a fetus or umbilical cord or placenta). The stem cells that are used for musculoskeletal purposes typically come from either your bone marrow, or adipose tissue. These procedures are more involved compared to any other injection (even PRP), and often times require sedation as the harvesting procedures can be quite extensive. Once the cells are harvested, then are spun down in a centrifuge to concentrate and purify the stem cells for injection.

Do stem cells actually work?

Unfortunately, we run into the same problem we had with PRP in that we do not have a lot of solid data for stem cell injections. Just like PRP, there is a ton of variability in the preparations of these injections, so it's really hard to get a definitive answer. That being said, the main use-cases for this seem to be arthritis and tendon related issues. The data seems to show that stem cells may help pain relief longer than PRP, but once again there is mixed data. That being said, I can confidently say that it is not some "magic injection" that works 100% of the time for everybody like I've seen people advertise. Just like PRP, some people get amazing results, while others don't get any improvement. It's frustrating we can't predict this, but this is the unfortunate reality at this time.

Should I get a stem cell injection?

Stem cells are truly a new frontier right now. Personally I am really excited to see where they go in the future because they definitely have some interesting potential. That being said, I typically don't recommend stem cell injections (I don't even perform them) to my patients for a few reasons. First, the data is just not a slam dunk for this and I would much rather start with prolotherapy or PRP. Second, we don't really know the long term risk of these injections. It seems safe in the short term, but there isn't really any long term data on these injections and that is something I would like to see more of. Third, I just can't in good conscience recommend these injection because they are insanely expensive. These typically run between $2000-5000, and unless you are Scrooge McDuck, I just can't justify these injections for the cost.

Is there anything else I should know?

Yes. If you have had a history of cancer then it is recommended that you do not get a stem cell injection due to the theoretical risk of uncontrolled growth of the stem cells.

If you want to go even deeper, watch the podcast associated to these questions.


HYDRODISSECTION INJECTIONS (Episode 11)

What are hydrodissection injections?

Let's break down the word hydrodissection: hydro-meaning water, and dissection- meaning to separate. So, we are using fluid to help separate something. That's pretty much it. Typically with this injection the most common reason we do it is to try and alleviate a nerve entrapment/irritation at some specific point.

How are these done?

Unlike the other injections that can be technically be done via a landmark fashion, this injection NEEDS ultrasound guidance. What we do is we find the target tissue/nerve with the ultrasound, then we introduce the needle under the skin while watching the needle tip the whole time under direct ultrasound visualization. Once the target is identified, we inject the solution around that area in an attempt to "release" the nerve from the area where it was entrapped or being irritated.

What is injected?

Various solutions can be injected including steroids, local anesthetics, dextrose, normal saline, and PRP. That being said, typically there is some mixture that is used for these injections. For my personal practice, I typically use a little bit of dextrose (< 10% concentration so it isn't pro-inflammatory) with normal saline. Dextrose can actually show some analgesic properties at lower concentrations, so I like to use this because we know it is safe and well tolerated.

When should I consider this injection?

Like I mentioned previously, the vast majority of the times I do this injection it is for a nerve release. The most common use cases are for carpal or cubital tunnel, with carpal tunnel being by far the most popular. Additionally, these can be used to separate a tendon from a fat pad, like around the patellar and achilles tendon. I would generally recommend these injections to patients who have not had an adequate response from physical therapy, and have tried other conservative modalities first.

What are some other considerations?

First, there are some unique side effects from these injections since we are typically injecting right around nerves. There is a chance that you could damage the nerve with the needle and that could create some neuropathy after the injection. Usually this will still go away after a little bit of time, but it can be really scary and frustrating, so it's something I always counsel about. However, overall these are really safe injection that I think are a reasonable thing to try.

Another specific use case is when using it to dissect the fat pad away from a tendon, we can do this in an in-season athlete. If we did a prolotherapy or PRP injection in an athlete who is currently competing or training for something, we would have to shut them down for a while to off load it. This isn't the case with a hydrodissection, as we usually only need to restrict them for a few days at most before they can go back to play. This is because we actually never pierce the tendon with these injections, so there shouldn't be any trauma to the tendon.

If you want to go even deeper, watch the podcast associated to these questions.


BOTULINUM TOXIN INJECTIONS (Episode 12)

Wait... isn't this just used for cosmetic reasons?

The vast majority of the time botulinum toxin injections are either for cosmetic reasons or for migraines, but we can use them from time to time for musculoskeletal reasons. Botulinum toxin is a toxin that is produced from a bacteria that acts on motor and sensory neurons and produces weakness at the neuromuscular junction. In laymen's terms, it decreases the ability of the muscles to contract.

When is this used is Sports Medicine?

This is definitely a fringe use case, and this is definitely not a common one. Additionally, this is not going to be covered by insurance, so it will be expensive. However, a few of the conditions that it can be used for are chronic exertional compartment syndrome, plantar fasciopathy, osteoarthritis, lateral epicondylopathy (tennis elbow), myofascial pain syndrome, and piriformis syndrome. There is VERY little literature on this, so this truly is a "special occasion" type of injection because we just don't have any data saying how affective this is.

If you want to go even deeper, watch the podcast associated to these questions.


References

If you read that and still have concerns or questions, you may enjoy listening to the entire third season the Building Lifelong Athletes Podcast which dives into all of these injections in more depth. Additionally, if you are a nerd like me and want the references, they are attached below!