• International Journal of Ocean System Engineering
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• v.1 no.1
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• pp.9-15
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• 2011

This study examined the relationship between the scarf angle and stress distribution, and estimated the strength recovery via a finite element analysis. The following conclusions were drawn from this study. Resin will fracture due to a tensile load with a high scarf angle, which is similar to the patch repair method. An applied stress can be loaded to a repaired laminate if the scarf angle is $5^{\circ}$. The Von-Mises stress increases with decreasing scarf angle, with the exception of a scarf angle of $30^{\circ}$, where the scarf angle can indicate the rates of shear and normal stresses. Strength recovery can be better if the scarf angle is decreased to a lower angle. However, scarf machining requires more time, a high skill level and considerable expense. Therefore, a scarf angle of $5^{\circ}$ is the most effective for a repair. These results may provide a guide for engineers wishing to formulate a standard for repair. The scarf angle needs to be carefully managed for a more efficient composite repair.

• Journal of Korean Foot and Ankle Society
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• v.16 no.2
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• pp.123-127
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• 2012

Purpose: The purpose of this study was to evaluate the clinical and radiographic results of the parallel-shaped modified Scarf osteotomy which is performed the Scarf osteotomy parallel to the shaft of the 1st metatarsal bone for hallux valgus deformities. Materials and Methods: We retrospectively reviewed 43 patients who had been treated by the parallel-shaped modified Scarf osteotomy for hallux valgus deformities between January 2006 and March 2011. We evaluated the results after this Scarf osteotomy with respect American Orthopaedic Foot & Ankle Society (AOFAS) scores, radiologic results by comparing intermetatarsal angle between 1stand 2nd metatarsal bones and hallux valgus angle. Results: We checked out the pre-operational and post-operational radiologic evaluation of intermetatarsal angle and hallux valgus angle between 1st and 2nd metatarsal bones. The mean AOFAS scores improved from 63.5 to 88.5. At final follow up, The hallux valgus angle improved from $31.4^{\circ}$ (16-52) to $9.0^{\circ}$ (3-13) and the intermetatarsal angle improved from $18.6^{\circ}$ (12-30) to $9.3^{\circ}$ (6-12) postoperatively. There was no case of major complications included recurrence of valgus deformity, correction or fixation failure and stress fractures. Conclusion: Our results suggest the our parallel-shaped modified Scarf osteotomy produces improved AOFAS scores, and effective correction of hallux valgus deformities. Our Scarf technique of osteotomy which is performed in parallel to the metatarsal bone minimizes the need for skill while more reliable and obtaining good correction and avoids associated complications.

• Clinics in Orthopedic Surgery
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• v.10 no.4
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• pp.479-483
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• 2018

Background: We developed a modified proximal scarf osteotomy technique for moderate to severe hallux valgus in an attempt to obtain better correction of the deformity. In addition, we compared the clinical and radiographic results of this modified technique with those of the classic scarf osteotomy reported in other studies. Methods: Between December 2004 and July 2009, 44 cases of modified proximal scarf osteotomy was performed in 35 patients with moderate hallux valgus. The American Orthopedic Foot and Ankle Society (AOFAS) score, visual analogue scale (VAS) score, range of motion of the first metatarsophalangeal joint, and radiographic results were evaluated. Results: The mean hallux valgus angle and the mean first intermetatarsal angle improved from an average of $32.2^{\circ}$ and $14.3^{\circ}$, respectively, to an average of $12.5^{\circ}$ and $8.6^{\circ}$, respectively. The distal metatarsal articular angle improved from an average of $18.7^{\circ}$ to $12.4^{\circ}$. The preoperative mean AOFAS and VAS scores were 47 points and 7 points, respectively, which improved to 86 points and 1 point, respectively, at the final follow-up. Limited range of motion occurred in two cases postoperatively. The height of the first metatarsal-cuneiform joint, which was an average of 15.9 mm preoperatively, did not change. The first metatarsal-talus angle increased from an average of $4.1^{\circ}$ to $7.1^{\circ}$. Conclusions: The modified proximal scarf osteotomy for the treatment of moderate hallux valgus showed similar results with the classic scarf osteotomy with regard to changes in the first intermetatarsal angle and postoperative satisfaction. Therefore, we suggest the modified proximal scarf osteotomy be considered as well as other proximal osteotomy in the treatment of moderate to severe hallux valgus.

• Journal of Korean Foot and Ankle Society
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• v.21 no.3
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• pp.93-97
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• 2017

Purpose: The aim of this study was to evaluate the radiological and clinical outcomes of scarf osteotomy for hallux valgus (HV) deformity in elderly patient with osteoporosis. Materials and Methods: A total of 58 elderly patients (mean age, 72.6 years) underwent scarf osteotomy for HV deformity between 2008 and 2015. The mean follow-up period was 24.4 months. Of the 58 patients, 42 were diagnosed with osteoporosis and 16 were diagnosed as normal. The radiological and clinical outcomes were assessed preoperatively, postoperatively, and at final follow-up, including HV angle, intermetatarsal (IM) angle, American Orthopaedic Foot and Ankle Society (AOFAS) score, patient satisfaction, visual analogue scale (VAS), and complication. Results: There was no significant difference in HV angle and IM angle between the osteoporosis group and normal bone mineral densitometry group at all time points, preoperative, postoperative, and final follow-up. Moreover, there was no statistically significant difference between the two groups with respect to the AOFAS score and VAS evaluations. In the osteoporosis group, the mean HV angle improved from $36.7^{\circ}$ preoperatively to $11.3^{\circ}$ at the time of final follow-up, and the mean IM angle improved from $13.2^{\circ}$ to $5.7^{\circ}$. The mean AOFAS score improved from 52.6 preoperatively to 89.1 at the time of final follow-up. With respect to satisfaction, 83.4% of patients were very satisfied or satisfied. There were no serious complications, and all cases showed complete union at the osteotomy site. Conclusion: We believed that scarf osteotomy is a safe, effective procedure for the correction of elderly patients with osteoporosis.

• Advances in aircraft and spacecraft science
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• v.5 no.3
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• pp.401-410
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• 2018

The aim of this work is to optimize the geometrical parameters as the adhesive thickness and the beveled angle to reduce the edge effect of the scarf and V bounded joint. A finite element analysis is done to define the generated stresses in the bounded joint. The geometrical optimum is obtained using the Experimental Design Method. Results show that the double scarf (V) joint is better than the simple scarf bounded joint.

• Journal of Korean Foot and Ankle Society
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• v.7 no.2
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• pp.157-165
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• 2003

Purpose: The purpose of this study was to the evaluate the clinical and radiographic results and complication of the Scarf osteotomy which is one of the surgical treatment of Hallux valgus. Material and Method: Fifty feet (30 patients) of moderate to severe hallux valgus deformity were operated by Scarf osteotomy procedure from January 2002 to July 2002. Patients were asked about their satisfaction in terms of pain, appearance and motion. The AOFAS clinical ratio scales and radiographic results for hallux valgus were evaluated. Result: The mean Hallux valgus angle improved from an average of 30.6 degrees to 9.0 degrees and the first intermetatarsal angle improved from an average 13.3 degrees to 5.2 degrees respectively. The preoperative mean AOFAS score was 58 points and on last follow up AOFAS score improved to 88 points. Complication which including troughing, nonunion, malunion was not developed. Conclusion: We found that Scarf osteotomy is a reliable operation for mild to moderate Hallux valgus deformity as regards firm fixation and early postoperative ambulation and large contact area for union.

• International Journal of Automotive Technology
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• v.6 no.3
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• pp.293-303
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• 2005

Bonded dissimilar materials are being increasingly used in automobiles, aircraft, rolling stocks, electronic devices and engineering structures. Bonded dissimilar materials have several material advantages over homogeneous materials such as high strength, high reliability, light weight and vibration reduction. Due to their increased use it is necessary to understand how these materials behave under stress conditions. One important area is the analysis of the stress intensity factors for interface cracks emanating from circular holes in bonded dissimilar materials. In this study, the bonded scarf joint is selected for analysis using a model which has comprehensive mixed-mode components. The stress intensity factors were determined by using the boundary element method (BEM) on the interface cracks. Variations of scarf angles and crack lengths emanating from a centered circular hole and an edged semicircular hole in the Al/Epoxy bonded scarf joints of dissimilar materials are computed. From these results, the stress intensity factor calculations are verified. In addition, the relationship between scarf angle variation and the effect by crack length and holes are discussed.

• Journal of Korean Foot and Ankle Society
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• v.17 no.4
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• pp.272-276
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• 2013

Purpose: Recurrence is one of the most common complications after primary correction for hallux valgus deformities. The purpose of this study was to evaluate the usefulness of Scarf osteotomy with axial decompression in the treatment of recurrent hallux valgus. Materials and Methods: From April 2006 to April 2011, 14 cases (12 patients) of recurrent hallux valgus were managed with shortening Scarf osteotomy. Preoperative and postoperative radiographs were reviewed for the measurement of the hallux valgus angle (HVA), intermetatarsal angle (IMA), and the amount of the $1^{st}$ metatarsal shortening. Clinical outcomes including the visual analogue scale (VAS), the AOFAS score, and the range of motion [ROM] of the 1st metatarsophalangeal (MTP) joint were evaluated. Results: The mean HVA decreased from 27.9 degrees to 5.2 and the mean IMA decreased from 12.9 to 3.4. The mean VAS improved from 5.3 to 0.3 and the mean AOFAS score improved from 41 to 90. The mean amount of the 1st metatarsal shortening was 3.4 mm (2-5). The mean ROM of the $1^{st}$ MTP joint improved from 22 degrees (15-35) to 68 (55-75). Conclusion: Scarf osteotomy associated with axial decompression can be a useful revision procedure for the treatment of recurrent hallux valgus deformity.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.20 no.7
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• pp.2087-2096
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• 1996

Recentrly advantages in composite and light weight material techniques have led to the increased use of bonded dissimilar materials such as ceramics/metal bonded joints, IC package, brazing, coating and soldering in the various industries. It is required to analyze the evaluation method of fracture strength and design methodology of bonded joints in dissimilar materials. Stress singularity according to changes of scarf angles for bonded scarf joints in dissimilar materials was investigated by the boundary element method and static experiments. In this paper, effect of the stress singularity factors at the interface edges of scarf joints on various dissmilar materials combinations were investigated by analysis of its stress and stress singularity index using 2-dimensional elastic program of boundary element method. And the variations of stress singularity index by changes for Young's modulus ratios of materials and scarf angles were investigated. Also, it is found that stress singularities at bonded interface edges are disappeared for certain combination of scarf angle in a pair of bonded dissimilar materials. As the results, it is proposed that the strength evaluation by using stress singularity factors, $\Gamma$, considering stress singularity at the interface edges of bonded dissimilar materials, is very useful.

• Journal of Korean Foot and Ankle Society
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• v.11 no.1
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• pp.23-27
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• 2007

Purpose: Scarf osteotomy can provide the simultaneous correction of the hallux valgus angle (HVA), 1-2 intermetatarsal angle ($IMA_{1-2}$), DMAA and the plantar displacement of the fragment. The study was conducted to understand the multi-dimensional correction of the hallux valgus. Materials and Methods: Fourty eight patients who had undergone Scarf osteotomy with hallux valgus at more than $30^{\circ}$ of HVA and more than $15^{\circ}$ of $IMA_{1-2}$ were studied. Before an osteotomy, a reference K-wire was inserted to the 1st metatarsal head. After the osteotomy, the plantar fragment was moved laterally and the proximal end of the fragment was forced beyond the distal end which resulted in an internal rotation of the head fragment to correct the DMAA. Results: The HVA improved an average of $33.3^{\circ}$ to $7.7^{\circ}$ with the IMA1-2 respectively from $15.4^{\circ}$ to $6.5^{\circ}$. The DMAA improved an average of $19.5^{\circ}$ ($5.2-30.9^{\circ}$) to $4.5^{\circ}$ ($0.4-13.8^{\circ}$). By checking the angle, which was at an average of $25^{\circ}$ between the plantar surface of the foot and the osteotomy plane, the average distance of 1.9 mm (1.18-3.1 mm) of plantar displacement was measured using the value of sine (sin 25 = 0.422). Conclusions: It is possible to correct the HVA, IMA1-2 and DMAA simultaneously with one osteotomy making the lateral shift, the internal rotation and the plantar displacement of the plantar head fragment as desired. Despite the technicality and difficulty of the Scarf osteotomy, once familiarized through myriad procedures, all disadvantages are outweighed by the success and satisfaction of both patient and surgeon.