• 대한족부족관절학회지
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• 제25권4호
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• pp.185-189
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• 2021

An aneurysmal bone cyst (ABC) can occur in many parts of the human body, but a primary ABC of the talus is extremely rare. ABCs are benign, but aggressively growing tumors that usually occur in the first two decades of life. Patients mainly complain of pain, limited movement of the involved joint or a palpable mass. Pain may worsen suddenly because of pathological fractures. If not treated properly, ABC has a risk of local recurrence, followed by the destruction of the joint and a significant functional deficit. While the complete removal of the bone tumor is essential, it is also important to treat the resultant bone defect after removal. The talus has an important part to play in weight-bearing. Therefore, an appropriate bone graft is required for large bone defects that occur after an ABC removal from the talus. We report a primary ABC of the talus in a 28-year-old male that was treated by curettage and a bone pillar pattern graft of autologous tricortical iliac crest bone. The patient had an excellent functional outcome with early weight-bearing, and there was no recurrence at 16 months of follow-up.

• 한국소음진동공학회논문집
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• 제23권2호
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• pp.131-143
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• 2013

대부분의 철강산업 기계 등에 설치되어 사용되는 선회베어링은 교체를 위한 정확한 정비계획이 필요하기 때문에 저속회전체의 선회베어링에 대한 진동 상태감시가 매우 중요하게 되었다. 지금까지 음향방출(AE)법이 저속베어링의 상태감시에 가장 많이 사용되는 기술이고 몇몇의 경우는 진동을 사용한다. 음향방출을 사용하는 일반적인 이유는 저속에서 구름요소와 결함위치 사이의 충격에 의하여 발생되는 신호가 약하고 때때로 노이즈나 다른 간섭 주파수에 결함신호가 묻혀 검출이 어렵기 때문이다. 따라서 쉽게 특정 결함에 대한 결함주파수의 동정을 위하여 몇몇 연구자들은 충격에너지를 증가시키기 위하여 인위적으로 미리 정해진 길이, 넓이와 깊이의 결함을 베어링의 내, 외부 레이스에 인가하기도 한다. 이 논문에서는 15 rpm에서 운전하는 저속 선회베어링의 진동신호에 EMD와 EEMD를 적용하였고 논문에서 사용한 진동결함 신호는 국내 산업체에서 공급받은 것이다. 이 논문에서는 베어링결함 주파수 동정을 위하여 EEMD를 사용하여 결함신호의 FFT처리 결과를 입증하고 설명하였다.

• Journal of the Korean Wood Science and Technology
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• 제33권1호통권129호
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• pp.7-16
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• 2005

본 연구에서는 국산 낙엽송 부재를 이용한 이중 볼트 전단 접합부의 성능을 평가하였다. 주부재로 두께 39 mm, 89 mm, 139 mm, 189 mm로 제재된 국산 낙엽송 제재목과 국산 낙엽송으로 제조된 두께 80 mm, 140 mm, 170 mm 집성재를 사용하였으며, 측면 부재로는 동일 두께의 제재목과 6 mm 철판을 사용하였으며, 접합 철물로는 M12, M16, M20 볼트를 사용하였다. 접합부에 대한 하중 방향은 주부재와 측면 부재의 목리 경사에 대해 수직, 수평한 경우에 대하여 실시하였다. 다우얼 지압 강도 실험을 통해 부재의 다우얼 지압 강도를 산출하고, 볼트 휨 실험을 통해 볼트의 휨 강도를 구한뒤, 최종 볼트 접합부 실험을 통해 접합부 성능을 평가하였으며, 최종 결과는 EYM (European Yield Model)을 사용한 계산값과 비교 평가하였다. 연구 결과 국산 낙엽송 부재의 이중 전단 볼트 접합부 성능은 EYM을 사용하여 얻어진 계산값과 비교하였을 때 그에 상응하거나 그 이상임을 알 수 있었으며, 특히 측면 부재가 제재목인 경우는 거의 일치함을 알 수 있었다. 파괴 모드는 옹이나 건조 결함 등의 영향을 많이 받으며 주부재의 두께가 작을 경우는 mode I, 주부재가 커짐에 따라 mode III으로 옮겨감을 알 수 있었다.

• Archives of Plastic Surgery
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• 제32권4호
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• pp.441-446
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• 2005

Sole reconstruction should consider both functional and aesthetic aspects; durable weight bearing surface, adequate contour for normal footwear, protective sensation and solid anchoring to deep tissue to resist shearing. The anterolateral thigh perforator free flap has such favorable characteristics as long pedicle, reliable perforators and minimal donor site morbidity. This flap can be safely thinned to 3-4 mm. It can also be elevated with sufficient bulk with muscles like vastus lateralis for complex defect. Between June 2002 and December 2004, 48 cases of sole reconstruction were performed with anterolateral thigh perforator free flaps. Follow up period ranged from 4 to 34 months with a mean of 14.7 months and with exception of one case, all flaps survived. One case of total flap loss was noted due to infection in a patient who was administered lifetime immunosuppressant. Partial necroses developed in three cases but were treated conservatively. Satisfactory aesthetic and functional results were achieved and acceptable gait recovery was noted. Seventy-eight percent of the patients regained protective sensation by 6 months and earlier sensory recovery was noted in sensate flap group. The authors also present a standardized protocol for preoperative patient evaluation and postoperative management and rehabilitation.

• 한국재료학회:학술대회논문집
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• 한국재료학회 2011년도 춘계학술발표대회
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• pp.53.2-53.2
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• 2011

Ti metal has superior mechanical properties along with biocompatibility, but it still has the problem of bio-inertness thus forming weaker bond in bone/implant interface and long term clinical performance as orthopaedic and dental devices are restricted for stress shielding effect. On the other hand, despite the excellent biodegradable behavior as being an integral constituent of the natural bone, the mechanical properties of ${\beta}$-tricalcium phosphate $(Ca_3(PO_4)_2;\;{\beta}-TCP)$ ceramics are not reliable enough for post operative load bearing application in human hard tissue defect site. One reasonable approach would be to mediate the features of the two by making a composite. In this study, ${\beta}$-TCP/Ti ceramic-metal composites were fabricated by spark plasma sintering in inert atmosphere to inhibit the formation of $TiO_2$. Composites of 30 vol%, 50 vol% and 70 vol% ${\beta}$-TCP with Ti were fabricated. Detailed microstructural and phase characteristics were investigated by FE-SEM, EDS and XRD. Material properties like relative density, hardness, compressive strength, elastic modulus etc. were characterized. Cell viability and biocompatibility were investigated using the MTT assay and by examining cell proliferation behavior.

• 한국안전학회지
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• 제15권2호
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• pp.1-7
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• 2000

This paper presents the approach involving fault detection and diagnosis of gears using pattern recognition and Wavelet transform. It describes result of the comparison between KDI (Kullback Discrimination Information) with the nearest neighbor classification rule as one of pattern recognition methods and Wavelet transform to know a way to detect and diagnosis of gear damages experimentally. To model the damages 1) Normal (no defect), 2) one tooth is worn out, 3) All teeth faces are worn out 4) One tooth is broken. The vibration sensor was attached on the bearing housing. This produced the total time history data that is 20 pieces of each condition. We chose the standard data and measure distance between standard and tested data. In Wavelet transform analysis method, the time series data of magnitude in specified frequency (rotary and mesh frequency) were earned. As a result, the monitoring system using Wavelet transform method and KDI with nearest neighbor classification rule successfully detected and classified the damages from the experimental data.

• Archives of Reconstructive Microsurgery
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• 제3권1호
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• pp.54-63
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• 1994

Pulp and palm of the hand and heel of the sole are anatomically unique. Satisfactory reconstruction of these areas presents the plastic surgeon with many challenges and requires durable and sensible skin coverage, minimal donor morbidity and reliable operative procedure. We presents 7 clinical cases of sensate instep free flap transfer in this paper during the last 2 years. Three cases were soft tissue defects due to crushing and avulsion injury on the pulp of finger. 1 case was unstable scar and redundant flap after reconstruction of soft tissue dect of palm and 1 case was contracture of first web of hand. One case was a soft tissue defect due to avulsion injury on heel. Lastly, one case was chronic osteomyelitis with open wound on lateral malleolar area. Follow-up period ranged from 3 months to 2 years. Through the whole follow-up period, all flaps were viable and durable to persistant stress or weight bearing and were sensible enough to porotect the recocstructed area from injuries and maintain functions. In conclusions, the instep free flap should be considered as a valuable tool in reconstruction of hand and extremity requiring durability and sensation.

• 대한족부족관절학회지
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• 제23권4호
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• pp.208-211
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• 2019

Diabetic foot ulcers can progress to the point where amputation is needed, and so these ulcers require active treatment. Skin grafts or flaps can be performed for coverage of this type of ulcer. Local flap surgery is relatively easy to perform and good results have been previously reported. We performed single-lobed rotation flap on 5 cases of forefoot ulcer around the site of weight bearing. The location of the foot ulcers was the medial part of the first metatarsophalangeal joint in all the patients. The mean size of the defect was 4.70 ㎠. Managing of ulcers, controlling of diabetes and infection, and improving of peripheral blood flow were performed before surgery. In two cases, infection progressed to the articular cartilage and so metatarsophalangeal joint fusions were performed simultaneously. All the cases were completely transplanted. There was no recurrence of the ulcers, and all the patients were able to walk.

• 대한두개안면성형외과학회지
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• 제21권3호
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• pp.184-187
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• 2020

Scalp reconstruction is challenging because the scalp is inelastic, stiff, and has hair follicles. Tissue expansion offers aesthetically pleasing outcomes with minimal donor-site morbidity. However, in a scarred scalp, the extent of possible dissection for the expander insertion may be limited and surgeons must make use of the limited scalp tissue. We successfully reconstructed scarred scalps using rectangular expanders. This report presents two cases: a 4×3 cm chronic defect with widespread scarring and osteomyelitis and an 11×7.5 cm scar tissue following a skin graft. Tissue expanders were inserted in the subgaleal plane and were inflated by 195 mL and 400 mL over periods of 2 and 3 months, respectively. Subgaleal elevation of a fasciocutaneous flap was achieved with the expanded tissue. The defects were well covered, with good color, texture, and hair-bearing tissue. There were no complications involving the tissue expanders. Rectangular expanders yield more available tissue than round or crescent-shaped expanders. Moreover, since the base of the flap is well defined, the expander can be easily inserted in a limited space. Therefore, rectangular expanders are recommended for the reconstruction of scarred scalps.

• Archives of Reconstructive Microsurgery
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• 제15권1호
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• pp.17-25
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• 2006

Twelve cases in eleven patients with segmental bone defects were treated with contralateral fibula free flap and ipsilateral island fibula flap in an antegrade, retrograde or bidirectional flow fashion. Five cases were managed with free flaps and seven were with ipsilateral fibula island transfer. Among seven cases, antegrade fashion was three, retrograde was three, and bidirectional was one. All patients were related with open tibial fractures and its sequelae except one who had open foot bone fracture. According to Gustilo's classification, ten patients were type IIIb and one was type IIIc. Basically, antegrade-flow flaps based on the peroneal vessels as in the conventional free flap were used for the proximal or middle one-third tibial defects. On the contrary, retrograde-flow flaps based on the communicating branch between the peroneal and posterior tibial vessels were used for the middle or distal one-third of the tibia. Bidirection-flow flap based on intact peroneal vessels were used for the middle portion of the tibia. The patients who have undergone ipsilateral fibula island flap had one of the following problems: a previously failed free flap, below-knee amputation of the opposite leg because of open tibial fracture, refusal to use the contralateral sound leg, or poor general condition to stand a lengthy operation. Six of the patients who have got ipsilateral fibula island flap also had an associated fibula fracture on the same leg, which was ultimately used as one of the osteotomy sites. The follow-up period was from 1 to 10 years. Two cases of free flap were failed: one patient had below-knee amputation and the other patient had ipsilateral fibula transfer. Other cases were successful and excellent hypertophy of the transferred fibula was achieved. Time to bone union ranged from 4 to 11 months. Time to full weight bearing was from 5 to 13 months after surgery. All of the transferred fibulas showed hypertrophy after weight bearing. In one case, stress fracture was developed during ambulation, which was healed conservatively. Nonunion occurred in two cases, which were treated with a long leg cast and cancellous bone graft, respectively. Length discrepancy of the legs was noted. The limb was shorter by an average 0.5 cm in three cases, longer by 1.1 cm in one case. In the case of island fibula transfer, limited arc of rotation was not a problem. Other disabling complications were not seen. We believe that these diverse modalities using a vascularized fibula will make us more comfortable to handle major bone defects.