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AOSSM 2023 Annual Meeting Recordings no CME
Taking the Load Off: Effect of Varus Producing Dis ...
Taking the Load Off: Effect of Varus Producing Distal Femoral Osteotomy and High Tibial Osteotomy on Compartment Pressures and Contact Area in Varying Stages of Knee Flexion
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Video Transcription
Thanks, Dr. Vidal. My name is Jordan Lyles. I'm from the Arizona Sports Medicine Center. So my study was assessing how various producing femoral and tibial osteotomies affects compartment pressures throughout knee flexion. I have no disclosures. So let's start with the problem. We know that compartment forces are influenced by the limb mechanical axis and that valgus alignment transfers these forces to the lateral compartment, leading to progressive lateral compartment overload. And we know the mechanical overload induces chondrocytes in essence, as well as progressive chondral degeneration with time. We know that in the arthritic valgus knee, this chondral degeneration predominantly affects the posterior aspect of the lateral tibial plateau. And thanks to the research team at UConn, we know that distal femoral osteotomies effectively offload the lateral compartment, but this effect was seen mostly at the anterior femoral cartilage and mostly with the knee in extension. In 1985, we knew that distal femoral osteotomy was unquestionably better than an HTO for valgus deformity. However, when you examine this series, we identify a number of surgical techniques as well as anatomic factors in the HTO group that we know are associated with poor clinical outcomes. So for symptomatic valgus knees, do we know that distal femoral osteotomy is unquestionably better or is this something that we think we know? Long-term clinical outcomes with appropriate patient selection are actually relatively favorable following high tibial osteotomy. And so our study aimed to answer what we should know, which is how compartment pressures and contact areas are influenced by osteotomy location throughout knee flexion. Our study utilized 10 adult unilateral fresh frozen cadavers. Text scan sensors were placed in both compartments to measure pressure. Plates were then positioned and an 8-degree varus correction was made. The native state was then loaded and the specimens were randomized to begin with either the tibial or the femoral-based osteotomy. Pressure and then contact areas were measured at 0, 30, 60, and 90 degrees of flexion. And two-way ANOVA testing was then performed to assess the results. This is a schematic of our test. We did have a custom jig which allowed for independent biplanar adjustment in the coronal as well as the sagittal plane. And these are our testing radiographs showing the native state on the left, the high tibial osteotomy state in the middle, and the DFO state on the right. So we found that after an HTO, the average lateral compartment pressure was significantly reduced at 30, 60, and 90 degrees when compared to the native state, and it was also significantly reduced at higher degrees of flexion when compared to the DFO state. Following DFO, the average lateral compartment pressure returned to near native as flexion increased. The HTO also successfully transferred pressure to the medial compartment at higher flexion angles, and the DFO state showed no significant change at higher flexion angles. Similarly, HTO significantly reduced the lateral compartment peak pressures at higher flexion angles. Again, we saw no significant difference in the DFO state compared to native. And additionally, the medial compartment peak pressures were increased after an HTO. This was significant at 90 and there was no significant difference following distal femoral osteotomy. The lateral compartment contact area was reduced for both osteotomy groups with significant decreases at 90 degrees following high tibial osteotomy. And lastly, I think this is kind of the take-home slide from this, the medial compartment contact area was increased in extension following distal femoral osteotomy, significant and similar to prior studies. But this increase returned to near native as flexion progressed at 30, 60, and 90 degrees. Whereas the HTO state showed a significant increase in extension, however this additional increase remained significant at 30, 60, and 90 degrees when compared both to DFO state as well as the native state. So in conclusion, for corrections of less than 10 degrees in medial closing wedge high tibial osteotomy was more effective at unloading the lateral compartment. And this effect was amplified at higher positions of knee flexion. It does remain critical though that when deciding between an HTO and a DFO, you must carefully assess the patient's anatomy, joint line obliquity, MCL integrity, as well as the medial compartment status. Thank you to Dr. Budall as well as the Stedman Clinic. Thanks. �
Video Summary
In this video, Jordan Lyles from the Arizona Sports Medicine Center discusses a study on how different osteotomies affect compartment pressures in the knee during flexion. The study aimed to determine the effects of osteotomy location on compartment pressures and contact areas in the knee. Through experiments on cadavers, it was found that high tibial osteotomy (HTO) effectively reduced lateral compartment pressure at various degrees of flexion, while distal femoral osteotomy (DFO) showed a return to near-native pressure levels as flexion increased. HTO also transferred pressure to the medial compartment at higher flexion angles. It is important to carefully assess the patient's anatomy and factors when deciding between HTO and DFO. The research team at UConn contributed to prior knowledge on this topic. Credits were given to Dr. Vidal, Dr. Budall, and the Stedman Clinic.
Asset Caption
Jordan Liles
Keywords
Jordan Lyles
Arizona Sports Medicine Center
osteotomies
compartment pressures
knee flexion
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