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ROBUST FAULT TOLERANT CONTROL SYSTEM USING ADAPTIVE SCHEMES
Ahn, Chung-Il,Kim, You Dan 서울대학교 항공우주신기술연구소 2001 항공우주신기술연구소 연구보고 Vol.2 No.2
In this paper, robust fault detection and isolation algorithm is proposed using the adaptive scheme. The fault detection and isolation scheme proposed is robust with respect to the unstructured uncertainties such as signal noise, parameter variation, and modeling error. The time-varying uncertainty is considered, and it is assumed that the characteristics of uncertainty are unknown. The fault tolerant control system is designed to make the failed system follow the model outputs updated by the adaptive rule to minimize the effects of faults. The robust analysis of the proposed control system is performed via Lyapunov approach. To validate the proposed adaptive fault tolerant control algorithm, numerical simulation is performed using VTOL aircraft system.
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전재균,전태현,윤자영,정덕희,안충한 대한정형외과학회 2019 Clinics in Orthopedic Surgery Vol.11 No.4
Background: We investigated whether the patellar tilt angle influences the maximum knee flexion after total knee arthroplasty (TKA) performed by using a posterior cruciate ligament-substituting (PS) fixed-bearing prosthesis in patients with relatively loose or tight flexion gap. Methods: In this prospective cohort study, we followed up 169 patients for at least 2 years after TKA using PS fixed-bearing prosthesis. The patients were divided into two groups according to the flexion gap value—calculated by subtracting the thickness of the final bearing from the flexion gap measured intraoperatively under 200-cN·m force after patellar reduction and insertion of the final femoral and tibial components—into a relatively tight group (group T; 3–6.5 mm) and a relatively loose group (group L; 7–11 mm). Patellar tilt angles and maximum non–weight-bearing active knee flexion angles were assessed postoperatively. Group T was further divided into subgroup Tn if the patellar tilt angle was < 5° and subgroup Tw if the angle was ≥ 5°. Pearson correlation test was used for the correlation analysis of the flexion gap, patellar tilt angle, and postoperative flexion range. Results: The mean postoperative flexion was 137.3° in group T and 137.5° in group L. The mean patellar tilt angle was 6.5° in group T and 6.9° in group L. In group T, a strong negative correlation (r = –0.78, p < 0.05) was observed between the patellar tilt and postoperative flexion range. However, further analysis revealed that only the subgroup Tw showed a strong negative correlation (r = –0.76, p < 0.05). Significant correlations were not found in the subgroup Tn and group L. Conclusions: In TKA where a relatively tight flexion gap (≤ 6.5 mm) is created because of concerns about postoperative flexion instability due to a loose flexion gap, the patellar tilt angle should be < 5° for maximal postoperative knee flexion.
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상완 삼두근 측-측 견인 도달법을 통한 AO/OTA 분류C2형 원위 상완골 관절내 골절의 치료
이철형,선두훈,정덕희,안충한 대한골절학회 2019 대한골절학회지 Vol.32 No.3
Purpose: The aim of this study was to determine the outcomes of fixation of AO/OTA type C2 fractures among intra-articular fractures of the distal humerus using the paratricipital approach (side to side retraction of the triceps). Materials and Methods: From June 2008 to January 2018, 12 patients underwent an open reduction and internal fixation with the paratricipital approach and were followed-up for more than 10 months after surgery. According to the AO/OTA classification, type C2 fractures were chosen among the intraarticular distal humerus fractures. An extended posterior incision was used over the olecranon in the prone position, preserving the insertion site of the triceps brachii muscle. The fracture site was exposed by retracting the muscle side-to side through a dissection of the medial and lateral intermuscular septum of the triceps brachii muscle. The therapeutic results were assessed by the anatomical reduction of the articular surface and integrity of the metaphyseal contour in postoperative simple radiographs, complications, such as neuropathy or non-union, and the Mayo elbow performance score (MEPS) were checked to estimate the functional outcome. Results: In the postoperative simple radiographs, no case showed more than 1 mm step-off and the disrupted contour of the distal humerus was recovered to normal alignment in most cases. The range of elbow joint motion in the last follow-up was 133.8° on average with a mean flexion contracture of 5.0°. The clinical results depending on the MEPS were excellent, except for two cases, which were good. Neuropathy of the ulnar nerve was observed in one patient, which was resolved after metal removal. Conclusion: The paratricipital approach is useful technique in AO/OTA type C2 intra-articular distal humerus fractures that provides sufficient exposure of the surgical field, without injury to the triceps brachii muscle and postoperative complications associated with the trans-olecranon approach. 목적: 원위 상완골 골절 중 AO/OTA 분류 C2형에서 상완 삼두근 측-측 견인 도달법의 유용성을 알아보고자 하였다. 대상 및 방법: 2008년 6월부터 2018년 1월까지 상완 삼두근측-측 견인 도달법을 이용하여 관혈적 정복술 및 내고정술을 시행한 환자들 중 최소 10개월 이상 추시 가능했으며 AO/ OTA 분류 C2형에 해당하는 총 12예를 대상으로 하였다. 수술은 주관절 후방 중앙 절개 후 삼두근 원위 부착부에 손상을 주지 않고 내외측을 박리한 후 양측으로 견인하며 수술 시야를 확보하였다. 치료 결과는 술 후 해부학적 정복 시행 여부 평가 및 추시 시 골유합 여부, 합병증 유무와 함께 MEPS 를 사용한 주관절의 기능 평가를 바탕으로 분석하였다. 결과: 술 후 단순 방사선 사진에서 모두 해부학적 정복이 확인되었다. 주관절 가동 범위는 평균 133.8°, 굴곡 구축은 평균 5.0°를 보였다. MEPS를 사용한 기능 평가에서 우수 10예, 양호 2예의 임상 결과를 보였으며 1예에서만 척골 신경병증이 발생하였다. 결론: 상완 삼두근 측-측 견인 도달법은 AO/OTA 분류 C2 형 원위 상완골 골절 수술 시 시야 확보에 문제되지 않았으며합병증 발생이 적다는 점에서 좀 더 적극적으로 적용시킬 수있다고 평가된다.
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송인수,정덕희,정의탁,안충한 대한정형외과학회 2019 Clinics in Orthopedic Surgery Vol.11 No.4
Background: Glenoid loosening and postoperative instability are common causes of failed reverse total shoulder arthroplasty (RTSA). When soft-tissue problems or large glenoid bone defect interferes with reimplantation in revision RTSA, conversion to hemiarthroplasty can be considered. We present a case series of patients who underwent conversion to hemiarthroplasty due to glenoid loosening and early instability after RTSAs, along with clinical results. Methods: A total of 72 primary RTSAs using the Aequalis prosthesis were performed at our institution from May 2009 to December 2016. Of these, five patients, including one with humeral neck fracture and absent rotator cuff and four with cuff tear arthropathy, underwent conversion to hemiarthroplasty. Another patient who had RTSA at a local clinic underwent hemiarthroplasty at our institution for unresolved postoperative anterior dislocation. The mean age of the six patients was 71.7 years (range, 62 to 76 years), and the mean follow-up period was 24.4 months (range, 18 to 30 months). Clinical assessments were conducted by using the visual analog scale (VAS), American Shoulder and Elbow Surgery (ASES) score, and University of California at Los Angeles (UCLA) shoulder score at the last follow-up. Results: The conversion to hemiarthroplasty in the six patients dramatically improved the mean VAS score (preoperative, 8.1; postoperative, 2.5), ASES score (preoperative, 22.1; postoperative, 56.5), and UCLA score (preoperative, 12; postoperative, 18.1). However, the range of motion was almost unchanged after surgery. Conclusions: Conversion to hemiarthroplasty can be a good alternative to revision RTSA in patients with serious complications (such as unresolved instability and glenoid loosening) difficult to treat with revision RTSA
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요골 원위부 골절 환자에서 정형외과 의사가 시행한 초음파 유도 액와 상완 신경총 차단술
선두훈,이철형,김철우,정덕희,안충한 대한수부외과학회 2019 대한수부외과학회지 Vol.24 No.2
Purpose: The purpose of this study was to evaluate the usefulness of ultrasound-guided axillary brachial plexus block performed by orthopedic surgeon as an anesthetic method for distal radius fracture surgery.Methods: From October 2017 to October 2018, an ultrasound-guided axillary brachial plexus block was performed on 161 cases of distal radius fracture requiring surgery. The procedure was performed by orthopedic surgeons using solution (20 mL of lidocaine HCl in 2%, 20 mL of ropivacaine in 0.75%, and 10 mL of normal saline in 0.9%). The success rate of the anesthetic procedure, the duration of analgesic effect, and the complications were investigated. If the anesthesia induc-tion failed, additional local anesthetic methods were performed stepwise and reassessment about whether the operation could proceed was made.Results: Anesthesia was successful in 155 patients and the success rate was 96.3%. The duration of analgesic effect was 6 hours (3-10 hours). In 6 failed cases of anesthesia, local anesthesia was applied to the pain site in the operating room. In 5 cases, the operation was completed without discomfort. In 1 case complaining of pain around fracture site after the local anesthesia, ultrasound-guided radial nerve block was effective in controlling the pain.Conclusion: In open surgery of distal radius fractures, an ultrasound-guided axillary brachial plexus block performed by orthopedic surgeon allows anesthesia with high success rates. Even if the surgical anesthesia is incomplete, it is expected that the surgery cab be completed safely if the nerve is identified and the stepwise additional local anesthesia method is performed. 목적: 요골 원위부 골절 수술 시 정형외과 의사가 시행한 초음파 유도 액와 상완 신경총 차단술의 유용성에 대하여 알아보고자 한다.방법: 2017년 10월부터 2018년 10월까지 요골 원위부 골절 수술 전 마취 방법으로 초음파 유도 액와 상완 신경총 차단술을 시행한 161명을 대상으로 하였다. 2% lidocaine HCl 20 mL, 0.75% ropivacaine 20 mL, 0.9% nor-mal saline 10 mL의 혼합액을 이용하였으며 술기의 성공률, 무통 지속 시간 및 합병증을 조사하였다. 술기가 실패한 경우 단계적으로 추가 국소 마취를 시행한 뒤 재평가하였다. 결과: 161명 중 155명에서 마취가 성공하여 96.3%의 성공률을 보였다. 무통 지속 시간은 평균 6시간(3-10시간)이었다. 6명이 마취 실패로 수술실에서 통증 부위에 국소 마취제를 추가 투여하였으며 5명은 이후 환자의 불편감 없이 수술을 마칠 수 있었고, 1명은 초음파 유도 요골 신경 차단술을 통해 수술을 완료할 수 있었다.결론: 요골 원위부 골절 수술 시 정형외과 의사가 시행한 초음파 유도 액와 상완 신경총 차단술은 높은 마취 성공률을 보였고, 마취가 불완전 하더라도 해당 신경을 파악하여 단계적 추가 국소 마취 방법을 시행한다면 안전하게 수술을 완료할 수 있을 것으로 기대한다.
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불안정성 원위 요골 골절의 치료에 있어 한국형 이중 연골하 지지고정 전방 금속판의 임상적 및 방사선학적 결과
이철형(Chul-Hyung Lee),정덕희(Deukhee Jung),안충한(Chung-Han An),정의탁(Uitak Jeong) 대한정형외과학회 2020 대한정형외과학회지 Vol.55 No.6
목적: 본 연구는 요골 원위부 골절에 대해 국내에서 이중 연골하 지지고정 개념으로 개발된 전방 잠김 금속판의 수술 후 정복 유지효과 및 이에 영향을 줄 수 있는 요인들에 대해 평가해 보고자 하였다. 대상 및 방법: 2017년 7월부터 2018년 12월까지 요골 원위부 골절 환자 중 관혈적 정복 및 금속판 고정술을 시행한 54예를 대상으로 하였다. 수술 직후와 최종 추시 시 촬영한 단순방사선 사진을 이용해 요골 길이, 요골경사, 수장측 경사, 척골 변위, 원위 배측 피질 거리(distal dorsal cortical distance)를 측정하여 골절 정복 유지 효과에 대해 평가하였다. 환자 나이, 골절 분류, 금속판 위치를 기준으로 전체 환자군을 세부 그룹으로 나누어 비교함으로써 각 요인이 골절 정복 유지에 미치는 영향을 분석하였다. 결과: 수술 직후 원위 배측 피질 거리는 평균 5.91 mm (표준 편차, ±1.95 mm)로 측정되었으며 요골 길이(p=0.038), 척골 변위(p=0.001)는 수술 직후와 최종 추시 시 촬영한 단순 방사선 사진에서 유의한 차이가 확인되었다. 전체 환자군을 각 요인에 따라 세부 그룹으로 나누어 평가했을 시 척골 변위는 나이가 65세 이상이거나 AO/OTA 분류 C3형에 해당하는 경우 혹은 금속판 위치가 Soong classification grade 0에 해당하는 경우 수술 직후에 비해 최종 추시 시 유의하게 증가하였다(p=0.007, p=0.012, =p0.046). 결론: 국내에서 이중 연골하 지지고정 개념으로 생산된 전방 잠김 금속판을 이용하여 요골 원위부 골절 정복술을 시행하는 경우 충분한 정복을 확보할 수 있으며 골절 정복 유지에 대해 전반적으로 긍정적인 결과를 보이나, 환자가 고령인 경우, 관절 내 골절의 분쇄 정도가 심한 경우, 금속판이 분수령선의 근위부에 위치한 경우에 척골 변위의 증가를 보여 요골 월상골와의 정복 유지를 위한 고려가 필요하다. Purpose: The aim of this study was to assess the effectiveness of domestically developed volar locking plate which has the concept of double-tiered subchondral support (DSS) in maintaining the reduction after distal radial fracture surgery. Materials and Methods: From July 2017 to December 2018, 54 patients were assessed. Plain radiographs were obtained immediately after surgery and at the last follow-up, and the radiographic parameters were measured in those images: radial length, radial inclination, volar tilt, ulnar variance, and distal dorsal cortical distance. The patients were subdivided into their age, type of fracture, and the position of the plate to evaluate the influence of each factors on the reduction maintenance. Results: Distal dorsal cortical distance in radiographs after the surgery was 5.91 mm (standard deviation, ±1.95 mm) on average. Significant differences in the radial length (p=0.038) and ulnar variance (p=0.001) were observed between immediately after surgery and at the last follow-up. When the parameters were evaluated by dividing the patients into subgroups according to the three specific factors, the ulnar variance showed a significant increase at the last follow-up when the patients were included 65-years-old or older. AO/OTA type C3 fracture, and Soong classification grade 0 plate position (p=0.007, p=0.012, p=0.046, respectively). Conclusion: Using the domestically developed DSS-type volar locking plate, significant reduction after distal radial fracture surgery could be maintained successfully. On the other hand, further study will be needed to determine about the reduction loss of the lunate facet identified in special cases that deal with fractures in elderly patients, unstable AO/OTA type C3 distal radial fractures, and Soong classification grade 0 plate position.
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