• LecturehallWriting Orthotics Prescriptions
  • Lecture Transcript
  • TAPE STARTS – [00:00]

    Male Speaker: Our next speaker is Scott Marshall. Scott, as you may know, is involved in the orthotic business both custom and over-the-counter, also in the area of ankle foot type of orthotics. He has been in the business for probably 40 something years, which makes him an expert. And at this point, we are going to ask Scott to talk about writing orthotic prescription. So please welcome, Scott Marshall.


    Scott Marshall: Thank you. So here is our three learning objectives for our CME requirement. I'm not going to go through them in detail and here is my disclosure of information because I'm an owner of KLM Labs and so let's get started. So there are literally probably over 100 orthotic labs out there that can service your orthotic needs and we all really make a lot of very similar products. We all use the same materials. From any of us, you can order by a specific medical condition, for example plantar fascitis, hallux abductovalgus, hallux rigidus or you can order by a specific application like running, football, basketball, baseball, soccer, anything you can name. And so this is really the easy part. From any lab, you can write down an application or medical condition. They will make you an orthotic but what separates you, the podiatric medical specialist from everybody else out there posting or make you get prescribing foot orthotics is you're the only ones with a comprehensive understanding of foot function and the ability to integrate surgical orthotic and pedorthic care as required to maximize a particular patient's benefit.


    In fact, this ability to take an orthotic and modify a lab's basic design to meet the needs of a specific patient is innate to the field of podiatry. You are the only ones that do it and believe me I deal with all the specialties. So my goal is to really get you to understand the why behind the what today when you are modifying an orthotic prescription and I'm going to talk about all these areas of control both on the positive model or even if that positive model's in a computer or in the orthotic shell itself and I will start with heel and work my way through the arches and finish with the forefoot area. And so I want to start by talking about heel cup height. Now most labs use gender and shoe style to determine the heel cup height of their orthotic. Typically, most men have a 12 heel cup and women have 10 and the reason for this is because women tend to wear more tight fitting, more fashionable, more close fitting shoes. And so the higher you have the heel cup, the wider the orthotic, the harder for it to fit into a tight fitting shoe. In contrast to this, sports orthotics is typically like 16mm because we have a lot more room in a running shoe or sports shoe that has removable insole. So what you need to understand is how your lab measures it. Some of us measure it on the inside and some of us measure it on the outside. And so in this lower diagram, we got 4mm shell, 12mm on the inside and 16 on the outside. And so if you wanted 16 on the inside and your lab is measuring it on the outside, you're not going to get as controlling of the device. And so you really need to know a lot about how your lab does things to make sure that you get what you want when you are modifying your order.


    You can always have the lab plantar grind to heel and that will keep the inside and outside relatively the same. Couple of little pearls. The higher the heel cup, the more controlling the device and the stiffer the shell. And the reason for it's more controlling is because you have more contour that the orthotic is touching on the foot. The more contour, the more control. Likewise, it creates a stiffer shell because where transitions into the lateral and medial arches, you have a lot more curvature. So that curvature creates a stiffer product. You want to increase the medial heel cup to resist pronation and you want to increase the lateral heel cup to resist supination. Rear foot posts are also very common, extrinsic, added to the heel, used to slow or control pronation during the early stance phase of gait from heel contact. It's also an excellent modification for your patients that have a low subtalar joint axis or whenever you have got significant subtalar joint motion in the frontal plane, usually made from hard rubber or high durometer EVA. Durometer is a measure of density and the stiffness of the material, so the higher the durometer, the less it will compress. Most orthotics come stand with the rearfoot post, especially all your sports and functional type devices and your standards 4 degrees of inversion with no motion ground into the material, EVA and the pronation is controlled or resisted again through that durometer measurement of that material. And you can order different durometers in your rearfoot post. You can order more or less depending on the patient's need. For example, if you have got a runner who is a rapid pronator, you may want to put a 6-degree inverted post on it. Or if you have got a patient who is a lateral ankle sprainer, you may want to put a 0-degree or may be 1 or 2 everted post on their in order to control and prevent that lateral supinatory moment at heel contact.


    You just want to remember that you are adding material under the heel of the orthotic and so you are going to be lifting that heel up in the shoe. The more you invert or evert it, the more you are going to lift the orthotic up so you can create shoe fit problems. Now you can have the lab actually grind in the motion. So 4 degrees of inversion with 4 degrees of motion. This will certainly help for the raising of the heel but no matter how you slice it when you add anything to the bottom of the orthotic, you are going to lift it up in the shoe and shoe fit is a critical issue for your patient's compliance. You can also add flares to rearfoot post and so typically we do this to increase the area of control. So here it's inflare. This is the standard way that we would do a rearfoot post. And so when we add the phalanges, you can see how much it increases the surface area. Medial flares really help delay not only the speed but the extent of heel contact pronation during early stance phase and they really help stabilize the subtalar joint. Lateral flares are excellent for your lateral ankle sprainers or anybody that has lateral instability. Again, you are adding more material, so you can create a shoe fit problem. You could also add heel lifts to any of your rearfoot post, typically used for a limb length discrepancy but this is an excellent modification for your patients who have osseous equinus or forefoot equinus.


    Normally, you can get about up to 6mm of lift before you lift them out of the shoe but if they are wearing extra depth shoes or they have removable insoles, you can actually put more in, maybe up to 8 to 10. And if they have removable insoles, it's a limb length discrepancy, you want to try and raise the entire plane of the foot together not just the heel. Medial skives created additional resistance to pronation at heel contact and into early mid stance, very similar to a rearfoot post. In fact, there are some studies out there that suggest that a medial skive is actually as good if not better than a rearfoot post and what's nice about the skives is that they don't fill up the heel counter of the shoe. And this is created by taking an area of the positive or on the orthotic itself and carving a flat spot almost like you were taking a tangent of that surface. And what it does is you could see the parabola on this side. On the other side, where it says skive, you could see the flat area that's going to push up on the medial aspect of the calcaneus resisting pronation, providing a supinatory moment and it's usually ordered in 2mm increments, 2mm being the least amount of resistance and 6mm being the maximum amount of resistance. With your rapid pronators, it's really great to combine these techniques. So a rapid pronator, we would like to do a medial skive plus medial heel cup plus medial flare on the post. Lateral skive is the same story. We are going to create that flat spot on the orthotic so to push up laterally on the calcaneus everting and pronating it providing a pronatory moment at heel contact and again with patient's with lateral ankle instability, they really benefit by combining the technique.


    Lateral skive, deep lateral heel cup and lateral flare on the post. You can also have padding to any of these, typically add the padding if you got a sore tender areas on the heel or especially if you are looking to off load a painful area with a doughnut pad or a horse shoe pad, for example for plantar fascitis or maybe a heel spur. You can normally get about 3mm. We don't like to do more than that because again you are lifting the heel off the orthotic in the shoe. Let's look at the medial arch. Now the purpose of this medial arch fill correction is to flare the medial edge of the orthotic away from the natural contour of the foot to allow some flattening of the arch, but you can order more or less depending on the patient's need. For example, if you want to order more fill, put more material in here than normal, you are going to lower the arch on the orthotic, which means the patient is going to pronate on it a little more. It's going to be a little more forgiving. Excellent modification for your elderly patients or your more obese patients that you are afraid they will not be able to tolerate the additional correction. Or you can go to a minimal arch fill, which is going to be a much more tighter close fitting device with the higher arch, stiffer orthotic and a more controlling device. Excellent option for your younger patients or your more serious athletes. Also by ordering less medial arch fill and a higher heel cup, you are going to get a stiffer device, so you can quite often use a thinner plastic or composite plate and get the same stiffness. Or by ordering more medial arch fill and a lower heel cup, you are going to have much more forgiving device, again probably for your elderly patient or your more obese patients.


    Plantar arch fills are typically added in sports applications where you want flexible shell but you don't want it to bottom out and the stiffness of that device is going to be determined again by that durometer of the plantar fill material. So here you have got about 60 to 65 durometer material. That's going to be a fairly stiff flexible device. I'd use something like this on a stop start sport like tennis or basketball. Over here we are using Poron which is probably like 20 durometer. So it's going to be a much more forgiving flexible device, maybe for elderly patient that's walking a lot or aerobic situations, stuff like that. And again, you just want to remember you are adding bulk on the plantar surface of that orthotics, so I would not add plantar arch fills unless you do have a removable insole. You can also add medial phalanges to any orthotic. This is done to increase the stiffness and pronation control. What the lab does is they are going to round up the medial aspect of that correction so the orthotic will wrap up underneath the talonavicular area, again contouring more of the foot giving you a more controlling device. Problem with phalanges is they are not tolerated well by a lot of your adult patients and they don't fit well in a lot of adult shoes but this is an excellent modification for your pediatric patients and this is why it's an integral part of your typical UCBL. Fascial band accommodations are added when you have patients with flexible anterior cavus, which causes the plantar fascia to bowstring at heel off.


    And so to test for this, it's very easy, you just dorsiflex the hallux and looking at medial arch and if you see the bowstringing, you want to mark it. Make sure it's marked in your cast or in your digital scan so that the lab can see exactly where it is. They will put a little ridge of material there and they will create a groove for that plantar fascia to bowstring into while still maintaining the integrity of the controlling part of the arch. Alright, let's go to the lateral side. So the lateral arch correction, we're doing this to accommodate for fat pad expansion during gait on the heel and lateral border of the foot. So obviously, this is typically only used with a nonweightbearing cast. What you need to do is you need to really look at your patients and see if they have a lot of excess fat tissue or lack of tissue tone especially in the heel area. So if you have a lack of tissue tone, you are going to want to order a minimal amount of lateral arch expansion correction. If you have got excess, you are going to want to add the maximum amount. Styloid process accommodations are added when patients have a large styloid process right at the base of that fifth and that could quite often cause irritation. So what the lab will do is again the will round up the lateral aspect and they will also add plantar to it so that we get a nice little pocket for that styloid process to fit into and lot of practitioners will have it filled the foam just to make it that much more comfortable. But this is an excellent modification for your patients that want to subluxate that lateral column at heel off. Again, we are making a pocket for that to fit in too comfortably while maintaining the integrity of the orthotic. Lateral phalanges are added to prevent the foot from sliding laterally off the orthosis.


    Again, we do the same thing. We are rounding up at lateral border so that that phalange can wrap up around the cuboid and the base of the fifth met. Excellent modification for patients with increased transverse compensating the mid tarsal joints are really whenever you are looking for increased medial lateral control during mid stance. Like medial phalanges often not tolerated well by adults and quite often don't fit well in their shoes but again excellent modification for your pediatric for your younger adults and again that's why it's an integral part of your standard UCBL. Now all labs put about 3mm of transverse arch support in the shell of the orthotic but a lot of practitioners like to add additional met pads to further not only pad the metatarsal head 2, 3 and 4 but to lift them and give you a little more support. This is an excellent way to engage the windlass mechanism and typically most labs will have 3, 4 and 5 different sizes, so you just tell him what size you want, how high you want it and whether you want the soft or a firm material. Met bars, same purpose, only it lifts and cushions all the met heads. Again, excellent for engaging the windlass mechanism and you just need to tell the lab how thick to make it, how high to make it and whether you want it in softer firm materials. Neuroma pads are added to lift and separate metatarsal heads and prevent them from putting pressure on a nerve or scar tissue or maybe some other puncture injury something like that. You just tell the lab, which interspace to put it in, 2-3 or 3-4 and how high you want it and again how soft or firm that you do want it. So it's really important for you to know your labs variables. What materials they have, how soft or firm they are. Very important.


    You also want to remember that met pads, met bars and neuroma pads are going to lift the met heads in the toe box of the shoe. So you really got to consider the height of them in terms of what kind of shoe you are putting it into. If it's into a shoe with a removable insole, much easier to put a nice big pad in there. Alright, let's look at the forefoot. So the most common modification we see is forefoot accommodations to offload any sore tender area anywhere on the foot and typically what the lab will do if it's on the forefoot is they will extend, put an extension on it and then they will cut a pad and put it on top where they will cut out the area to be offloaded. So here we are offloading one. Here we are offloading two and in addition a lot of practitioners like to combine it with a met pad to further lift that metatarsal proximal to the area to be offloaded. Key is you want to make sure that you have got the cast or your scan or in a photograph you have it marked clearly so that the lab can place it where it needs to be and it really needs to show you also the size because we definitely don't want it too large and we definitely don't want it too small. Morton's extensions are indicated for the patients with a structural elevatus of the first ray. That is when that second met head is bearing weight excessively and the first cannot plantarflex in late mid stance and propulsion. It preloads the first met and the hallux and balances that load on the second through the fifth met heads. This is an excellent modification for patients with hallux rigidus or limitus or really whenever motion at the first metatarsal phalangeal joint is not desired. The opposite of this is what they call a dancer's pad or some people call it kinetic wedge.


    Basically, this is the same as the first met head accommodation but its goal is to lift 2 through 5 and create a pocket for the first to plantarflex down and function below the other met heads. This is an excellent modification for functional hallux limitus or whatever plantar repositioning on that first ray enables first metatarsal phalangeal joint dorsiflexion, especially during the heel off and propulsion. Varus and valgus wedges are added to carry the correction forward from the distal edge of the orthotic. So on a regular orthotic when you go into heel off into propulsion, you lose the effect of the orthotic. And so if the rearfoot control doesn't result in the medial column plantarflexion during propulsion, you want to add one of these wedges and basically a varus wedge is paper-thin under the fifth met and thickest under the first met. So we are creating an inverted platform for that foot to resist pronation once that heel comes off the ground. Valgus wedge, of course the exact opposite, it's paper-thin under the first and thick under the fifth creating an everted wedge across the forefoot to promote pronation to resist any unwanted supination from heel off into propulsion. Again, you are filling up the toe box of the shoe. So varus and valgus wedges, I would highly encourage you to only put them in shoes with removable insole. Toe crests are added when you want to fill the sulcus groove. Excellent modification to stabilize rigid or ascending rigid hammertoes. It can be ordered from soft or firm material.


    Soft if you are looking for cushion and grip, more firm material if you are really trying to support those toes in the sulcus area, typically combined with a lot of other combinations or modification so that we control that foot all the way through the entire gait cycle. So the goal of our orthosis is to contour as much as of that foot as possible, fit the patient's foot comfortably and still fit in the shoe. So if you don't give the lab instructions, they are going to want to make a less contoured orthotic and they are going to want to make a narrow orthosis. Less contour, so it's more acceptable to the patient, narrower so it will fit in shoes better. The doctor typically wants more contour and a wider orthotic because you want to control that patient and so it's so important to specify not only the size of the shoe but the type of the shoe. So if you have ordered something in your prescription that's not going to fit within that shoe, we can notify you rather than you get it and it doesn't fit. In addition, if they are wearing super fancy dress shoes, if we can get a representative sample sent to the lab, it makes a heck a lot easier to make sure that orthotic fits out of the gate. But there are times when you want wider or narrower orthotics. Cavus feet with metatarsalgia, you want that orthotic as wide as possible or if you are trying to get the first to drop and function below the second through the fifth, you are going to want to narrow that orthosis medially, possibly even grinding back to medial distal tip to make plenty of room for that first to drop and function below 2 through 5. And you always want to advise your patients to buy shoes with removal insoles. Most of them come that way now but it makes your job a heck of lot easier when you are trying to fit a full orthotic and always have them take their orthotics with them when they purchase new shoes.


    There is a couple of studies I have got in here. I'm not going to go through them but they are all about the efficacy of foot orthotics and if you need something for your medical files or you just want to read the reports, just talk to Present and they will give you that slide and you can find those studies and see what it's all about. So why would you use an ankle foot orthotic instead of a foot orthotic. Well, foot orthotics promote normal function of the foot but they really can't sufficiently restrict abnormal motion because of either abnormal muscle function or abnormal nerve function whereas an AFO can do this because the orthotic is actually attached in wraps-up on the posterior aspect of the ankle. There are two basic types. There is your solid AFO. So this AFO has a plastic shell all the way down the posterior under the heel and all the way to the ball of the foot. So it really restricts all three planes of motion, all three. So it makes it a little difficult for a patient to ambulate in a solid AFO and so they develop these articulating ankle AFOs and you put a rivet right at the malleolus line that allows the orthotic to plantarflex and dorsiflex against the uprights. And this makes it much easier for the patient to move around as well as it gives you better shoe fit. AFOs can have one or more treatment goals. You can limit motion of a joint. You can restore motion of a joint, for example, drop foot conditions, decreased load on soft tissue structures or offload ground reaction sheer forces or just purely to improve balance and proprioception.


    Again, here is seven studies on AFOs, all the same thing and if you want that, just let Present know and they will get to you or contact me and I will get it to you. So AFOs are made from the exact same materials that we make all the foot orthotics. What does that mean? That means you can make all the same modifications to an AFO. You can modify the positive or the orthotic shell to increase or decrease the efficacy of your device. So you can add rearfoot post. You can offload tender areas. You can raise your lower heel cups. You can add varus and valgus sulcus wedges. Anything that you can do to a regular orthotic, you can modify in your AFOs. There is three modifications that you really can't do in a regular foot orthotic. So Tamarack hinges, which is right there, is designed to create a dorsiflexion moment as soon as the heel comes off the ground. It's ideal modification for your dropfoot patients. Couple of things though that you need to know if you are going to order Tamarack hinges. First of all, you have got to have a stable knee. Second of all, you have got to have passive dorsiflexion at the ankle to at least 90 degrees and lastly, you can't have any posterior spasms in that lower extremity. Restricted hinge are taking articulated hinged brace and trying to make it more like a solid AFO. To do that, we add a second rivet right where the first one is at and it really stiffens up this aspect of the brace. Now it's not as restrictive as a solid AFO. So your solid AFO, you are indicated with global DGD of the ankle, subtalar joint and mid foot and where you have got severe deformity of the foot whereas the restricted hinge functions beautifully with far better shoe fit and ease of wearing for the patient.


    And so we see much more of this type of a product on than your solid AFO for your more advanced deformities. And then we have lateral and medial arch suspender. So these we add to allow the patient to make adjustments for how much support they are getting from the brace. And what we do at a lateral arch suspender is we grind out the area in the mid foot laterally and we attach the strap that goes around and up and connects on the medial side. So the patient can actually adjust how much force is being applied along the lateral column. These modifications are usually great for lateral instability where you want to give the patient some control. Same with the medial arch suspender. What we do is we grind out that area and attach a strap to it where that goes up laterally so the patient can apply pressure and adjust the amount of medial pressure in the brace itself. So your indications; ulceration or a lesion at the TN joint, severe deformity or bulging of the TN joint or symptoms of medial ankle pain fail to improve with the initial brace prescription. Your contraindications; severe forefoot abduction, and if you have a very obese patient because the shell cut out is going to weaken the device. Couple of little pearls. Add a lateral phalange and restricted hinge with all medial arch suspenders because you are making the brace and the orthotic a little more flexible. This will stiffen it up just enough to make it good and functional and still allow the patient to self-adjust the medial arch suspender. On the lateral side, this is excellent modification for your varus deformity, peroneal tendinopathy and lateral ankle instability. So in summary, your primary goal is to improve foot and ankle function and/or alleviate pain. Surgery, orthosis and pedorthics, these are all the tools you need to achieve that goal. And clinical biomechanics is the core knowledge required to use these tools and of course the best practitioners are going to use all three. And so this is how you become the regional specialist of the foot and ankle. This is how you become the go-to person for pathologies of the lower extremity. Thank you.

    TAPE ENDS [30:50]