• Advances in biomechanics and applications
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• v.1 no.3
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• pp.187-210
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• 2014

With the goal of increasing the survivorship of the prosthesis and anticipating primary stability problems of new prosthetic implants, finite element evaluation of the micromotion, at an early stage of the development, is mandatory. This allows assessing and optimizing different designs without manufacturing prostheses. This study aimed at investigating, using finite element analysis (FEA), the difference in the prediction of the primary stability of cementless hip prostheses implanted into a $Sawbones^{(R)}$ 4th generation, using the manufacturer's mechanical properties and using mechanical properties close to that of human bone provided by the literature (39 papers). FEA was carried out on the composite $Sawbones^{(R)}$ implanted with a straight taper femoral stem subjected to a loading condition simulating normal walking. Our results show that micromotion increases with a reduction of the bone material properties and decreases with the augmentation of the bone material properties at the stem-bone interface. Indeed, a decrease of the cancellous Young modulus from 155MPa to 50MPa increased the average micromotion from $29{\mu}m$ up to $41{\mu}m$ (+42%), whereas an increase of the cancellous Young modulus from 155MPa to 1000MPa decreased the average micromotion from $29{\mu}m$ to $5{\mu}m$ (-83%). A decrease of cortical Young modulus from 16.7GPa to 9GPa increase the average global micromotion from $29{\mu}m$ to $35{\mu}m$ (+33%), whereas an increase of the cortical Young modulus from 16.7GPa to 21GPa decreased the average global micromotion from $29{\mu}m$ to $27{\mu}m$ (-7%). It can also be seen that the material properties of the cancellous structure had a greater influence on the micromotion than the material properties of the cortical structure. The present study shows that micromotion predicted at the stem-bone interface with material properties of the $Sawbones^{(R)}$ 4th generation is close to that predicted with mechanical properties of human femur.

• Journal of Veterinary Clinics
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• v.34 no.6
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• pp.454-458
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• 2017

A Maltese (case 1) and a Pomeranian (case 2) presented with acute right and left hind limb weight-bearing lameness. On physical examination, they exhibited severe pain and crepitus on the coxofemoral joint of affected hind limb. In addition, decreased thigh girth measurements were noted compared with the opposite leg. Radiological exam revealed necrotic areas in the femoral head of affected hind limb. These dogs were diagnosed with Legg-$Calv{\acute{e}}$-Perthes disease (LCPD). The dogs underwent micro total hip replacement (THR). After surgery, at 3 years (case 1) and 7 months (case 2), both dogs recovered normal activity. The thigh girth and lameness scores were apparently improved in the affected limbs of both dogs. No complications of prosthesis implants, such as loosening, were noted. The clinical outcomes of these cases indicate that dogs with LCPD can be successfully treated with micro THR and have a good prognosis immediately after surgery.

• Journal of Veterinary Clinics
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• v.33 no.5
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• pp.295-299
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• 2016

A 2-year-old, 1.94 kg spayed female Toy Poodle was referred for revision surgery for patellar reluxation following surgery for bilateral medial patellar luxation (MPL). Intermittent non-weight-bearing lameness of the right hindlimb and weight-bearing lameness of the left hindlimb were evident on general inspection. A physical examination revealed that there was a bilateral grade 4 MPL. On radiographs, the medial and lateral trochlear ridge was bilaterally worn out. Patellar groove replacement (PGR) was performed in two stages to replace the bilateral femoral trochlea that had a severely worn out groove. Corrective femoral osteotomy with increasing anteversion angle, tibial tuberosity transposition, medial releasing, lateral imbrications and PGR were performed on the right hindlimb. Six months after surgery on the right hindlimb, a PGR prosthesis was positioned medially on the frontal plane and tibial tuberosity transposition and lateral imbrications were performed on the left hindlimb. Two weeks after surgery, reluxation of the patella occurred on the left hindlimb. The tibial tuberosity transposition was performed to realign the patella more laterally than the previous surgery, and a patellar sling was applied. Two years after the last surgery, the patient showed no pain on the stifle joint and satisfactory weight-bearing ambulation. Reluxation did not recur. PGR maybe a successful treatment for dogs with iatrogenically damaged and/or worn out patellar grooves.

• Journal of IKEEE
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• v.24 no.3
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• pp.754-765
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• 2020

Currently, Intelligent femoral prostheses that support the corresponding mode in walking and specific movements are being studied. Certain controls such as upstairs, sitting, and standing require a technique to classify control commands based on the user's intention because the mode must be changed before the operation. Therefore, in this paper, we propose a technique that can classify various control commands based on the user's intention in the intelligent thigh prosthesis system. If it is determined that the EMG signal needs to be compensated, the proposed technique compensates the EMG signal using the correlation between the strength and frequency components of the normal EMG signal and the muscle volume estimated by the pressure sensor. Through the experiment, it was confirmed that the user's intention was accurately detected even in the situation where muscle fatigue was accumulated. Improved intention detection techniques allow five control modes to be distinguished based on the number of muscle contractions within a given period of time. The results of the experiment confirmed that 97.5% accuracy was achieved through muscle tone compensation even if the strength of the muscle signal was different from normal due to muscle fatigue after exercise.

• Journal of Chest Surgery
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• v.3 no.2
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• pp.127-132
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• 1970

A patient was 29 year old house wife who was admitted to the Yonsei University Medical Center on 6 th of Nov., in 1970, with chief complaints of complete loss of bilateral visual acuity, generalized weakness, frequent palpitations, claudication of masseter muscles and intermittent fainting. These symptoms were developed 5 years prior to admission. Physical finding on admission revealed complete loss of bilateral visual acuity, absence of both radial and carotid pulse, but there was good femoral and popliteal pulse. She couldn't open her mouth as she desired and had weakness of mastication. Radiological findings of plane chest PA were not significant. Aortogram(Cineangiogram) showed non-visualization of both carotid and subclavian arteries. It showed only innominate and interal mammary artery preoperatively. The operative findings were as follows: There were complete obliterative changes in both common carotid and subclavian arteries, and periarteritis in the innominate artery. Tube Dacron Prosthesis Bypass with V-arm between innominate artery and both common carotid arteries was performed after thromboendarterectomy. Histopathological finding of the thromboend arterectomy specimen was compatible with pulseless disease, which showed marked fibrous thickening of intima and a diffuse inflammatory cell infiltration of the whole layers. Her postopererative course was uneventful. Follow up aortogram(Cineangiogram) was taken on 11th postoperative day, which revealed both common carotid arteries patent. Her preoperative Subjective symtoms disappeared remarkably, such as her visual acuity improved much, fainting and vertigo disappeared completely and she can go to bath room without difficulty and help. Another patient was 34 year old house wife who was admitted on August, 1964 with chief complaints of frequent fainting and progresive visual loss. She was operated only thromboendarterectomy of both common carotid arteries. Postoperative course was smooth and subjective symptoms were disappeared.

• Hip & pelvis
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• v.34 no.4
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• pp.211-218
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• 2022

Purpose: We report on the 10-year clinical hip function and radiologic outcomes of patients who underwent hip arthroplasty using a COREN stem. Materials and Methods: A consecutive series of 224 primary cementless hip arthroplasty implantations were performed using a COREN stem between 2009 and 2011; among these, evaluation of 128 hips was performed during a minimum follow-up period of 10 years. The mean age of patients was 65.4 years (range, 40-82 years) and the mean duration of follow-up was 10.8 years (range, 10-12 years). Evaluation of clinical hip function and radiologic implant outcomes was performed according to clinical score, thigh pain, and radiologic analysis. Results: Dramatic improvement of the mean Harris hip score (HHS) from 59.4 preoperatively to 93.5 was observed at the final follow-up (P≤0.01). Stable fixation was demonstrated for all implants with no change in position except for one case of Vancouver type B2 periprosthetic femur fracture. A radiolucent line (RLL) was observed in 16 hips (12.5%). Thigh pain was observed in only two hips (1.6%) at the final follow-up. There were no cases of osteolysis around the stem. The survival rate for the COREN stem was 97.7%. Conclusion: Good long-term survival with excellent clinical and radiological outcomes can be achieved using the COREN femoral stem regardless of Dorr type.

• Journal of the Korean Orthopaedic Association
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• v.55 no.3
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• pp.244-252
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• 2020

Purpose: Total femoral replacement (TFR) is an extreme form of limb salvage. Considering the rarity of this procedure, reports have focused on the complications and a proper indication is unclear. This study analyzed 36 patients with TFR who were asked the following: 1) prognostic factors related to survival in patients who underwent TFR with a tumoral cause; 2) overall implant and limb survival; 3) complications, functional outcome, and limb status for patients surviving for more than 3 years. Materials and Methods: According to the causes for TFR, 36 patients were categorized into three groups: extensive primary tumoral involvement (group 1, 15 cases), tumoral contamination by an inadvertent procedure or local recurrence (group 2, 16 cases), and salvage of a failed reconstruction (group 3, 5 cases). The factors that may affect the survival of patients included age, sex, cause of TFR, and tumor volume change after chemotherapy. Results: The overall five-year survival of the 36 patients was 31.5%±16.2%. The five-year survival of 31 patients with tumoral causes was 21.1%±15.6%. The five-year survival of 50.0%±31.0% in patients with a decreased tumor volume after chemotherapy was higher than that of increased tumor volume (p=0.02). The five-year survival of 12 cases with a wide margin was 41.7%±27.9%, whereas that of the marginal margin was 0.0%±0.0% (p=0.03). The ten-year overall implant survival of 36 patients was 85.9%±14.1%. The five-year revision-free survival was 16.6%±18.2%. At the final follow-up, 12 maintained tumor prosthesis, three underwent amputation (rotationplasty, 2; above knee amputation, 1), and the remaining one had knee fusion. Among 16 patients with a follow-up of more than three years, 14 patients underwent surgical intervention and two patients had conservative management. Complications included infection in 10 cases, local recurrences in two cases, and one case each of hip dislocation, bushing fracture, and femoral artery occlusion. Conclusion: Patients showing an increased tumor volume after chemotherapy and having an inadequate surgical margin showed a high chance of early death. In the long-term follow-up, TFR showed a high infection rate and the functional outcome was unsatisfactory. Nevertheless, this procedure is an inevitable option of limb preservation in selected patients.

• Archives of Plastic Surgery
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• v.49 no.2
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• pp.184-194
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• 2022

The face and the external nose define an individual's physical appearance. Nasal deformities can cause facial disfigurement along with unwanted psychological repercussions. Nasal deformities range in severity, with the most severe cases being indications for a rhinectomy, due to the complexity of the nasal defect. According to published literature, there is no consensus among otolaryngologists and plastic surgeons on which technique or flap use is preferred in terms of complications, aesthetic outcome, or patient satisfaction. The goal of this study is to provide a comprehensive analysis of published studies on nasal reconstruction following rhinectomy. Using the Preferred Reporting Items for Systematic Review and Meta-Analysis Protocols guidelines for writing systematic reviews, a systematic review was conducted. Four databases were searched using a search strategy. These articles were then imported into the COVIDENCE software and went screening and thorough article review. After screening 2,237 articles, 23 studies were then extracted for data collection analysis. We collected data from 12 case series, 4 case studies, 1 prospective case series, and 4 retrospective chart review studies. The most commonly reported flaps were forehead flaps, superior extended nasal myocutaneous island, forearm free flaps, anterolateral thigh (ALT) free flap, medial femoral condyle free flap (n = 8), and zygomaticus implants (n = 6), and retained nasal prosthesis. Although not specifically indicated by a certain number, the most common indication for the rhinectomy was malignancy, followed by traumas, postsurgical complications, radionecrosis, and congenital nasal malformations.

• Hip & pelvis
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• v.36 no.2
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• pp.120-128
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• 2024

Purpose: The purpose of this study was to compare the clinical and radiographic outcomes with use of short-curved stems versus standard-length single wedged stems over a minimum follow-up period of five years. Materials and Methods: A retrospective study of primary total hip arthroplasties performed using the Fitmore^® stem (127 hips, 122 patients) and the M/L taper^® stem (195 hips, 187 patients) between October 2012 and June 2014 was conducted. The clinical and radiographic outcomes were obtained for evaluation over a minimum follow-up period of five years. Results: In both the Fitmore^® and M/L taper^® groups, the mean Harris hip score improved from 52.4 and 48.9 preoperatively to 93.3 and 94.5 at the final follow-up, respectively (P=0.980). The mean Western Ontario and McMaster Universities Osteoarthritis Index scores also improved from 73.3 and 76.8 preoperatively to 22.9 and 25.6 at the final follow-up, respectively (P=0.465). Fifteen hips (Fitmore^®: 14 hips; M/L taper^®: one hip, P<0.001) developed intraoperative cracks and were treated simultaneously with cerclage wiring. Radiography showed a radiolucent line in 24 hips in the Fitmore^® group and 12 hips in the M/L taper^® group (P=0.125). Cortical hypertrophy was detected in 29 hips (Fitmore^® group: 28 hips; M/L taper^® group: one hip, P<0.001). Conclusion: Similarly favorable clinical and radiographic outcomes were achieved with use of both short-curved stems and standard-length single wedged stems. However, higher cortical hypertrophy and a higher rate of femoral crack were observed with use of Fitmore^® stems.

• Journal of Chest Surgery
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• v.36 no.2
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• pp.63-72
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• 2003

Although a variety of synthetic vascular grafts are available in modern vascular surgery, no ideal prosthesis ha,4 yet been developed. Small-caliber vascular grafts with low flow, as used in the lower extremity, continue to become thrombosed at unacceptable rates. We have developed and evaluated the new antithrombogenic blood contacting surfaces in canine model. Material and Method: Two now antithrombogenic blood contacting surfaces(Polyvinylalcohol -Polyurethane(PVA-PU) blend and natural Graphite-polyurethane(G-PU) blend) have been developed and evaluated in canine model, using vascular grafts and patches. The luminal surfaces of the test vascular grafts(5 mm ID) were fabricated by dipping a glass rod in PVA-PU blend solution(50 % PVA) using phase separation method. Mongrel dogs of either sex weighing 18-22 kg were anesthetized by endotracheal intubation using halothane and their lungs were ventilated with a volume-cycled ventilator, Maintenance anesthesia with 0.5-1.0% halothane and supplemental oxygen was used. Two pairs were used for comparison in the bilateral femoral arteries for both vascular grafts(PVA-PU vs. PU) and vascular patches(G-PU vs. PU). Bilateral groin incisions were made and the arteries were exposed and clamped. After an excision of 1 cm of the artery between clamps, a grail of 2.5 cm in length was implanted end-to-end using 6-0 polypropylene suture. The vascular patch was implanted as a form of on-lay patch. Animals were sacrificed at 1, 2, 4, 6, 8 and 16 weeks for vascular grafts and 1, 2. 4 and 6 weeks for vascular patches. Result The vascular grafts of PVA-PU blends showed patent lumina in the 2 and 16 weeks animals, while those of PU showed a patent lumen in 2 weeks animal. PVA-PU graft of 16 weeks showed a fairly clean luminal surface. A light microscopic finding of this graft demonstrated good tissue infiltration through porosity, The animals with vascular patches showed patent arteries in both groups except 2 weeks animal. Scanning electron microscopy of the luminal surfaces of G-PU patches in 4 and 6 weeks animals showed endothelial cell covering with microvilli. PU patches showed qualitatively less endothelial cell covering. Conclusion: In conclusion, PVA-PU and G-PU blends can be a promising blood contacting surfaces for application in a synthetic vascualr graft. However, further animal study is needed to determine the real long-term effects of these methods of surface modifications.