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Featured researches published by Yougun Won.


Journal of Bone Metabolism | 2014

Atypical Femoral Fracture Combined with Osteonecrosis of Jaw During Osteoporosis Treatment with Bisphosphonate

Yougun Won; Joon-Ryul Lim; Young-Hwan Kim; Hyung-Keun Song; Kyu Hyun Yang

Bisphosphonate, a potent anti-resorptive agent, is generally accepted as a safe, effective, well tolerated treatment for postmenopausal osteoporosis. Atypical femoral fracture (AFF) and bisphosphonate related osteonecrosis of jaw (BRONJ) are the increasing morbidities in patients treated with long term bisphosphonate. Pathogenic mechanisms of AFF and BRONJ are not fully identified and not identical. We report a case of BRONJ followed by AFF and its nonunion in a 67-year-old woman patient receiving an oral bisphosphonate during 7 years for the treatment of osteoporosis.


American Journal of Emergency Medicine | 2014

Assessment of Bosworth-type fracture by external oblique radiographs.

Kyu Hyun Yang; Yougun Won; Joon-Ryul Lim; Dong-Hyun Kang

INTRODUCTION Bosworth described an unusual fracture dislocation of the ankle with fixed posterior fracture dislocation of the fibula. This ankle fracture variant is often not recognized in initial radiographs and requires a computed tomographic scan for verification. It is usually not reducible by the closed method, and repeated trials induce more damage. The purpose of this study was to verify the usefulness of simple external oblique radiographs for diagnosis of Bosworth-type fracture. METHODS We reviewed the 327 patients who were diagnosed as unilateral malleolus ankle fracture in 2002 to 2012. Four cases of Bosworth-type fracture were identified. External oblique radiograph was taken initially, immediately after first closed reduction, and after open reduction (3 phases) was undertaken to check the position of fibula in relation with the talus. Fifty cases of bimalleolar fractures and unaffected ankle were compared. Longitudinal bisecting line along the proximal fibula was drawn, and the talus was divided in 2 parts. Anterior and posterior part of the talus was defined as part α and β. The ratio resulted from dividing α with (α + β) implies the fibula position relative to the talus. RESULTS Mean α/(α + β) ratio of each phase were 0.4994, 0.4891, 0.2875, 0.2698, and 0.2709. There was significant difference in initial and first reduction phase of Bosworth-type fracture than other groups (P = < .0001). There was no significant difference in open reduced Bosworth-type fracture with bimalleolar fractures and unaffected ankles (P = .528, .602). CONCLUSIONS An external oblique radiograph provides useful information that can differentiate Bosworth-type fracture from other reducible bimalleolar fractures.


Journal of Orthopaedic Trauma | 2015

Role of Appositional Screw Fixation in Minimally Invasive Plate Osteosynthesis for Distal Tibial Fracture

Kyu-Hyun Yang; Yougun Won; Dong-Hyun Kang; Jin-Cheol Oh; Sungjun Kim

Objectives: To determine the effect of interfragmentary appositional (gap-closing) screw fixation in minimally invasive plate osteosynthesis (MIPO) for distal tibial fractures on the clinical and radiologic results. Design: Prospective nonrandomized study. Setting: Level I trauma center. Patients: Sixty patients who were diagnosed as distal metadiaphyseal oblique or spiral tibial fracture without displaced articular fragment. Intervention: Thirty patients (group A) of the 60 patients were treated with MIPO without appositional screw fixation, and the other 30 (group B) were treated with the screw. Main Outcome Measurements: Radiologic union, clinical union, clinical functional score [American Orthopaedic Foot and Ankle Society (AOFAS) score], and complications. Results: The time for initial callus formation and radiologic union was significantly longer in group A than those in group B (76.8 vs. 58.0 days, P = 0.044; 409 vs. 258.7 days, P = 0.002, respectively). The rate of clinical union during 1 year was significantly higher in group B than in group A (P = 0.0063). Four nonunion patients in group A achieved bone union after placement of an additional bone graft. None of the patients in group B diagnosed with delayed union or nonunion (P < 0.001). None of the patients of both groups had malreduction, skin problems, or infection. Overall, the AOFAS score did not significantly differ between groups A and B (85.4 vs. 87.0, P = 0.43). Conclusions: The use of additional interfragmentary appositional screw fixation in distal tibia MIPO for the fixation of oblique or spiral fracture promoted callus formation and union rate compared with MIPO without appositional screw fixation. Level of Evidence: Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.


Journal of Foot & Ankle Surgery | 2017

Comparison of Time to Operation and Efficacies of Ultrasound-Guided Nerve Block and General Anesthesia in Emergency External Fixation of Lower Leg Fractures (AO 42, 43, 44)

Chan Kang; Sang-Bum Kim; Youn-Moo Heo; Yougun Won; Byung-Hak Oh; June-Bum Jun; Gi-Soo Lee

&NA; The present randomized controlled trial evaluated the usefulness of ultrasound (US)‐guided nerve block (NB) for emergency external fixation of lower leg fractures, by investigating the time required before surgery and the clinical results stratified by the anesthesia method (US‐guided NB or general anesthesia [GA]). From June 2014 to April 2016, 40 patients who had undergone emergency surgery for external fixator application were enrolled in the present study. We measured the lead time before the start of surgery after the decision to perform emergency surgery in both groups. The US‐guided NB group included 17 males (85%) and 3 females (15%), with a mean age of 55.6 (range 33 to 77) years. Of these 20 patients, 12 (60%) had comorbidities such as diabetes mellitus, hypertension, and kidney‐related disease. Fracture type 42, 43, and 44 in the AO classification were observed in 3 (15%), 12 (60%), and 5 (25%) cases, respectively. The mean interval before emergency surgery was 4.3 (range 2 to 6.25) hours in the US‐guided NB group. In the GA group (n = 20 patients), the mean interval before emergency surgery was 9.4 (range 3 to 14) hours, and this difference was statistically significant (p < .001). In the US‐guided NB group, no cases of anesthesia failure or unstable vital signs occurred during surgery. Also, no postoperative complications related to the anesthesia method, such as aggravation of the general condition, developed. In contrast, 1 case of postoperative atelectasis occurred in the GA group. Emergency external fixation with US‐guided NB in patients with lower extremity trauma can be implemented in less time, regardless of the preoperative preparation, which is a requirement for GA. &NA; Level of Clinical Evidence: 4


Journal of Bone Metabolism | 2015

Comparison of the Chemical Composition of Subchondral Trabecular Bone of Medial Femoral Condyle between with Advanced Osteoarthritis and without Osteoarthritis

Kwang Kyoun Kim; Yougun Won; Tae Gyun Kim; Myong Hyun Baek; Jaewon Choi

Background The purpose of this study is to investigate differences of chemical composition between subchondral bone in advanced osteoarthritic (OA) and non-OA distal femur. Methods Twenty femurs were harvested, respectively. The subchondral trabeculae were obtained from the middle of medial articular surface of distal femurs. A 10 mm diameter cylindrical saw was used to harvest. Raman spectroscopy, a non-destructive technique, was employed to determine the chemical information of the trabecular bones in the human distal femurs. Results The maximum intensity of the phosphate peak was 2,376.51±954.6 for the non-OA group and 1,936.3±831.75 for the OA group. The maximum intensity of the phosphate peak observed between the two groups was significantly different (P=0.017). The maximum intensity of the amide I peak were 474.17±253.42 for the nonOA group and 261.91±205.61 for the OA group. The maximum intensity of the amide I peak were significantly different between the two groups (P=0.042). Also, among other chemical and matrix components (Hydroxyproline,Carbonate, Amide IIIdisordered;ordered, and CH2), the spectrums showed similar significant differences in the intensity (P=0.027, P=0.014, P=0.012; P=0.038, P=0.029). Area integration were performed to determine disorder in collagens secondary structure via amide III (alpha helix/random coil). The value of the alpha helix to random coil band area are significantly different (P=0.021) and result showing that there was a trend toward higher collagen maturity for the nonosteoarthritic bone specimens. Conclusions The result suggested that OA may affect the chemical compositions of trabecular bone, and such distinctive chemical information may be.


Foot and Ankle Surgery | 2017

Comparison of postoperative pain control methods after bony surgery in the foot and ankle

Chan Kang; Gi-Soo Lee; Sang-Bum Kim; Yougun Won; Jeong-kil Lee; Yousun Jung; Hyung-June Cho

BACKGROUND We performed a prospective study to evaluate and compare the effectiveness of postoperative pain control methods after bone surgery in the foot and ankle. METHODS Among the patients who underwent foot and ankle surgery from June 2014 to September 2015 with an ultrasound-guided nerve block, 84 patients who fully completed a postoperative pain survey were enrolled. An opioid patch (fentanyl patch, 25mg) was applied in group A (30 patients). Diluted anesthetic (0.2% ropivacaine, 30ml) was injected into the sciatic nerve once, about 12h after the preoperative nerve block, in group B (27 patients). Periodic intramuscular injection of an analgesic (ketorolac [Tarasyn], 30mg) was performed in group C (27 patients). The visual analogue scale (VAS) pain scores at 6, 12, 18, 24, and 48h after surgery were checked, and the complications of all methods were monitored. RESULTS The mean VAS pain score was lower in group B, with a statistically significant difference (P<.05) between groups A, B, and C at 12 and 18h after surgery. Four patients in group A experienced nausea and vomiting; however, no other patients complained of any complications or adverse effects. CONCLUSION The ultrasound-guided injection of a diluted anesthetic into the sciatic nerve seemed to be the most useful method for controlling pain in the acute phase after bone surgery in the foot and ankle. The injection of the diluted anesthetic once on the evening of the day of surgery resulted in less postoperative pain in the patients. LEVEL OF EVIDENCE II.


Yonsei Medical Journal | 2016

The Efficacy of Low Molecular Weight Heparin for the Prevention of Venous Thromboembolism after Hip Fracture Surgery in Korean Patients

Kwang-Kyoun Kim; Yougun Won; Ye-Yeon Won

Purpose The aim of this study was to investigate the efficacy of low-molecular-weight heparin (LMWH) for the prevention of venous thromboembolism in Korean patients who underwent hip fracture surgery (HFS). Materials and Methods Prospectively, a total 181 cases were classified into the LMWH user group (116 cases) and LMWH non-user group (65 cases). Each group was sub-classified according to fracture types as follows: 81 cases of intertrochanteric fracture (group A: 49, group B: 32) and 100 cases of neck fracture (group C: 67, group D: 33). We compared the incidence of deep vein thrombosis (DVT) and pulmonary embolism (PE) according to LMWH use. Results Of the 181 cases, four DVTs were found in the LMWH user groups (1 in group A, and 3 in group C). One case of PE was found in LMWH non-user group D. The incidences of DVT and PE showed no statistically significant differences between the LMWH user and non-user groups (p=0.298 and 0.359, respectively). In subgroup analysis, no statistically significant differences were found between groups A and B and between groups C and D. Conclusion The administration of LMWH was not effective in the prevention of venous thromboembolism and PE in the Korean patients who underwent HFS.


Yonsei Medical Journal | 2016

Osteochondral Autograft from the Ipsilateral Femoral Head by Surgical Dislocation for Treatment of Femoral Head Fracture Dislocation: A Case Report

Yougun Won; Gi Soo Lee; Sang Bum Kim; Sun Joong Kim; Kyu Hyun Yang

As anatomical reduction of the articular surface of femoral head fractures and restoration of damaged cartilage are essential for good long-term results, many treatment options have been suggested, including fixation of the fracture using various surgical exposures and implants, as well as arthroscopic irrigation and debridement, bone marrow stimulating techniques, osteochondral allograft, autograft, and autogenous chondrocyte implantation. We report a case of osteochondral autograft harvested from its own femoral articular surface through surgical hip dislocation. The osteochondral graft was harvested from the inferior non-weight-bearing articular surface and grafted to the osteochondral defect. One year later, the clinical and radiological results were good, without the collapse of the femoral head or arthritic change. This procedure introduced in our case is considered convenient and able to lessen surgical time without morbidity of the donor site associated with the harvest.


Foot & Ankle Orthopaedics | 2018

Screw fixation of the posterior malleolar fracture: An experimental and prospective clinical study

Gi-Soo Lee; Chan Kang; Byung-Ki Cho; Yougun Won

Category: Trauma Introduction/Purpose: Posterior malleolar fracture is known to be an indication for surgery when the size of the fragment is greater than 25% to 30% of the joint surface. The purpose of this study was to compare the results of cannulated screw fixation and early joint motion in patients with ankle fracture with posterior malleolar fracture of less than 25%, and we do cadaver experiments. Methods: The clinical portion of the study evaluated 70 patients with fracture of the posterior malleolus that comprised less than 25% of the articular surface. After fixation for lateral and/or medial malleolar fractures, cannulated screw fixation was performed for posterior malleolar fractures in 34 cases. (A group) In other 36 cases, fixation was not performed for posterior malleolar fractures. (B group) One week after the operation, ankle range of motion exercise was performed. Cadaver studies were evaluated both cannulated screw fixed and non-fixed in less than 25% fractures of the posterior malleolar. The stability of the ankle joint was measured in 12 cases. In 6 cases, the posterior malleolar was fixed and the other 6 cases were not fixed. Results: There was no significant difference in clinical outcome between Group A and B and functional score at 2 years follow up. However, the ankle function score at 6 months and 1 year after the follow - up was significantly higher in group A than in group B. In the cadaver study, the group with screw fixation was significantly stable in external rotation. Conclusion: In case of less than 25% posterior fracture, screw fixation is considered to have a significant effect on recovery and clinical outcome in the short term due to stability.


Spine | 2017

Unilateral Spinous Process Noncovering Hook Type Patient-specific Drill Template for Thoracic Pedicle Screw Fixation: A Pilot Clinical Trial and Template Classification

Sang B. Kim; Yougun Won; Hyun jin Yoo; Lee J. Sin; John M. Rhee; Sang W. Lee; Gi-Soo Lee

Study Design. Prospective clinical pilot study. Objective. To confirm the accuracy of thoracic pedicle screw placement by using the unilateral spinous noncovering hook type patient-specific drill template (PSDT) made through rapid prototyping (RP) and to analyze previously reported PSDT designs and their characteristics. Summary of Background Data. Pedicle screw fixation is the most common form of the posterior instrumentation of the thoracic and lumbar spine. Various techniques have been introduced to improve pedicle screw placement. Among them PSDT with a preplanned trajectory has been considered a promising solution; however, we don’t have consensus on proper character of the template. Methods. Preoperative spiral three-dimensional (3D) computed tomography (CT) was performed on the thoracic spine. The images were stored in DICOM format and transferred to a workstation running MIMICS 17.0 software to generate a 3D reconstruction template for the desired thoracic vertebra. The accurate trajectory and screw diameter and length were calculated with UG Imageware 12.1. The guide template was sterilized and used intraoperatively to assist with the placement of thoracic pedicle screws. After all pedicle trajectory screws had been inserted. We reviewed 12 previous reports and classified them according to the shape and system of PSDT that met the inclusion criteria of the review. Results. Ten screws were placed by using the PSDT without violating the single laminar cortex. There was no violation of the spinal canal or the cortex of pedicle on postoperative CT scans. The results of 13 PSDT types included in the current study suggested that there is no significant difference in accuracy between the PSDTs. Conclusion. The unilateral spinous process noncovering hook type PSDT made through RP provided an accurate trajectory for the thoracic vertebra, and the classification of PSDT in this study could be helpful for further studies. Level of Evidence: 5

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Chan Kang

Chungnam National University

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