• Korean Journal of Computational Design and Engineering
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• v.18 no.6
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• pp.385-398
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• 2013

Opening wedge high tibial osteotomy (OWHTO) is widely used to treat unicompartmental osteoarthritis of the knee caused by degenerative deformations of the anatomical axes of the leg. However, since it is difficult to accurately plan the surgical degrees of adjustment such as coronal correction angle and tibial posterior slope angle to align the axes before the actual procedure, a number of studies have proposed analytical models to solve this problem. While previous analytical models for OWHTO were limited to specific cases, this study proposes an analytical osteotomy model (AOM) and a surgical planning system (SPS) that are suitable for a wide range of tibial morphologies and tibia conditions. The validity and generality of the model were verified in a total of 60 OWHTO cases. Results of the test showed that, as predicted, surgical degrees are affected quite significantly by tibia shape and slope of the resected surface. Comparison of the required surgical degrees and the degrees estimated from virtual surgery simulations using AOM showed a very small average difference of $0.118^{\circ}$. SPS, based on AOM, allows the operating surgeon to easily calculate surgical parameters needed to treat a patient.

• Proceedings of the KSME Conference
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• 2008.11a
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• pp.1543-1546
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• 2008

The purpose of this study was to investigate factors affecting the change of tibial posterior slope and introduce a mathematical model which calculate, through 3-dimensional analysis of the proximal tibia, how the angle of the opening wedge along the anteromedial tibial cortex influences the tibial posterior slope and valgus correction when performing a medial open wedge osteotomy. This mathematical model with navigation system can be guidelines which provide surgeons on preoperative and intraoperative measurements to maintain or correct the tibial slope and to obtain the desired valgus correction of the lower limb during an opening wedge osteotomy.

• 대한관절경학회:학술대회논문집
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• 2007.10a
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• pp.97-98
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• 2007

• Knee surgery & related research
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• v.30 no.4
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• pp.364-368
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• 2018

We report a case of 53-year-old woman with an injured popliteal artery due to excessive drilling with a drill bit during medial opening wedge high tibial osteotomy (MOWHTO). Pseudoaneurysm was diagnosed three days after surgery and confirmed by urgent computed tomography (CT) angiography. Open vascular surgery with resection of the perivascular hematoma and end-to-end anastomosis using ipsilateral saphenous vein interposition graft was performed. CT angiography at 8 months postoperatively showed that blood flow was maintained without obstruction of the graft site and active dorsiflexion of the foot was possible. To reduce neurovascular injury during MOWHTO, it is important not to drill the far cortex at the proximal part of the osteotomy site when using a drill bit, and the metal should be positioned posteromedially as much as possible.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.35 no.8
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• pp.835-846
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• 2011

In medial opening wedge high tibial osteotomy (OWHTO), researchers have reported critical problems caused by unexpected changes in the tibial posterior-slope angle. This unexpected change can be analyzed, but there is no general solution for cases with an oblique hinge axis and cut plane. We propose a general analysis model for OWHTO. We first evaluate the effects according to variation in the hinge axis and tibial cut plane and then define an ideal correction axis. This ideal axis, called the virtual tibial correction axis, is not on the tibial cut plane in general. In this paper, we also present an evaluation of feasibility of the proposed analysis model.

• Proceedings of the KSME Conference
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• 2008.11a
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• pp.1467-1470
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• 2008

An upper tibial opening wedge osteotomy is an operation to cure a malalignment and a degenerate arthritis. To prevent the postoperative malalignment caused by the upper tibial opening wedge osteotomy, the research to define the relationship between a Hinge Axis Angle and a Posterior Slope Angle is needed. The effect of the relationship between the hinge axis angle and the gap angle on the posterior slope angle is studied. After 3-D Compute Tomography (CT) scanning image is reconstructed, the virtual surgery is performed by the reconstructed 3-D tibia model. It was proved that the relationship between the hinge axis angle and the gap angle were constant and the simple mathematical model could be derived. To verify the suggested mathematical model, it compared with the measured data from the virtual surgery. In conclusion, while the deviation between the data from the virtual surgery and ones of the mathematical model under the gap angle<$10^{\circ}$ was less than 1%.

• Journal of the Korean Orthopaedic Association
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• v.54 no.2
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• pp.120-126
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• 2019

Purpose: The efficacy of periarticular multimodal drug injection and adductor canal block after a medial opening-wedge high tibial osteotomy was compared in terms of the postoperative pain level. Materials and Methods: From November 2016 to March 2017, 60 patients underwent a medial opening-wedge high tibial osteotomy under spinal anesthesia. Preemptive analgesic medication, intravenous patient controlled anesthesia were used for pain control in all patients. Thirty patients received a periarticular multimodal drug injection (group I), and 30 patients received an adductor canal block (group II). These two groups were compared regarding the postoperative pain level, frequency of additional tramadol injections, total amount of patient-controlled analgesia, and number of times that the patients pushed the patient-controlled analgesia button at each time interval. Results: The visual analogue scale scores over the two-week postoperative period showed no statistical significance. The frequency of additional tramadol hydrochloride injections was similar in the two groups over time. The mean number of times that patients pushed the patient-controlled analgesia button was similar in two groups over time. The total amount of patient-controlled analgesia was similar in the two groups over time. Conclusion: This study shows that intraoperative periarticular multimodal drug injections and adductor canal block may have a similar effect on postoperative pain control in patients who have undergone a medial opening-wedge high tibial osteotomy for unicompartmental osteoarthritis of the knee.

• Journal of the Korean Orthopaedic Association
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• v.55 no.2
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• pp.127-134
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• 2020

Purpose: The aims of this study were (1) to investigate the relationship between the characteristics of allogenic bone block and the compressive strength of an allogenic bone block measured by biomechanical experiments, and (2) to compare the maximum pressure load of allogenic bone block with the gap pressure measured at the high tibial opening osteotomy. Materials and Methods: Ten patients who provided informed consent for gap pressure measurements during opening wedge high tibial osteotomy (OWHTO) were included. The gap pressures were measured at 1 mm intervals while opening the osteotomy site from 8 mm to 14 mm. Seventeen U-shaped allogenous wedge bone blocks were made from the femur, tibia, and humerus. The height, width, cross-sectional area, and cortex thickness of the bone blocks were measured, along with the maximum compressive load just before breakage. The relationship between these characteristics and the maximum pressure load of the bone blocks was evaluated. The gap pressures measured in OWHTO were compared with the maximum pressure loads of the allogenous wedge bone blocks to evaluate the possibility of inserting allogenous wedge bone blocks into the osteotomy site without a distractor in OWHTO. Results: The OWHTO gap pressure increased with increasing osteotomy site opening. The mean gap pressure, which occurred at a 14-mm opening, was 282±93 N; the maximum pressure was 427 N. The maximum pressure load of the allografts was 13,379±6,469 N (minimum, 5,868; maximum, 29,130 N) and was correlated significantly with the cortical bone thickness (correlation coefficient=0.693, p=0.002) and cross-sectional area (correlation coefficient=0.826, p<0.001). Depending on the sterilization method, the maximum pressure loads for the bone blocks were 13,406±5,928 N for freeze-dried and 13,348±7,449 N for fresh frozen. The maximum compressive load of the allogenous wedge bone blocks was 13.7-times greater than that in OWHTO opened to 14 mm (5,868 N vs. 427 N). Conclusion: The compressive strength of allogenous wedge bone blocks was sufficiently greater than the gap pressure in OWHTO. Therefore, allogenous wedge bone blocks can be inserted safely into the osteotomy site without a distractor.

• 대한관절경학회:학술대회논문집
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• 2009.10a
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• pp.192-192
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• 2009

• Transactions of the Korean Society of Mechanical Engineers B
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• v.36 no.3
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• pp.351-361
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• 2012

The leading surgical method for correcting the misalignment of the varus and valgus in the knee joint is the high tibial osteotomy (HTO). In the opening wedge HTO (OWHTO), there is no concern about damaging the peroneal nerve on the lateral tibia of the proximal fibula. OWHTO has been the preferred choice, as the opening of the correction angle can be modulated during the operation. The correction of the varus and valgus on the coronal plane are performed adroitly. Nevertheless, there have been numerous reports of unintended changes in the medial tibial plateau and posterior slope angle (PSA). The authors have developed an HTO method using computer-assisted surgery with the aim of addressing the abovementioned problems from an engineer's perspective. CT images of the high tibia were reconstructed three-dimensionally, and a virtual osteotomy was performed on a computer. In addition, this study recommends a surgical method that does not cause changes in the PSA after OWHTO. The results of the study are expected to suggest a clear relationship between the anteromedial cortex oblique angle of each patient and the PSA, and an optimal PSA selection method for individuals.