Webinar: Introduction to Locking Technology

right hi there everyone I can see the numbers going up welcome to everyone who's joining we'll just hang on for a few minutes I think there's probably a bit of a cue in the waiting room so we'll just uh we'll just hang on for a couple of minutes until our numbers have gone up a little more hi ritika just saw your message on the chat nice to see you keeping an eye on numbers I can still see the numbers going up foreign numbers seem to have slowed down a little bit now so um I will make a start hi Muhammad thanks for your message saying hello okay um I'm gonna make a start so um thanks ever so much uh to everyone for attending um this afternoon or this evening I think it is with most of you um so today's webinar um by Nikki Meadows is an introduction to locking technology so just to introduce myself because I think many of you who are on the call um won't have met me my name is Rachel Beacham I'm the clinical training coordinator for veterinary instrumentation I am a registered Veterinary nurse um I hold the Royal College of Veterinary surgeons advanced nursing diploma I have been out of practice for 10 years that 10 years I've been with Veterinary instrumentation I came from an orthopedic referral nursing background um and the time that I've been with Veterinary instrumentation up until the beginning of this year I was part of the veterinary technical support team um I've been in the clinical um clinical training well now for just under a year that's enough about me um I'm not the star of the show today and so just to introduce our speaker for today's webinar at Nikki Meadows so Nikki graduated from the Royal Veterinary College in the UK in 2006. she spent six years in General's small animal practice and she then completed her rcvs small animal surgery certificate became an RCBS recognized Advanced practitioner that was in 2013. Nikki now works as a mobile orthopedic surgeon she provides an in-house referral service to First opinion practices in greater London and the southeast of the UK so today's webinar as you know is an introduction to locking technology so this is an area of interest to Nikki obviously a lot of what she does in her referral work is is fracture repair and locking technology is an emerging technology for fracture repair so this is a a very interesting topic we are as ever very very grateful to you Nikki for your time and expertise and for working with us to deliver this webinar to you all this evening so um just a little bit of uh General sort of housekeeping uh before we start the webinar um a couple of you have said hello on the chat function which is lovely thank you hello to everybody um we will ask you not to use the chat function during the webinar but the Q a function is open and my colleague Stella is monitoring um the Q a so if you have questions as we go along um please type those questions in the Q a uh section and if that question hasn't been answered as we go through the presentation there will be lots of time um for questions at the end so anything that's not answered as we go through will be dealt with at the end and then you compose further questions at the end as well this webinar is being recorded and you will all receive um a link so that you can view the webinar again via that recording link and we will also be supplying you with CPD certificates those will come to you um via our colleagues at Euro vets so I think that's um I think that's everything in terms of a preamble so Nikki I'll hand over to you thanks very much thanks Rachel good evening to everybody um so as Rachel said already this webinar is going to cover the introduction to looking technology um so on the agenda this evening we've got a quick overview of the principles of fracture fixation which will probably be revisioned for most of you who are already doing Orthopedics we'll take a look at the differences between Dynamic compression plates and locking plate technology and then we'll have a little look in a bit more detail about the variations the types of locking systems that are available um we'll go through some considerations when using a locking system and then look at some case studies which will helpfully uh hope hopefully uh help to cement everything that we talk about during the webinar so we'll just have a quick overview of um fracture and Fracture classification there are a number of different ways in which fractures are classified and different ways to describe them um they can be described by anatomical location whether they're open or closed fractures um the extent to the damage to the Bone to a simple transverse fracture versus the community fracture um uh looking at the configuration of fracture lines how displaced fragments are and how stable the fracture is as well and it's important that we can accurately classify fractures and describe them so that we can discuss them accurately between colleagues um everybody is probably familiar with looking at fracture assessment scores but this is one of the first things to do when you're presented with a fracture um to look at different factors that may influence how well this fracture is going to heal and what kind of fixation is going to be suitable for the fracture so the first one to consider is mechanical factors we look at how stable the fracture is inherently based on its configuration what type of forces may be acting on that fracture the body weight concurrent injuries of a patient and the activity levels of a patient so a young exuberant puppy versus an older more sedate patient um clinical factors are the next ones to consider including owner compliance the nature of the patient the environment that the patient lives in so for example whether they're a dog that lives outside permanently whether they live in um a house all on one level or whether they live in a flat and have to go up and down several flights of steps to go in and out of the flat on a daily basis biological factors are the next thing to consider and we're really looking here at um the healing potential of the fracture based on the level of tissue damage that may be present as the factory occurred and the patient age and concurrent illnesses for example diabetes which might impair healing each factor is given a score for one to ten low scores are patients that will require robust fixation and the implants are expected to work quite hard in these types of fractures um load sharing may not be possible fracture healing may take longer than usual moderate scores fractures that require less implant strength and less implant endurance and high scores are fractures where the implant stress is likely to be due to low low due to low sharing at the fracture site or if you've got a very young patient that may have quick healing so just an overview of um fracture healing and again this is probably revision for most of you there are two types of um fracture healing primary or direct healing um and within that we have contact with gap healing um and then secondary or indirect healing and this is the most common type of fracture healing that we see most fractures heal with a combination of the two mechanisms it's quite rare to see one exclusively over the other um direct healing usually occurs under conditions of absolute fracture stability and this is only achievable with surgical intervention so in gap healing we're looking at fractures with a fracture gap of less than one millimeter in contact healing we're looking at fractures that have got direct interfragmentary contact and there's no motion at the fracture site at all so direct healing occurs by osteoanal Remodeling and it occurs without callus formation and is particularly desirable um in anatomical locations that are next to a joint for example where you don't want to have lots of callus forming uh in this type of healing catacombs create the tunnels in a compact bone and they form new perversion osteotones across the fracture line um and in that way you get Gap peeling or contact healing in indirect healing um you do get callus formation so initially hematoma formation occurs um and then soft callus forms at the site of the hematoma as new blood vessels invade the hematoma um you get both internal and external Callister the fracture site and then the next thing that happens between six to 12 weeks post fracture is that hard callus forms so that soft callus that was previously present starts to become mineralized and then there's a remodeling phase which can take months or years post fracture to happen as the bone remodels and the callus remodels and you end up then with a normal looking bone after the callus is completely remodeled so just take a moment to have a revision of the principles of fracture repair and these are our AO principles of fracture repair again probably familiar to most of you and there are four main principles the restoration of normal anatomical relationships uh fracture fixation to provide relative or absolute stability to the fracture site preservation of the blood supply and soft tissue which is really quite important for fracture healing early and safe mobilization of the injured limb and the patient is a home there are two main approaches to fracture stabilization but in reality actually um it's a kind of sliding scale between the two approaches at one end of the scale we've got open reduction and internal fixation or orif and this is an instance where you would expect precise anatomical reduction of all of the fracture fragments that allows low chairing of the weight-bearing forces between the implants and the bone this type of factory fixation reduces implant stress and protects the implants from fatigue failure because the bone is sharing the weight bearing at the other end of the scale we've got minimally invasive or a biological approach for example this can sometimes be referred to as the open but do not touch approach this is used for more complex fractures where you're going to be unable to anatomically reconstruct the fracture fragments or if you were to try and do that it would be a massive cost to the soft tissues and blood supply so this type of fracture stabilization um is typically where implants are used in bridging or buttress function and that means that the soft tissue attachments in the blood supply to the fragments are preserved and each type of fracture approach is more appropriate in certain fracture configurations so in this example of a reconstructible fracture you can see that we've got a slightly oblique distal radial and ulnar fracture here this fracture is definitely reconstructable without too much cost to the soft tissues surrounding the fracture fragments this fracture can be load sharing as well which will protect the implants from fatigue failure this type of fracture that you can see which is a markedly common muted fracture of the mid die femoral diopasis is non-reconstructable and you can imagine that the cost to the soft tissues and blood supply if you were to try and reconstruct this type of fracture would be huge um and that this type of fracture uh is not immutable to load sharing at all so in this type of fracture the implants are going to have to be doing all of the weight bearing whilst the fracture heals and this type of fracture is likely to take quite a long time to heal compared to the previous example because there is such disruption to the soft tissue and blood supply at this fracture site and in this type of fracture you'd want to take a more biological approach so you might do an open but do not touch approach where you don't disturb the fracture site further at all and you just Place implants in the proximal and distal bone stop that you've got I just want to have um touch on the different function of bone plates broadly speaking there are three different types of functions for bone plates compression neutralization and buttress or bridging plates and compression plates um the fracture bone-ins are compressed as the name suggests and this results in a high level of bone load sharing which will protect the implants from fatigue failure and this type of bone plate function is really only applicable to certain types of fractures neutralization plates don't compress the fracture fragments um but typically the fragments are accurately reduced and stabilized and this results in some load chairing between the bone and the plate um occasionally in neutralization plates additional implants are used so positional screws or lag screws are used um in order to reduce the fracture fragments and then the neutralization plate is placed to protect the positional or lag screws that have been placed plates that are used in buttress or bridging function maintain the reduction in limb alignment but actually there's no load sharing at all and as in the last example of a non-reconstructable fracture that very comminuted mid-dipocial femoral fracture there's no load sharing at all any implants the plate and the screws are being asked to take all of the load whilst this fracture heals we'll just take a closer look here at a compression plate um so we've said already that a compression plate compresses the fracture bones together and this is relative to the long axis of the bone and this results in a higher level of load sharing between the bone and the implants um and in these diagrams here you can see that we've got a dynamic compression plate and these holes have got sloping shoulders which means as you tighten the screw uh the screw slides down the shoulder and the bone is compressed against the other fracture end and this is the resulting compression at the bottom of the picture here in a neutralization plate the fracture fragments are not compressed by the plate in this example you can see that there's a lag screw being placed across the fracture line perpendicular to this fraction line here the red line and that reduces fragments accurately it does result in some load sharing and then a neutralization plate is used adjacent to the fracture and that supports the lag screw and protects the lag screw whilst the fracture heals the last type of bone plate function is about Trestle bridging plate in this example the plate maintains a reduction in limb alignment but there isn't any load sharing tool the plate in the screws are being asked to take all of the load here as you can see in this example of a combinated fracture centrally just here um so I want to touch on a dynamic compression plate in a little bit more detail now um when you use a dynamic compression plate the construct of the screws in a DCP Dynamic compression plate stability relies on friction between the plates and the bone and this is created when the screw thread engages in the cortices of the bone and it pulls the plate down to the bone and the bone up to the plate so you end up with friction between the bone and the plate if you've got a plate that isn't quite perfectly contoured to the Bone then as you tighten the screw and the bone moves towards the plate it's going to result in loss of reduction of your fracture fragments as in this diagram here so you can see that this plate hasn't been properly contoured and as this screw has been tightened we've lost reduction at the fracture site just here um so Dynamic compression plates are really useful to create compression a fracture site but it is important that they are properly contoured to the Bone so that you don't lose reduction of your fracture fragments you can create in into fragmentary unidirectional axial compression and this is achieved by placing screws essentially or low in a loaded fashion and as I said before the screw had slides down the sloping or incline shoulder of the screw hole and this means that the fracture fragments are compressed together in this picture here this screw is being placed in a loaded fashion and you can see that the drill hole is eccentric within the plate hole here display this screw sorry is placed in a neutral fashion and you can see that the drill hole is placed in the center of the hole in the plate Dynamic compression plates screw holes are useful because they allow the cortical screws to be angled um plus or minus 25 degrees longitudinally and plus or minus seven degrees transversely and this can be particularly useful function if you're trying to avoid important structures like joints or 5Cs and juvenile patients as well there's a specific load neutral drill guide that you need to be using with Dynamic compression plates um the gold end here has got an offset hole and you can see in this diagram that the hole is offset and that results in your pla in your scrubing placed in a loaded fashion the green end of this guide is a neutral guide and the hole you can see here is placed centrally within the plate screw hole now in the gold and the offset hole there's an arrow which is clearly etched into the guide and it's important you always have the arrow pointing towards the fracture line to create compression in the right direction so this is a short video here just showing how a load neutral drill guide works the load neutral drill guide is used with the dynamic compression plate the device is size specific because the tips of the device must fit snugly into the oval holes of the plate the vi device is etched with the correct size pilot drill one end of the load neutral drill guide has an offset hole the tip of the device is positioned to create the pilot hole at the far end of the oval plate hole away from the fracture the arrow is positioned so it points towards the fracture this ensures correct offset positioning at the pilot hole the other end is for neutral positioning of the screw in the center of the plate hole there is a second type of drill guide that can be used and this is used really with Dynamic compression plates um or dynamic locking plates they can be used in either um it's essential this is the drill guide that you would use in a dynamic locking plate um but you could also use it in a DCP as well there's a spring-loaded tip in the drill guide and that allows you to drill in either a neutral or a loaded position um the single size drill guide according to plates and screw size will be clearly etched on the universal drill guide um and it's got a standard drill guide at the other end which means that you can use this as a guide for tapping or for a clearance drill if you want to place a live screw um so you can see from these diagrams here that this is the neutral position of the screw at the spring-loaded tip of the drill guide and you push down on that in order to get the neutral position when you're not pushing down in the loaded position um which is if you want to place the compression screw you just place the universal drill guide in the plate hole away from the fracture line and you don't press down on the spring loaded tip this is a short video which shows how the universal drill guide works the universal drill guide can be used with either a dynamic compression plate or a dynamic locking plate the universal drill guide has a sprung tip to achieve positioning of the pilot hole in the loaded position the spring-loaded tip is simply placed into the end of the plate hole no pressure is applied to the sprung tip this will position the pilot hole correctly for a loaded screw to achieve neutral positioning of the pilot hole the device is placed into the plate hole and pressure is applied to the spring-loaded tip this achieves Central positioning for the pilot hole the other end of the device has a simple drill guide of a size appropriate for either a clearance drill or a tap device remember a universal drill guide can be used in either a DCP or a DLP so I want to move on now to have a look at locking plates in a little bit more detail and the first thing to have a look at is the mode of action of the Locking plate we've already discussed that in a dynamic compression plate the plates and the bone are pulled together when the screw threads Engage The Bone cortices and that creates friction between the plates and the bone and it's that friction which makes the construct stable and a locking plate the screw head itself engages the plate and the screw thread in the shaft of the screw engages the bone cortex which means that the bone fragment isn't pulled up to the plate there's no friction required between that plate and the bone in order for this construct to be stable and this means that there's a reduced requirement for accurate plate contouring you remember with the DCP the plate needed to be very accurately contoured so that fragments didn't lose reduction and that's not the case in a locking plate you don't need to accurately Contour your plate but it's not quite as important with a locking plate so in this slide um I've just got a comparison here for you to remind you of DCPS versus locking plates so a DCP relies on compression between the plate and the bone to create friction screw insertion pulls the fracture fragments to the plate and can alter the fracture reduction if the plate contouring is not accurate with the DCP it's really important that you have bi-cortical screw purchase to prevent the screw pull out by toggling um that's not the case in a locking plate as we'll come on to in a moment with the DCP the load is concentrated screw to screw and again that isn't the case in a locking plate so with a locking plate the mechanism um doesn't rely on friction between the bone and the plate um screw insertion doesn't change the reduction of your fracture fragments because the bone isn't pulled up to the plate very usefully you can use unicortical screws in a locking plate they don't have to be biportical as they do with the DCP and that's because um it's really difficult to have the screw pull out with a locking plate and it certainly doesn't happen via toggling mechanism load is transferred and shared equally amongst the screws in the Locking plate as you can see in this diagram here foreign we're just going to have a look at the difference here between a cortical screw and a locking screw so um a cortical screen we've got a standard sloping screw head here with no thread um the core size of a cortical screw is smaller than a locking screw and this means that there's less resistance of a cortical screw to bending than there is for a locking screw and the thread pitch on a cortical screw is slightly looser as well which means that you have reduced bone screw interface when compared to a locking screw a locking screw has got a threaded head as you can see in this dark image here um there are thin fine twin start threads to the screw head there's a much larger diameter core size which means it's an increased resistance to bending the thread pitch is tighter which maximizes the bone screw into place most of the Locking screw heads have got a torque at the Star Drive which allows a higher torque for screw placement and is also self-retaining when you put the screw into the screwdriver a locking screw by is required to ensure that the pilot hole is created perpendicular um to the plate and that allows the thread of the screw head to lock into the plate hole in the correct position so when you're using locking screws it's really important to ensure that you've got the correct locking screw drill guide foreign with a dynamic compression plate as we've already talked about you can have failure by pull out of the screws and this happens when the construct the bone plate construct is subject to bending loads and the screws actually toggle one by one within the holes and loosen and are pulled out sequentially as you can see in this diagram with a locking construct there's a much higher resistance against the bending load and instead of the screws being sequentially toggled and loosened and pulled out of their screw holes if you were to get failure of your locking construct actually what happens is you get pulled out of the screws with a large fragment of bone this is really unlikely to happen but that would be the mechanism of failure rather than sequential pull out of the screws so there are several advantages to locking plate technology the construct is much more rigid than with a dynamic compression plate and this is because the screws lock into the plate and have got angular stability and it can be described as an internal external skeletal fixator so like an external skeletal fixator but under the skin um screw loosening doesn't occur as it does with a dynamic compression plate um because the screw is um locked into the plate the screw bone interface does not determine the strength of the contract construct as it does with the DCP which means that locking technology can be particularly useful for soft bone if you've got a juvenile patient or for diseased bone if you've got an older patient or if you've got very small fracture fragments you're not relying on that soft diseased or very small fracture fragment bone to determine the strength of the construct precise contouring of the plate is not always necessary and that might reduce your overall surgery time which is definitely got its advantages um the strength of the construct doesn't reply rely on a plate bone friction as a DCP does and that means that you've got a reduced peristal periosteal and soft tissue disruption and therefore you maintain a better blood supply to your fracture site which means that healing will be faster uh locking plates tend to provide a more stable fixation than conventional constructs um there was a paper in the last few years that her found that there were decreased infection rates in giant weed tplos um supposedly because the construct was more stable and if anyone is interested in that paper please do let Rachel know at the end of I can email it over to you um Dynamic locking plates can be used in both compression and locking mode so you can have the best of both worlds with the dynamic locking plate you can compress your fracture side but also provide a rigid construct with your locking mode as well there are a couple of different types of Locking System available there's a monoaxial Locking System where the screws are inserted and locked perpendicular to the plate and so this is called an angle stable system there's also polyaxial systems as well where the screws can be angled in relation to the plate and this allows direction of the screws away from articular surfaces and Fracture lines and also Pisces in our juvenile patients as well um there are a number of different types of locking plates so we've got a dynamic locking plate as I've already discussed and with the dynamic locking plate you've got both a dynamic compression unit so you can compress your fracture site but also at the other end of that hole you've got a locking unit as well now what that means is that you can apply axial compression with your cortical screws to compress your fracture line and then you can apply monoaxial locking screws to make a really rigid construct after you have compressed your fracture site and the cortical screws as with the normal DCP can be angled in this system which can be useful for avoiding important structures as we discussed before the second type of Locking System that you might encounter is one that just simply allows you to look the Constructor your screws so sometimes these allow for polyaxial application of locking screws but not always we don't see polyaxial locking screws available with a dynamic compression unit so Dynamic compression units are always monoaxial locking screws and with a locking plate some of them are monoaxial and some of them are polyaxial so there's a number of different ways to achieve locking of your screw to your plate we've discussed the monoaxial threaded head already where you have a tight thread on the screw head and that locks into a corresponding thread in the screw hole as you can see in this Photograph here on the plate conical coupling is also available this is another monoaxial system so you can't angle your screw with this system screws are inserted into a bushing within the plate so you have your screw which isn't a non-threaded head and that inserts into this bush in here which is screwed into the plate and this is what the whole unit looks like here and then finally there's a self-cutting screw head which is available and this is a polyaxial system you have a titanium screw which has got a thread on it and that cuts thread into the plate on insertion so as you insert the screw into the screw hole a thread is cut for that screw and this kind of system allows you to angle your screws away from important structures but it does not allow you to compress across your fracture line at all there are lots of different sizes of locking systems available um from 1.5 the smallest all the way up to

3.5 broad um just as if you were using a DCP screw diameter shouldn't exceed 25 of the width of the bone that you're going to apply the plate to um Veterinary instrumentation I've got a useful advice service um and they'll be able to offer advice on what size implant will be suitable for the type of fracture that you've got um but there's a very useful plate selection resource and that's available in the catalog and online that's a very good starting point for looking at any type of implants that you might want to use for certain fractures so locking technology is broadly applicable to any fracture but you may find it particularly useful in the following circumstances we've already talked a little bit about juvenile bone which is softer and where food purchase and Bone plate friction isn't optimal so locking technology would be more useful in this scenario than a DCP that relies on the bone plate friction to stability elderly patients where the quality of bone might not be what it is in a younger patient and therefore bone plate friction would be sub-optimal if you were to apply a DCP if you've got the fracture like the mid Darter seal comminuted fermal fracture we saw earlier where that fracture is likely to take quite a long time to heal you've got a prolonged healing time and you want your implants to last and be stable for a really long time a locking system is probably more appropriate than a DCP fractures that are juxta articular with small fragments where you might need to use a monocortical screw rather than a bicortical screw to avoid an articular surface mean that Locking System is more useful than a DCP where you need to have bicortical screws locking systems are also really useful if you want to perform a minimally invasive approach to fracture repair so I'm either an open but do not touch approach um or minimally invasive um osteosynthesis approach where you just make stab incisions in the skin and Slide the plate up alongside the periosteum without opening the whole fracture site up Dynamic locking plates are the most versatile type of Locking System more so than just locking plates that don't have a compression function that's because you can use a DLP in a compression mode and a locking mode together um or you can use them with a locking mode alone in buttress and bridging function you don't have to apply a compression with these plates so with a DLP one of the useful functions is that you can pre-contour your plate um to your bone and then apply your cortical screws first and that means that your bone is going to be pulled to your plate your plate is already contoured so in that way you can Aid uh fracture reduction by pulling your bone to your pre-controlled plate um you can create compression axial compression across a fracture line using your cortical screws in compression function and then once you've created your compression and you've got your reduction in place you can apply your locking screws in monocortical fashion if you need to or by a cortical fashion and the Locking screws then make the construct more stable one of the absolute golden rules in using a dynamic locking plate is that you always always place your cortical screws first to reconstruct your fracture and to get compression across your fracture line and then you place your locking screws last to increase the stability so you must always place your cortical screws before your locking screws now there are enough of a number of other applications of locking technology um lock Rod is something that's particularly useful in feline long-bone fractures um particularly comminuted fractures so with a lock Rod there's a chamfered ski tip which enables you to perform minimally invasive insertion of the plates so as I said before through stabbing incisions in the skin you can slide this implant then up alongside the periosteum subcutaneously um and then just uh apply your screws to this implant through very minimal approaches proximally and distally this is a monoaxial system which means that your screws are applied perpendicular to your implant and it's available for use with 2.4 and 2.7 millimeter locking screws only in this system um so in this Factory example that you can see on the slide you can see that the mid die facil fracture is comminuted these fracture fragments are not going to be reconstructable the fracture isn't going to be load sharing um which means that it's suitable for a minimally invasive or open but do not touch approach you're not going to do anything with these fracture fragments anyway the medial surface of the tibia of the cat has got very little soft tissue to it and so it lends itself very nicely to a minimal approach where you can just slide this implant up underneath the skin through a stab incision distally and then secure it proximally and distally through just stab incisions there are a number of other applications of locking technology tplo plates are particularly useful because you have a relatively small fragment in the proximal tibia after performing a tplo so it's useful to have locking screws proximally in that particular small fragment locking T plates um and we're thinking here particularly of distal radial fractures um where you don't have very much Phone Stock distally and you've got a small fracture fragment and you can see in the plate that's Illustrated here we've got quite a large bridging for um bridging portion of the plate here and you could apply these two screws to your distal radius um two locking screws so you'd have a nice stable construct there plates also come with a locking function which is useful um particularly when looking at smaller Bones the metacarpals in particular um and then there are cottonable malleable locking plates and these are very useful to use in a buttress function but not if you've got a long bone fracture um that's going to be weight bearing so I wouldn't use this type of locking plates alone in say for example a tibial or femoral or radial fracture but they can be very useful in things like Jaw fractures or Y fractures where you've got other fixation as well and then the last application that's available is in locking TPO or DPO plates so we just revise the steps in applying locking plate we've already covered this really but I'm just going to go over it again before we have a look at some case studies um so you want a template from a normal radiograph similar radiograph sorry with your normal limb if appropriate so template your plate contouring and then you want to Contour your plates and if you're going to use it to Aid your reduction or to compress a fracture then you are going to be applying cortical screws and you want to Contour this plate perfectly if it's acting in batteries or bridging function only and you're not planning on applying cortical screws um then approximate contouring is absolutely fine so the next step would be to apply your cortical screws first in neutral or compression using the universal drill guide and then lastly you want to apply your locking screws using the size specific locking screw drill guard um it's so important to remember always apply your cortical screws first locking screws second so we're going to move on now just to have a look at a few cases which hopefully will help to make you think a little bit about what we've been talking about today already so case number one is Daisy who's a 10 month old 12.7 kilogram female entire

Cockapoo and she was out playing with a ball uh jumped for the ball and then presented at the clinic with a cute onset left pelvic limb lameness and on examination we could palpate crepitus and pain um uh pain response on palpation of her left cross so we went on to radiograph her and the radiograph revealed a minimally displaced closed oblique fracture of the left tibia at the level of the distal one-third of the diaphysis um and going on to have a look at the fracture considerations for this particular type of patient I've given this fracture a score a mechanical score of six um because we can get some load sharing from this fracture um a clinical score of four and a biological score of eight this fraction is fairly minimally displaced um and this is a young patient so she's going to be healing quite quickly um we've got reasonable bone stock approximately here and less bone stock but still reasonable bone stock distally here there's um open vices at the distal and proximal tibia which are going to be important to avoid because this patient is immature that's always a consideration um so we went on to repair this fracture um by open reduction and internal rigid fixation um a positional screw was placed across the fracture line here to reduce the fragments and then a 2.7 millimeter Dynamic looking plate was contoured approximately and used in buttress function applied medially to the tibia these radiographs have taken six weeks post-operatively and they reveal excellent bony Union here and this patient went on to make an uneventful return to function so this is quite a nice illustration of how a dynamic locking plate can be used um as a neutralization plate over the top of a positional screw which has reduced the fracture fragments nicely the next case that we're going to go on to look at is a little bit more complex this is Toby who's a five-month-old 1.7 kilogram male entire toy poodle um he jumped off the sofa and was non-weight-bearing on presentation um there was crepitus on palpation of his left elbow and he had quite a marked pain response to palpation of his left elbow we went on to radiograph him and found that he had a displaced closed y fracture to the left distal humerus considerations for this particular fracture are a little bit trickier than the first case so I've given this a low mechanical score um the fracture is reconstructible for load sharing but we're in essence dealing with three fracture lines here I've given this a clinical score of Two and a biological score of six because this patient is quite young so he's likely to heal relatively quickly other considerations are that this is an articular fracture so we need absolutely accurate reduction and rigid stabilization so that we don't get callus formation next to the Joint um the bone is going to be soft because this is a juvenile patient and we've got relatively small fracture fragments so a limited bone stock and this is a really small patient so we needed to use quite small implants in this chat obviously we went for open reduction and internal fixation in this case um because this is an articular fracture and we need these fragments to be absolutely perfectly reduced we reconstructed and stabilized the condyle with a 2.4 millimeter locking

screw and then repaired the medial condyle with a 1.5 millimeter Dynamic locking plate in buttress fashion so we didn't apply any compression or any portable screws to this at all and the lateral condyle we used a cuttable malleable plate of 1.5 locking possible malleable plate and this was applied in buttress fashion again um and this was quite a useful plate to use here in combination with the DLP on the medial condyle um I wouldn't as I've said before use the malleable plates um in a load-bearing capacity uh by itself but it is a useful adjunct to use um in fractures such as this or dual fractures perhaps so we're going to have a look now again another juvenile patient this is Lottie who's a nine week old 5.9 kilogram female entire Labrador Retriever um jumped out of her owner's arms and became acutely lame on her right pelvic limb there was swelling on palpation of her right cross now we took some radiographs that showed a minimally displaced closed oblique spiral right tibial fracture that extended from the tibial metaphysis so you can just see the fracture line on this medial lateral projection here extending down here um so the spiral is quite long in this fracture um and it extends all the way down to the distal one-third of the diaphysis as you can see on this for any cordial View in terms of fracture considerations the fracture assessment score for this patient was actually quite High mechanically um we thought that we could get some load sharing with this fracture but that it wasn't vital because this patient is so young that healing is going to be rapid we're not going to need these implants to last for a really long time so it's not vital that load sharing occurs in this fracture um she's got a really high biological score because she's likely to heal very quickly the bone is going to be really soft because this is a juvenile patient which means that locking construct is going to be most useful here she's got reasonable bone stock available proximately and distally to these fracture lines but we do need to be careful to avoid these 5cs now you'll have noticed that this is just a tibial fracture and the fibula is actually still intact and this can be very useful in these juvenile spiral tibial fractures because the fibula being intact actually protects the plate really well against bending forces so you don't need to apply an intramed every pin or an orthogonal plate in these types of fractures there's no need for adjunctive stability here I've included this case study to show how we can use locking technology in a minimally invasive fashion so this fracture was repaired by minimally invasive plate osteosynthesis a mepo technique which means that the fracture site was not Disturbed at all which results in a soft tissue and Vascular disturbance being absolutely minimal there was no need to disturb the fracture site in this patient we just needed to provide stability proximally and distillate to the fracture in order for it to heal because there was going to be no reconstruction and we decided that before we started this fracture was repaired this is an interoperative photo here showing that we've got a stab incision approximately establishes incision distally and we've just slid this plate up underneath the skin adjacent the periosteum and we've got needles here in the proximal and distal tibial vices to Mark out where they are so that we don't inadvertently place at the screw within the vices um the surgical time this patient was about 15 minutes so very short which is desirable when you've got such a young patient you don't want them to be asleep for ages um getting hypoglycemic under anesthetic so this last case study that we're going to go through um is a six-month-old seven kilogram female entire Shetland Sheepdog miniature Shetland Sheepdog she jumped out of her owner's arms and became acutely lame on her left thoracic limb there was swelling on palpation over her left radius and pain on palpation as well when we radio rafter we saw that there was a minimally displaced closed transverse fracture to the left radius and the distal one-third of the diaphysis so this is quite a typical fracture to see in our small breed dogs that jump from height um and we have actually got quite a lot of bone stock distally here but very often we'll see very minimal bone stock in these types of patients distally which is where the Locking tape that we looked at earlier comes in very handy so this patient has got a relatively High fracture assessment score again she's a juvenile patient she's going to heal quite quickly the fracture is reconstructable for load sharing it's a transverse fracture so we should be able to compress that and get some um load sharing going there to protect our implants but we wouldn't necessarily expect the implants to have to last for a long time because the fracture healing should be quite quick as I've said we've got moderate bone stock available distally plenty of bone stock proximally but again this patient is juvenile so we need to avoid these Pisces foreign no this is a case that was referred over to me for management after its initial surgery um so this surgery wasn't one that was performed by me initially um but the fact she was repaired by open reduction and internal rigid fixation um the plate has been placed to avoid the feces which is a positive and locking technology is being used and that's desirable in this juvenile patient with soft bone and a relatively smaller distal fracture fragment although there is still quite a lot of bone stock destiny so a 2.7 polyaxial Locking System was used in this patient and the plate was placed dorsally on the radius um well I'd like you to take a look at in these post-operative images um is the ulna here the distal ulna and also the bone density underneath this plate here so when I move on to the next slide keep in mind what you're seeing here so radiographs of this patient were obtained three weeks postoperatively so these pictures that you can see are three weeks post-operatively and initially everything looks to be okay um so on the CC view here this all looks to be okay the implants are in place there's no evidence of implant loosening but on the media lateral projection we can see thinning of this ulna here so we've got atrophy of the ulna and we've got osteopenia of the radius underneath this implant so we've got a 2.7 implant here in this small patient and we've got osteopenia starting to appear under the plate now in these images it's relatively subtle um but it's definitely there um um it wasn't until seven weeks post-operatively that this patient was referred to me for ongoing management and you can see what's happened here is we've got further osteopenia of the radius underneath the plate and further atrophy of this ulna almost to the point of it disappearing here underneath the plate um so early on a three weeks postoperatively we see signs of what's called stress protection um but as seven weeks postoperatively when the construct has remained unchanged and we've got a very stable construct here for a small patient uh we've got further Evidence here of stress protection so at seven weeks um I opted to dynamize this construct and what that means is I removed two screws screw number two here and screw number three here in order to make the construct less stable to try and stimulate further bone growth um so I removed these two screws for a staff incision rather than going in and revising the whole fracture at this stage um so it's a relatively conservative approach um rather than removing the entire construct but 12 weeks post-operatively after several more sets of radiographs it was evident that just dynamizing the structure hadn't done the trick and the owner by this stage had actually um run out of money to revise this fracture repair so what we opted to do at that stage was to remove the implants completely and you can see that we've got really marked atrophy of the ulna down here really marked that tree of the radius on the CC projection as well and you can see that we've got quite marked osteopenia in the position where the plate was um so in this type of case we've got a real risk of fracture either through an old screw hole or through the osteopenic bone um because this owner didn't have the financial support for a further revision surgery we actually placed a splint on this patient which wouldn't normally be my first choice um and we opted to change this bandage weekly so these radio Buffs you can see here were taken 12 weeks post-operatively and these ones were taken at 19 weeks post-operatively and we can see that there's much better bone density to the radius here but ulna has started to get a little bit thicker here as well and so we've got resolution or resolving um older and radius atrophy and osteopenia here um and this patient was then cautiously and gradually returned back to exercise now the reason for including this case in our case studies is that there are some really important lessons to be learned here um the first is that if you've got a toy breed patient with a distal radial fracture absolutely locking technology is suitable for that type of fracture configuration but it's very useful to warn owners that we may need to perform serial radiography just to assess any kind of stress protection in this patient we could see a three-week post-operative radiographs already that we had stress protection there um but it wasn't until seven weeks post-operatively that that patient was referred over to me if you're suspicious that there is stress protection in fracture early intervention is really really recommended to dynamize the implant construct to make sure that it's not so stable that it's um causing stress protection osteopenia and atrophy of those bones now there are a number of basic mistakes that were made repairing this fracture um the Locking System that was selected for this fraction configuration wasn't completely appropriate um this was a transverse simple fracture that could have been compressed and and should have been compressed so a dynamic locking plate rather than a purely locking plate without any mode of compression would have been more appropriate a smaller plate would have been more appropriate as well the plate that was used was um was far too big for this patient um you could have easily used a dynamic locking plate with a monoaxial angle stable system um in this patient there's sufficient bone stock distally here that you shouldn't need to be angling screws away from the 5Cs or the fracture line so it wasn't necessary to select the polyaxial system that was used in this instance so the take-home message really from this case study is that locking technology is really really useful um and can be applied to lots and lots of different fracture configurations but proper planning of proper fracture planning as you would with any other fracture system is really really important in order to have the best possible outcomes for patients so if you possibly can compress a fracture it should be compressed um and you need to have a think about whether you're going to be using a monoaxial system or whether a polyaxal system really is necessary and in a vast majority of patients you'll find that a dynamic clocking plate is actually the most versatile um for fracture fixation so as we've already said in summary proper fracture assessment and repair planning are still vital locking technology can be really useful in certain clinical situations um and it's versatile enough to be applied to almost any fracture I know that I've said it a lot of times before in this webinar but always place your cortical screws first and your locking screws last um consider the advantages when you're doing your fracture planning of reconstruction reconstructing a fracture compared to repairing it without disturbing a soft tissue and vasculature and just bear in mind that locking technology is useful for more minimal approaches if it's appropriate to use a more minimal approach and not to disturb your fracture site and that's the end thank you for your time have you got any questions thanks Nikki that was um that was great very uh comprehensive so thank you very much um I think we do have some questions Stella's been monitoring the Q a um Stella yes hello everybody I've just got a few questions to go through um so I'll kick it off with this one can a novice surgeon start out using locking plates or would you recommend getting experience with DCPS first it's a really good question I think um DCPS provide you with quite a good grounding in terms of um making sure that you are used to contouring plates accurately because you have to do that with a DCP but novice surgeons absolutely could start out with locking technology as well for sure as long as you plan your fracture appropriately as you would have to with the DCP and plan which kind of implants you're going to use as well um as you would have to with the DCP then yeah I think it would be perfectly reasonable for another surgeon to to start with locking technology great thank you and if you are able to purchase just one Locking System in the whole world what would it be I think I would probably say a dynamic locking Plate System rather than a polyaxial system um that's probably the most versatile system to purchase in your first instance you can apply it to fractures that you wish to compress you can use the plates to Aid in reduction of fractures or you can use the plates just in buttressing bridging fashion so you don't have to apply cortical screws at all so I think that's probably going to be the most versatile uh Locking System to use okay thank you and lastly do you know oral brands of locking plates and screws compatible with each other or do they vary it's a really good question so the answer to that is no they're not all compatible um it's really important to have a look at the manufacturer instructions um I think that we know from having done some testing um in the lab that we've looked at um screws that are supposed to be compatible with different systems and actually their screw threads are completely different so um I think to be on the safe side I would suggest that once you've purchased a system you use just those screws um but if you're really desperate to Interchange your screws then you need to be checking with the manufacturer as to whether there's compatibility or not great thank you that was everything oh sorry there might be one more there's one more would you advise cancerless bone grass with the toy breed distal radial fractures um it's a good question I think that if you've got a fracture that you can compress so you've reconstructed your fracture nicely and you can compress actually your bone graft is probably not entirely necessary if you have got a more comminuted fracture one that you can't compress or can't reconstruct accurately or you're running into bother with um a delayed Union or a non-union then absolutely grafting would be what I would suggest there we go and not a question but thank you for a nice presentation from Mohammed welcome Muhammad excellent thanks ever so much Nikki that's been um that's been a really good um presentation I I hope everyone agrees that's given you a really thorough um overview so many thanks again for your time um as I said at the beginning you will all receive uh via Euro vets uh webinar recording link so you can watch the webinar back again and you will also receive again via Euro vets uh CPD certificate for your time this evening and I'm also going to send out um a link for a feedback form which we would love if you would um fill in so uh Veterinary instrumentation hasn't historically been a provider of webinars This Is A New Concept um to us and we really truly uh want to know what you think um so I'm gonna send out a link to a feedback form I haven't decided yet whether that's going to come from me or via that's I think probably via Euro vets in the next few days um so if you could just take a couple of minutes to fill in the feedback form we would genuinely be really grateful because we do want to know um what our customers think um so I think that's a wrap thank you ever so much again Nikki for your time and thank you ever so much to everyone who's um who spent their time with us this evening I can see a few thank yous coming in I hope you've enjoyed it we'll see you all again thanks a lot bye hi everyone

2023-04-20 20:39

Other news