• Journal of Korean Neurosurgical Society
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• v.65 no.6
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• pp.779-789
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• 2022

Objective : To analyze the effects of the number and shape of fenestrations on the mechanical strength of pedicle screws and the effects of bone cement augmentation (BCA) on the pull-out strength (POS) of screws used in conventional BCA. Methods : For the control group, a conventional screw was defined as C1, a screw with cannulated end-holes was defined as C2, a C2 screw with six pinholes was defined as C3, and the control group type was set. Among the experimental screws, T1 was designed using symmetrically placed thru-hole type fenestrations with an elliptical shape, while T2 was designed with half-moon (HM)-shaped asymmetrical fenestrations. T3 and T4 were designed with single HM-shaped fenestrations covering three pitches and five pitches, respectively. T5 and T6 were designed with 0.6-mm and 1-mm wider fenestrations than T3. BCA was performed by injecting 3 mL of commercial bone cement in the screw, and mechanical strength and POS tests were performed according to ASTM F1717 and ASTM F543 standards. Synthetic bone (model #1522-505) made of polyurethane foam was used as a model of osteoporotic bone, and radiographic examinations were performed using computed tomography and fluoroscopy. Results : In the fatigue test, at 75% ultimate load, fractures occurred 7781 and 9189 times; at 50%, they occurred 36122 and 82067 times; and at 25%, no fractures occurred. The mean ultimate load for each screw type was 219.1±52.39 N for T1, 234.74±15.9 N for T2, 220.70±59.23 N for T3, 216.45±32.4 N for T4, 181.55±54.78 N for T5, and 216.47±29.25 N for T6. In comparison with C1, T1, T2, T3, T4, and T6 showed significantly different ultimate load values (p<0.05). However, when the values for C2 and the fenestrated screws were evaluated with an unpaired t test, the ultimate load value of C2 significantly differed only from that of T2 (p=0.025). The ultimate load value of C3 differed significantly from those of T1 and T2 (C3 vs. T1 : p=0.048; C3 vs. T2 : p<0.001). Linear correlation analysis revealed a significant correlation between the fenestration area and the volume of bone cement (Pearson's correlation coefficient r=0.288, p=0.036). The bone cement volume and ultimate load significantly correlated with each other in linear correlation analysis (r=0.403, p=0.003). Conclusion : Fenestration yielded a superior ultimate load in comparison with standard BCA using a conventional screw. In T2 screws with asymmetrical two-way fenestrations showed the maximal increase in ultimate load. The fenestrated screws can be expected to show a stable position for the formation of the cement mass.

• Journal of the Korean Arthroscopy Society
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• v.2 no.2
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• pp.173-176
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• 1998

Isolated posterior cruciate ligament injuries are rare and their management is controversial. But, there is general concept that a bony avulsion of posterior cruciate ligament should be repaired. The treatments for the bony avulsion of posterior cruciate ligament were conservative treatment, open reduction and internal fixation and arthroscopic fixation. We report 2 cases of posterior cruciate ligament avulsion fractures, which were arthroscopically reduced and stabilized with cannulated screws and Kirschner wires, and introduce the arthroscopic fixation technique.

• Clinics in Shoulder and Elbow
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• v.22 no.2
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• pp.106-109
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• 2019

Acromial fractures are well-documented complications subsequent to reverse shoulder arthroplasty (RSA), and most appear as stress fractures with no history of single trauma. To date, no study has reported the occurrence of acute displaced acromial fracture due to sudden strong deltoid contraction during heavy work. Displacement of the fracture results in a challenging surgery since it is difficult to obtain adequate fixation in thin and osteoporotic bones. We report a rare case of acute displaced acromial fracture after successful RSA treatment, using a novel technique of open reduction and internal fixation, applying two 4.5 mm cannulated screws and lateral clavicle precontoured plate.

• Journal of Korean Orthopaedic Sports Medicine
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• v.4 no.2
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• pp.116-121
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• 2005

Purpose: Isolated capitellar fractures are rare, intra-articular fractures requiring an aggressive management regimen. Review the outcome after open reduction and internal fixation of the capitellar fractures. Materials and Methods: From 1998 to 2004, 4 patients with displaced fractures of the humeral capitellum were treated by open reduction and internal fixation of the capitellar fragments with cannulated screws. By use of the criteria of Bryan and Morrey et al, there were 3 type I fractures, 1 type III fracture. A lateral approach was used. The elbows were immobilized postoperatively for 4 to 28 days We evaluated the range of motion, stability, and pain using the criteria of Mayo score. Results: The follow-up period ranged from 12 to 36 months (mean, 15months). Three patients had a stable, pain-free elbow with good range of motion at follow-up. One patient with a neglected capitellar fracture have felxtion cpontracture of 40 degrees with 100 degrees of further felxion(total arc: 60) due to poor compliance to the postoperative rehabilitation. All fractures healed, and there was no evidence of avascular necrosis or degenerative change. Conclusion: Capitellar fractures, rare in case, gave a good result after open reduction and simple internal fixation with cannulated screws without any problem.

• Journal of Korean Foot and Ankle Society
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• v.18 no.4
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• pp.189-194
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• 2014

Purpose: The purpose of this study was to compare the clinical and radiologic results of arthrodesis between anterior approach and transfibular approach arthrodesis in ankle arthritis. Materials and Methods: There were 61 cases of ankle arthritis treated by anterior or transfibular ankle arthrodesis in our hospital from April 2008 to March 2012. We investigated 29 cases (27 patients) who underwent ankle arthrodesis with an anterior approach (15 cases) and transfibular approach (14 cases), and were followed for over two years. Clinically, American Orthopaedic Foot and Ankle Society (AOFAS) ankle-hindfoot score, pain visual analogue scale (VAS), and subjective satisfaction degrees were evaluated. In addition, ankle coronal and sagittal alignments were evaluated using plain radiographs at 6 and 24 months, postoperatively. Results: Clinically, preoperative mean AOFAS score and VAS was 41.3 and 6.4, and were changed to 58.9 and 3.3 postoperatively in the anterior approach group. In the transfibular approach group, preoperative mean AOFAS score was 36.6 and VAS was 7.1, and they were changed to 54.9 and 3.4 postoperatively. However, no significant differences in the clinical results were observed between the two groups (p=0.297). Duration of attaining union was 8.1 weeks in the anterior approach group and 10.4 weeks in the transfibular approach group. Complications were delayed union in one case, nonunion in three cases, cancellous screw breakage in three cases, and complex regional reflex syndrome in one case. Conclusion: After transfibular ankle arthrodesis as treatment of ankle osteoarthritis, the tendency for valgus angulation of the ankle at the final follow-up was observed and 6.5 mm cancellous screw breakage occurred frequently. Therefore, in order to achieve better stability, it is necessary to use 6.5 mm cannulated screws rather than 6.5 mm cancellous screws for ankle arthrodesis.

• Journal of the Korean Orthopaedic Association
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• v.56 no.6
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• pp.540-545
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• 2021

A transverse fracture is the most common type of displaced patella fracture requiring surgery. These fractures are commonly fixed with parallel Kirschner wires or screws that cross the fracture line, often with an additional tension band. Nevertheless, conventional fixation methods of patella fractures have prevalent complications caused by the protrusion of wires or pins. These complications necessitate additional surgery for hardware removal, increase medical cost, and can limit the function of the knee joint. This paper reports cases treated with a minimally invasive load-sharing percutaneous suture of the patella tendon. The procedure provides reliable fixation for transverse patella fractures, minimizes soft tissue injuries, preserves blood flow, and reduces postoperative pain. In addition, the procedure also reduces the irritation and pain caused by the internal fixture, thereby reducing the risk of restricted knee joint movement.

• Clinics in Shoulder and Elbow
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• v.11 no.1
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• pp.62-65
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• 2008

Isolated acromial fracture is not common and it frequently accompanies fractures to the coracoid process and glenoid bone and also injuries to the acromioclavicular joint. Furthermore, most of these combined acromial fractures have minimal displacement, which needs no additional treatment other than protection for a certain period of time. We have experienced a case of isolated fracture of the posterolateral angle of the acromion, which we reduced and fixated using K-wire and cannulated screws. We report on the technical aspects and clinical results of this reduction and fixation, along with a review of the literature.

• Journal of Korean Foot and Ankle Society
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• v.13 no.1
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• pp.68-74
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• 2009

Purpose: This study was designed to evaluate the results and efficacy of subtalar distraction two bone-block arthrodesis for calcaneal malunion. Materials and Methods: From January 2004 to June 2007, we operated on 8 patients (12 cases). There were 7 male patients and 1 female patient; their mean age was 42 years. 8 cases among them were operated initially. The period between initial injury and arthrodesis was 21 months. At an average follow up was 19 months. In operation, we used extensile lateral approach and arthrodesis was performed through tricortical two bone-block and cannulated screws. The Ankle-Hindfoot scale was used for clinical evaluation. In radiologic analysis, plain X-ray and CT were examined union and various parameters. Results: All cases achieved radiologic union at the final follow-up. The mean Ankle-hindfoot scale (maximum of 94 points) increased from 43.4 points preoperatively to 84 points at the final follow-up. The radiologic analysis of the pre- and postoperative standing lateral radiographs showed and average increase of 5.5 mm in talo-calcaneal height, $5.1^{\circ}$ in talocalcaneal angle, $6.1^{\circ}$ in talar declination angle and decrease of $5.7^{\circ}$ in talo-first metatarsal angle. Conclusion: The short term results of subtalar distraction two bone-block arthrodesis is promising, but longer follow-up was needed.

• Journal of Korean Foot and Ankle Society
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• v.6 no.2
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• pp.201-207
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• 2002

Purpose: To present the clinical analysis of the results obtained in 38 cases of displaced intraarticular calcaneal fractures undergone combined percutaneous axial pin fixation of calcaneal body and minimal internal fixation using extensile lateral approach. Materials and Methods: From March 2000 to February 2002, thirty-eight displaced intraarticular fractures of the calcaneus in 35 patients were fixed with 3.5mm cannulated screws and percutaneous 2.5mm K-wires. The extensile lateral approach was used in all cases. The average follow-up period was 16 months. Clinical evaluation was assessed according to the Ankle-Hind Foot Scale of American Orthopedic Foot and Ankle Society. Results: The clinical results were graded as excellent in 8 cases(21%), good in 22 cases(58%), fair in 6 cases(16%), and poor in 2 cases(5%). Two cases of poor result were type IV of Sanders classification. The postoperative reduction status of the articular surface was analyzed by computed tomography in all cases and was found to be less 2mm of step off in 30 cases and between 2 and 4mm in 8 cases. Unsatisfactory results were correlated with severity of articular comminution and failure to obtain accurate reduction of the articular surface. Using early functional postoperative care, all fractures healed without secondary displacement except 1 case on an average of ten weeks. Two cases had superficial necrosis of the wound margins, however, secondary wound healing was uneventful and skin grafting was not needed. Conclusion: Combined minimal internal fixation and percutaneous pin fixation using extensile lateral approach is useful operative method of intraarticular calcaneal fractures because providing enough stability to permit functional aftercare and allowing excellent anatomical reduction. In addition, this method diminishes the risk of lateral soft tissue problems.

• Journal of Korean Foot and Ankle Society
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• v.16 no.2
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• pp.116-122
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• 2012

Purpose: Subtalar arthrodesis has been the gold standard for the painful subtalar joint disorders. Successful subtalar arthrodesis requires fusion of the 3 facet joints. The purpose of the study is to compare the clinical outcome of the posterior fixation (P2) and anterior-posterior (A1P1) fixation technique for subtalar arthrodesis which enhance anterior and middle facet fixation. Materials and Methods: The study is based on the 20 feet (19 patients) of the subtalar arthrodesis utilizing cannulated screws from September 2006 to September 2009 with at least 1-year follow-up. Two fixation techniques were utilized for the subtalar arthrodesis: 1) posterior fixation only (P2, 7 feet, 35%) and 2) anterior-posterior (A1P1) fixation method (13 feet, 65%). Visual Analog Scale Pain (VAS) score, American Orthopaedic Foot and Ankle Society (AOFAS) ankle-hindfoot score (maximum: 94 points), the time for returning to daily living and the patient satisfaction were also evaluated. Results: Average follow-up period were 13.2 months (12-3 mo). The AOFAS score improved from preoperative average 45 (0-68) to 81.6 (62-94), while VAS score was decreased from average 8.0 (3-10) to 1.8 (0-5) at final follow-up. Ninety-five percent of the patients were satisfied with surgery. All the patients returned to daily living at average 7.2 months (2-15 mo) post-surgery. Radiographically, 2 techniques both showed 100% fusion of the posterior compartment of the subtalar joint. Postoperative complications were 1 case of low grade infection and 1 case of sural nerve neuralgia. Conclusion: The subtalar arthrodesis using A1P1 fixation technique showed better fusion rate of the anterior compartment of the subtalar joint compared to P2 fixation technique although the 2 techniques both showed similar favorable clinical outcome. Therefore the A1P1 fixation technique is found to be a viable option to address chronic painful subtalar joint disorders to enhance the anterior compartment fixation.