The Epidemiology and National Trends of Bearing Surface Usage in Primary Total Hip Arthroplasty in Korea

윤필환,유정준,김윤정,유승미,이상훈,김희중 대한정형외과학회 2016 Clinics in Orthopedic Surgery Vol.8 No.1

Background: We analyzed the data for primary total hip arthroplasty (THA) in the Korean nationwide database to assess (1) the epidemiology and national trends of bearing surface usage in THAs and (2) the prevalence of each type of bearing surface according to age, gender, hospital type, primary payer, and hospital procedure volume. Methods: A total of 30,881 THAs were analyzed using the Korean Health Insurance Review and Assessment Service database for 2007 through 2011. Bearing surfaces were sub-grouped according to device code for national health insurance claims and consisted of ceramic-on-ceramic (CoC), metal-on-polyethylene (MoP), ceramic-on-polyethylene (CoP), and metal-on-metal (MoM). The prevalence of each type of bearing surface was calculated and stratified by age, gender, hospital type, primary payer, and procedure volume of each hospital. Results: CoC was the most frequently used bearing surface (76.7%), followed by MoP (11.9%), CoP (7.3%), and MoM (4.1%). The proportion of THAs using a CoC bearing surface increased steadily from 71.6% in 2007 to 81.4% in 2011, whereas the proportions using CoP, MoP, and MoM bearing surfaces decreased. The order of prevalence was identical to that in the general population regardless of age, gender, hospital type, primary payer, and hospital procedure volume. Conclusions: The trends and epidemiology of bearing surface usage in THAs in Korea are different from those in other countries, and the CoC bearing surface is the most prevalent articulation. In future, the results of a large-scale study using nationwide data of THAs involving a CoC bearing surface will be reported in Korea.

Femoral Head Fracture without Dislocation by Low-Energy Trauma in a Young Adult

윤필환,Hyun Seok Jeong,유정준,구경회,윤강섭,김희중 대한정형외과학회 2011 Clinics in Orthopedic Surgery Vol.3 No.4

We describe the case of a healthy young man with a femoral head fracture by low-energy trauma that occurred without evidenceof hip dislocation. While plain radiographs showed no defi nite fracture or dislocation, computed tomography (CT) and magneticresonance imaging (MRI) revealed a femoral head fracture with a wedge-shaped cortical depression at the superomedial aspectof the femoral head. Our patient reported feeling that the right hip had been displaced from its joint for a moment. This probablyrepresented subluxation with spontaneous relocation. The characteristic fi ndings and possible mechanisms of this fracture werepostulated on the basis of the sequential 3 dimensional-CT and MRI. The clinical results of conservative treatment were betterthan those of previously reported indentation fractures.

Cementless Total Hip Arthroplasty for Patients with Crowe Type III or IV Developmental Dysplasia of the Hip: Two-Stage Total Hip Arthroplasty Following Skeletal Traction after Soft Tissue Release for Irreducible Hips

윤필환,김중일,Dong Ok Kim,Cheol Hwan Yu,유정준,김희중,윤강섭 대한정형외과학회 2013 Clinics in Orthopedic Surgery Vol.5 No.3

Background: Total hip arthroplasty (THA) for severe developmental dysplasia of the hip (DDH) is a technically demanding procedure for arthroplasty surgeons, and it is often difficult to reduce the hip joint without soft tissue release due to severe flexion contracture. We performed two-stage THAs in irreducible hips with expected lengthening of the affected limb after THA of over 2.5 cm or with flexion contractures of greater than 30 degrees in order to place the acetabular cup in the true acetabulum and to prevent neurologic deficits associated with acute elongation of the limb. The purpose of this study is to evaluate the outcomes of cementless THA in patients with severe DDH with a special focus on the results of two-stage THA. Methods: Retrospective clinical and radiological evaluations were done on 17 patients with Crowe type III or IV developmental DDH treated by THA. There were 14 women and 3 men with a mean age of 52.3 years. Follow-ups averaged 52 months. Six cases were treated with two-stage THA followed by surgical hip liberalization and skeletal traction for 2 weeks. Results: The mean Harris hip score improved from 40.9 to 89.1, and mean leg length discrepancy (LLD) in 13 unilateral cases was reduced from 2.95 to 0.8 cm. In the patients who underwent two-stage surgery, no nerve palsy was observed, and the single one-stage patient with incomplete peroneal nerve palsy recovered fully 4 weeks postoperatively. Conclusions: The short-term clinical and radiographic outcomes of primary cementless THA for patients with Crowe type III or IV DDH were encouraging. Two-stage THA followed by skeletal traction after soft tissue release could provide alternative solutions to the minimization of limb shortenings or LLD without neurologic deficits in highly selected patients.

Epidemiology of Hip Replacements in Korea from 2007 to 2011

윤필환,이영균,안정훈,장은진,김윤정,곽홍석,윤강섭,김희중,유정준 대한의학회 2014 Journal of Korean medical science Vol.29 No.6

We analyzed national data collected by the Health Insurance Review and AssessmentService in Korea from 2007 to 2011; 1) to document procedural numbers and proceduralrate of bipolar hemiarthroplasty (BH), primary and revision total hip arthroplasties (THAs),2) to stratify the prevalence of each procedure by age, gender, and hospital type, andquantified, 3) to estimate the revision burden and evaluate whether the burden is changedover time. Our final study population included 60,230 BHs, 40,760 primary THAs, and10,341 revision THAs. From 2007 to 2011, both the number and the rate of BHs, primaryTHAs increased steadily, whereas there was no significant change in revision THAs. Overthe 5 yr, the rate of BHs and primary THAs per 100,000 persons significantly increased by33.2% and 21.4%, respectively. The number of revision THAs was consistent over time. The overall annual revision burden for THA decreased from 22.1% in 2007 to 18.9% in2011. In contrast to western data, there were no changes in the number and rate ofrevision THAs, and the rates of primary and revision THAs were higher for men than thosefor women. Although 5 yr is a short time to determine a change in the revision burden,there have been significant decreases in some age groups.

전주시 유통산업발전법으로 인한 갈등사례

윤필환 한국갈등학회 2017 한국갈등학회보 Vol.3 No.1

LKAS의 실도로 안전성 평가방법에 관한 연구

윤필환,이선봉 사단법인 한국자동차안전학회 2018 자동차안전학회지 Vol.10 No.4

Recently, the automobile industry has developed ADAS (Advanced Driver Assistance System) to prevent traffic accidents and reduce driver's driving burden. Among the ADAS, the LKAS (Lane Keeping Assistance System) is a support system for the convenience and safety of the driver, and the main function is to maintain the driving lane of the vehicle. LKAS is a system that uses radar sensor and camera sensor to collect information about the position of the vehicle in the lane and to support keeping the lane through control if necessary. In many countries, LKAS has already been commercialized and the convenience and safety of drivers have been improved. The international LKAS evaluation test procedure is being developed and discussed by standardization committees such as the ISO (International Organization for Standardization) and the Euro NCAP (New Car Assessment Program). In Korean, the LKAS test method is specified in the KNCAP (Korean New Car Assessment Program), but the evaluation method is not defined. Therefore, the LKAS test procedure that meets international standards and is suitable for domestic road environment is necessary. In this paper, development of LKAS test evaluation scenarios that meets international standards and considering domestic road environment, and the formula that can evaluate the result value after control as the relative distance of lane and the front wheel are suggested. And a comparative analysis was conducted to verify the validity of the suggested scenario and formula. The test evaluation was conducted using the vehicle equipped with the LKAS.

Zn의 첨가량이 다이캐스팅용 ADC12 알루미늄 합금의 특성변화에 미치는 영향 (초)

윤필환,손현진,임관우,권용재,이광학,김용현,박주열 대한금속재료학회 ( 구 대한금속학회 ) 2008 대한금속재료학회 학술대회 개요집 Vol.2008 No.1

Subchondral Insufficiency Fracture of the Femoral Head in Elderly People

윤필환,곽홍석,유정준,윤강섭,김희중 대한의학회 2014 Journal of Korean medical science Vol.29 No.4

We evaluated the clinical course of subchondral insufficiency fracture of the femoral head(SIFFH) and its characteristic findings with special regard to joint space narrowing (JSN). Thirty-one cases of SIFFH of mean age 68.9 yr initially underwent limited weight-bearingconservative treatment. During the follow-up period, the patients with intractable painunderwent total hip arthroplasty (THA). For radiographic evaluation, lateral center-edgeangle, JSN and femoral head collapse (FHC) were documented, and the extent of FHC wasclassified as mild (< 2 mm), moderate (2-4 mm), and severe (> 4 mm). The progression ornew development of FHC more than 2 mm was evaluated on sequential plain radiographs. The relationship between radiographic parameters and clinical outcomes were evaluated. THAs were performed in 15 cases (48.4%). There was no significant correlation betweenclinical outcomes and the extent of initial FHC. However, a significantly larger proportionof patients that underwent THA showed JSN and FHC progression compared to thesymptom improvement group. The risk factor significantly associated with failedconservative treatment was JSN (P = 0.038; OR, 11.8; 95% CI, 1.15-122.26). Clinicalresults of conservative treatment for SIFFH in elderly patients are relatively poor. Thepatients with JSN are at higher risk of failed conservative treatment.

Aspergillus Septic Arthritis of the Hip in an Immunocompetent Middle-aged Female with Undiagnosed Recurrent Pulmonary Aspergillosis

윤필환,송주호,윤강섭,장재석,김희중,유기형 대한고관절학회 2015 Hip and Pelvis Vol.27 No.3

We present a case of Aspergillus septic hip arthritis in an immunocompetent patient with undiagnosed recurrent pulmonary aspergillosis who underwent arthroscopic surgery. Biopsy specimens of synovium revealed fungal hyphae, confirming Aspergillus infection. Aspergillus septic hip arthritis can occur in immunocompetent patients, and arthroscopy can be a noninvasive surgical option in these cases.

결합 링 반사기 레이저 다이오드의 광대역 파장 가변 및 변조 특성 해석

윤필환,김수현,정영철,Yoon, Pil-Hwan,Kim, Su-Hyun,Chung, Young-Chul 한국광학회 2006 한국광학회지 Vol.17 No.6

본 논문에서는 기존의 DBR 격자 기반의 파장선택성 반사기를 대체시킬 수 있는 결합 링 반사기가 집적된 레이저 다이오드를 연산자 분리 시 영역 모델을 통해서 분석한다. 결합 링 반사기는 브래그 격자(Bragg grating) 필요로 하지 않는 평판 도파로 형태의 반사기이다. 결합 링 반사기는 하나의 직선 도파로와 두 개의 결합된 형태의 링 공진기가 하나의 직선 도파로에 결합되어 있다. 위상 조절 전류의 조절에 따른 파장 가변 범위는 수십 nm 정도가 되고, 파장 가변 과정에서 부모드 억압비도 35 dB 이상이 됨을 수치 해석을 통해 확인했다. 또한 결합 링 반사기 레이저 다이오드는 종래의 레이저 다이오드에 비해서 유효 공진기 길이(Effective Cavity Length)가 매우 길기 때문에 진폭 변조 시 20-30 GHz 주파수 영역에서 추가적인 공진 특성을 보이고, 이 특성으로 인해 진폭 변조 대역폭이 상당히 향상될 수 있으리라 기대된다. A time-domain modeling approach is used to study characteristics of a widely tunable coupled-ring reflector (CRR) laser diode(LD). The CRR consists of a bus waveguide and two coupled ring resonators coupled to the bus without resorting to distributed Bragg grating structure. The tuning range can be a few tens of nanometers with a side mode suppression ratio exceeding 35dB through the adjustment of currents into the phase control sections in the rings. The CRR laser diode has long effective cavity length compared to conventional laser diodes. Accordingly, a broad additional resonance peak in the amplitude modulation characteristics is observed between 20 to 30 GHz, implying the extension of amplitude modulation bandwidth.