Hello, I'm Al Getgood. I'm an orthopaedic surgeon at the Fowler Kennedy Sport Medicine Clinic in London, Ontario, Canada. And I'm going to be talking to you about indications and extended indications for osteotomy around the knee. These are my disclosures, none of which are relevant for this topic. Okay, as an overview, we're going to be talking about what we're trying to achieve with osteotomy and then going through some of the indications both on a pathology basis and patient factors, and then where we should exercise caution. And then I'm going to give you some illustrative case examples. So first off, we're going to think about is the biomechanics of gait. And this just looking at the coronal plane, and you can see that this patient has got a varus thrust on the left hand side. And what is actually happening here? Well, if you think that the centre of mass is coming from L5 S1, that's on foot placement and stance phase creates a ground reaction force. And this ground reaction force is a certain distance away from the centre of rotation of the knee, which creates an adduction moment. So an adduction moment, and that is counteracted by the soft tissues on the outside of the knee. So if there's any laxity in the soft tissues, that's what creates this varus thrust. So the adduction moment is due to the medial foot placement. It's a surrogate measure of medial compartment load. You get increased varus due to a lax postologic corner and you develop this varus thrust. And so what we're trying to achieve with coronal plane correction is to reduce the external knee adduction moment in the varus knee or an abduction moment in the valgus knee. And the most common way of doing that of course is to do a proximal tibial osteotomy where the deformity lies most commonly, where there's proximal tibia vera. And the most common procedure these days is a medial opening wedge, HTO, to address the malalignment component. Now we also got to think about what's going on in the sagittal plane and sagittal balance is also very important. And here a very similar concept where you have the center of mass creating a ground reaction force, which is in front of the center of rotation in this scenario where you have hyperextension deformity and that creates an extension moment that's counteracted by the posterior soft tissues. So increased extension moment can be due to a lax posterior capsule. It can also be reduced to a reduced posterior tibial slope. And this creates this hyperextension recurvative thrust. So what's the effect of increasing tibial slope? Well, in stance phase, the axial load moves the tibia anteriorly. So this is an example of a fairly poorly done high tibial osteotomy, which is increasing the tibial slope. And that results in increased anterior tibial translation. So in stance phase, the tibia slides forward, increasing the loads on the ACL. And this has been shown in a number of studies, this one in particular, very nicely demonstrating this linear relationship between graft load and increasing tibial slope. And of course, you have the opposite where you have decreased tibial slope, reduces the graft forces on, sorry, decreasing tibial slope increases graft forces on the PCL. And this has also been shown in a previous study by one of my colleagues, a fellow, Kennedy Bob Giffin, when he was a fellow at Pittsburgh, showing that the impact of a sagittal plane correction and approximately one millimetre of a slope change correction reduces slope by about one degree. Now, we also have to think about our axial alignment. So with normal foot progression, angle remaining fairly consistent and abnormal rotation, in particular, femoral torsion or tibial torsion can significantly impact the forces that are generated around the telephermal joint. And this can cause increased compression on the lateral side and translation with increased shear forces across the cartilage surface. So things we have to think about when we're seeing patients is one, is there a correctable deformity present? And you can just look at a mechanical axis method where you can drop a line from centre hip down to centre of ankle, the so-called Michelet's line. And that really determines as to whether or not there's increased loading on the inside. But really what we should be doing is thinking more of the articulated geometry and doing a full deformity analysis. And there will be other talks during this osteotomy course in terms of what we should be doing to determine this. But essentially, what we're looking for is where is the deformity? And depending on the deformity, that's where the deformity should be corrected. So indications for surgery. So pathology, first of all, on the coronal plane. So we think about osteoarthritis, cartilage repair, cartilage restoration to unload biological tissue. So that would be meniscus transplantations and cartilage restoration. And then, of course, for ligament instability, both medial and lateral as well as the telephermal joint. In the sagittal plane, then we're thinking more about tibial slope. So particularly for ACL and PCL, as previously discussed. And then hyperextension and fixed floor flexion deformities. We can also change the sagittal plane to try and improve the balance of forces around the knee. And then the axial alignment thinking about the telephermal instability and anterior knee pain. So in tackling the complex knee, really, we should be thinking about our biomechanics up front. And that's thinking about realignment to osteotomy before thinking about ligament reconstruction and meniscus allograft transplantation before getting into more biological procedures. And what that really relates to then is that there's so many complex knee pathologies that can be addressed within a form of realignment procedures that can come from chondrosis to tibial femoral OA, meniscal deficiency, through the ligament deficiency, and through the telephermal issues. So osteotomy is a workhorse of the complex knee surgeon. Now, in terms of patient factors that we must think about, well, age does come into it, but we're probably thinking about age and activity level. And then once you get into sort of 55 and older, we may start thinking about a bit of an overlap. But ultimately, what we're looking for, is there a deformity present? And if there's no deformity present, then maybe the patient will be more appropriate for some form of replacement. But in the younger patient, we might be able to push that a little bit harder. And ultimately, what we're trying to do is to stay in this so-called brain zone. And this is a concept from Roman Searle, who really has sort of outlined this idea of trying to keep patients in this sort of more regenerative and preventative process down the bottom end, and then getting into arthroplasty later on. But as soon as you go into the sort of the arthroplasty spectrum, then there's really no turning back. And so osteotomies are an important part of that treatment algorithm. Now, how well do they work? Well, this is data from Fowler Kennedy. We know that osteotomy, that medial opening wedge, high tibial osteotomy has a significant impact in reducing the knee adduction moment. And this correlates very nicely with Kuh scores. And when we look at some subgroup analyses, so males versus females with five and 10 year survivorship, the males tend to do a little bit better in terms of survivorship. When it comes to comorbidities, then we also know that there are certain patients that actually do worse in terms of complications. And we can break down our complications into sort of class one, class two, class three, depending on the amount of treatment that is required. And what we do know is that smoking and diabetics have a higher risk of complications. We have to think about that. Now, we recently did an updated overview of our complications using the Tomofix implant. And here, what we found is very similar findings than the previous results. But smoking certainly associated with a higher risk of overall complications. And we also find really the lateral hinge fracture, so relatively small percentage, but certainly associated with corrections greater than 11 millimeters with minimal number of delayed unions. But one of our biggest issues was hardware removal, okay, with very low rates of infection. Activity level, postoperative goals, again, we have to think about patients, what they want to do, what they want to do postoperatively. This is a study looking at basically osteotomy suggesting that 95% of patients can actually return to sports following a knee osteotomy compared to if we look at patients having either unicompartmental or total knee arthroplasty, it would appear that the unicompartmentals are a little bit better at getting back to sport. Certainly osteotomy do very, very well. So if patients are active and want to get back to sport, then we should probably think about an osteotomy as being a better option. Where should we be cautious? Well, as already mentioned, diabetics and smokers have a higher rate of complication. Peripheral vascular disease and older sedentary females probably don't do as well. And again, if there's no deformity, they're thinking along the lines more of doing some form of arthroplasty. We should also be cautious with fixed flexion deformity. It's not a complete, absolute contraindication, but certainly we don't want to make any deformity worse. And higher grades of osteoarthritis, again, really is very dependent on age and activity level. And that's a shared decision making as to whether or not we should proceed with a joint restoration type procedure with osteotomy joint rather than arthroplasty. But certainly we have shown that patients still can have an extremely good treatment effect from even in stages of Kelvin Lawrence IV severe osteoarthritis, even with correction. And here we have this data showing that with the data showing Kelvin Lawrence II, yes, their survivorship of five and 10 years is better than moderate to severe OA, but you can still see quite a significant treatment effect with 10 year survivorship, upwards of 76%. So that's really pretty impressive data. Now, if you look at the ISSA cost guidelines, they generally hold true today. So this is from a number of years back, but you can see that sort of the ideal and the possible and the not suited. But even if you look at the not suited, you know, doing obese patients, you know, if they're a young patient and they've got a unique or mental disease, we can still do a realignment procedure. We just have to exercise relative caution. So you can extend many of these indications depending on a multitude of factors. And again, as I said before, it's a shared decision-making process. So let's go through some quick cases. So this is a 43 year old with bilateral knee pain, bilateral mild varus alignment. She's fit and healthy. She's very fit and active. She's got moderate disease, particularly in her Rosenberg views. You can see that she doesn't have a huge deformity, but we plan for bilateral high tibial osteotomies with angular stable locking plates for only requiring six millimeter corrections, which would allow early weight bearing and unrestricted return to full sport. This was her planning. And then six weeks post-op, she was walking with no crutches and she was able to teach her first spin class. So very happy with the results. Came back a year later and had the plate removed on the right hand side and had the osteotomy done on the left. A 34 year old family doctor, this is a skiing injury five months previous, caught the edge of her ski, had a varus rotation. She was treated initially non-operatively, but that ultimately failed. She had symptomatic, symptomatic instability. She had asymmetric varus. She had a grade two lockman, grade two pivot, grade two varus, 30 degrees of flexion with a positive dial test. And you can see her stress views showing increased gapping on the lateral side with 2.5 millimeter side to side difference and the asymmetry on her hip, knee, ankle alignment films. So she had a medial opening wedge HTO as well as ACL reconstruction. And in this case, it was fairly low grade of lateral laxity. She did not need anything done to the post-lateral corner. And that was able to reduce her instability very nicely. This is a 21 year old welder with a medial femoral condyle, osteochondritis dissecans. This was previously removed in microfracture, unfortunately continued to have ongoing symptoms. And you can see, although a symmetrical varus alignment, this is now what we describe as pathological varus as his weight bearing axis is within that medial compartment that is symptomatic. And so due to his age and activity level, I did a combined medial opening wedge HTO along with a fresh osteochondral allograft in the same setting. Maybe older patients, we could stage this and just do the osteotomy first and then do the cartilage restoration procedure as the second stage if remaining to be symptomatic. And we know this is important because the large data set from Algros in Toronto showing that patients that didn't have their alignment corrected associated with fresh osteochondral allografts fared worse in terms of the post-operative outcomes. It's a relatively rare case, but something that we can certainly consider. So it's a 22 year old male with a knee dislocation, essentially with a medial joint line tendon that's valgus alignment with a thrust and generalized ligamentous laxity. He's got an ACL, PCL, MCL injury, both clinically and on MRI. You can see this five millimeter side to side difference on his valgus stress radiographs. So he underwent, this is just a planning report. You can see the significant valgus deformity on the femur. So he was ultimately planned out for a correction of his distal femur. So it's just the planning, it's the execution. So distal femoral osteotomy. So we did stage one, the MCL and PCL just because of the managed tunnels and soft tissues, kept him touch weight bearing for six weeks so there wouldn't be increased stress placed on the grafts. And then at stage two, six weeks later did the ACL and a distal femoral osteotomy and he's doing extremely well to this date. 24 year old student had a multiple failed ACL reconstructions, essentially high grade anterior and rotatory knee laxity. You can see on his alignment films that increased anterior tibial translation on the sagittal film, as well as increased posterior tibial slope to 14 degrees with a neutral limb alignment. We know from past studies that 12 degrees of posterior tibial slope has been identified as being a significant risk factor for ACL injury and re-injury. And so we did anterior closing wedge proximal tibial osteotomy at the same time as doing a quad tendon revision ACL reconstruction with a lateral tenodesis and he's actually managed to get back to playing football. 33 year old male had a hyperextension injury to his left knee associated with recurrent patella instability. You can see on his contralateral right-hand side, he had a significant proximal tibial fracture during the same accident, but this ultimately presents with the left knee with a grade three posterior drawer with a grade two MCL positive patella apprehension, but his ACL was stable, very flat tibial slope. So really completing a hyperextension thrust and really struggling, very debilitated by it with neutral limb alignment. You can see here, he's got an increased posterior translation on the left-hand side on his annealing stress fuse. So with that, we did an anterior opening wedge HTO, taking the tubicle off first to enable this a little bit easier, combined it with an MPFL reconstruction, but he was mostly symptomatic from the hyperextension and did an antramedializing tibial tubicle osteotomy after correcting his tibial slope. There's his MPFL, there's some of the intraoperative pictures. We can see that increases his tibial slope and improves his tibial station. And he, again, did very well postoperatively. Deformity can also be on two levels, 34-year-old female with bilateral valgus alignment. So she had significant weight loss, but increasing lateral knee pain and her activity level had reduced. So her planning, you can see her mechanical axis is outside of the knee, but really her planning report shows that she's got deformity in both femur and tibia. So this basically allowed us to plan for a double level correction to maintain, try and maintain her joint line. So this was a medial opening wedge, sorry, medial closing wedge, DFO, and a lateral opening wedge on the tibia. So really, if you're thinking, if you see a mechanical axis outside of the knee, then maybe think about a double level correction. And then two last cases, a 16-year-old with persistent lateral patella instability inflection. So this is a dislocation inflection. She has increased femoral antiversion with a fixed dislocation of the patella there. She's also got coronal plane abnormality. So really quite a complex abnormality. And with her planning, we can see that she has abnormal femoral torsion based on her CT scan. And so to be able to correct in two planes, we took this interesting osteotomy concept of doing an oblique osteotomy in the sagittal plane, and then on rotating, it corrected both axial and coronal planes. We were able to do this over a external fixator to make the correction a little bit more manageable, and then did some soft tissue realignments. And here's, you can see the plane of the osteotomy and the correction that we were able to achieve. This is a 17-year-old girl with bilateral anterior knee pain. So you can see just her standing there, squinting patellae, difficulty with squatting. And when she externally rotates her feet, bringing her knees pointing forward is much easier for her to squat and less painful. A rotational profile shows that she's got an increased foot thigh angle at 90 degrees with increased internal rotation of the femora, suggesting femoral antiversion. And so we get a CT rotational profile, and that shows both femoral and tibial torsion. And so she went in a staged fashion. So the left-hand side first, we did double level rotational corrections, and this is just her postoperatively. You can see even just her Q angle is that much improved. And then at one year post-op, she's doing very well on the left-hand side postoperatively. She's really loading that more on the left-hand side in the gait lab. And so she went back to have her right-hand side operated on. So in summary, realignment osteotomy is vital to achieve a coronal, sagittal, and axial balance in the complex knee. Indications are dependent on pathology as well as patient factors. It's a shared decision as to whether or not she go forward with realignment. And the decision of when and how best to perform this procedure is based on informed discussion of multiple factors, and an appropriate plan should therefore be developed. Thank you very much for your attention.

osteotomy

knee

indications

biomechanical issues

patient factors