1.Influence of Patellar Implant Shape on Patellofemoral Contact Pressure Using Finite Element Analysis
Hun Sik CHO ; Hyoung-Taek HONG ; Hyuck Min KWON ; Yong-Gon KOH ; Seong-Mun HWANG ; Kwan Kyu PARK ; Kyoung-Tak KANG
Yonsei Medical Journal 2025;66(6):383-389
Purpose:
This study focused on analyzing the contact pressure and area on different patellar component designs in total knee arthroplasty (TKA) to evaluate biomechanics related to the patellofemoral (PF) joint.
Materials and Methods:
The patellar components studied included the dome design, modified dome design, and anatomical design implants. Using finite element analysis and mechanical testing, the pressure and area were evaluated. The first loading condition was simulated at flexion angles of 0°, 15°, 45°, 90°, 120°, and 150°. The second loading condition was simulated for a clinically relevant scenario, involving a 2-mm medial shift at a flexion angle of 45°.
Results:
For both the modified dome and anatomical designs, the contact area and pressure increased with the flexion angle. The dome design reached its maximum contact area at a flexion angle of 120°. Among the designs, the anatomical design had the largest contact area and a lower contact pressure compared to the dome and modified dome designs. However, when a medial shift of 2 mm was simulated at a 45° flexion angle, which can occur clinically, the anatomical design showed edge contact, leading to higher contact pressure and reduced contact area. In contrast, the modified dome design demonstrated the lowest contact pressure and the greatest contact area under the same shifted conditions.
Conclusion
These findings suggest that the design of the patellar component significantly affects patellar biomechanics and stability. Specifically, the modified dome design showed improved biomechanical effects in clinically relevant scenarios. Therefore, patellar components with a modified dome design are expected to better manage PF joint pain and reduce complications in TKA.
2.Influence of Patellar Implant Shape on Patellofemoral Contact Pressure Using Finite Element Analysis
Hun Sik CHO ; Hyoung-Taek HONG ; Hyuck Min KWON ; Yong-Gon KOH ; Seong-Mun HWANG ; Kwan Kyu PARK ; Kyoung-Tak KANG
Yonsei Medical Journal 2025;66(6):383-389
Purpose:
This study focused on analyzing the contact pressure and area on different patellar component designs in total knee arthroplasty (TKA) to evaluate biomechanics related to the patellofemoral (PF) joint.
Materials and Methods:
The patellar components studied included the dome design, modified dome design, and anatomical design implants. Using finite element analysis and mechanical testing, the pressure and area were evaluated. The first loading condition was simulated at flexion angles of 0°, 15°, 45°, 90°, 120°, and 150°. The second loading condition was simulated for a clinically relevant scenario, involving a 2-mm medial shift at a flexion angle of 45°.
Results:
For both the modified dome and anatomical designs, the contact area and pressure increased with the flexion angle. The dome design reached its maximum contact area at a flexion angle of 120°. Among the designs, the anatomical design had the largest contact area and a lower contact pressure compared to the dome and modified dome designs. However, when a medial shift of 2 mm was simulated at a 45° flexion angle, which can occur clinically, the anatomical design showed edge contact, leading to higher contact pressure and reduced contact area. In contrast, the modified dome design demonstrated the lowest contact pressure and the greatest contact area under the same shifted conditions.
Conclusion
These findings suggest that the design of the patellar component significantly affects patellar biomechanics and stability. Specifically, the modified dome design showed improved biomechanical effects in clinically relevant scenarios. Therefore, patellar components with a modified dome design are expected to better manage PF joint pain and reduce complications in TKA.
3.Influence of Patellar Implant Shape on Patellofemoral Contact Pressure Using Finite Element Analysis
Hun Sik CHO ; Hyoung-Taek HONG ; Hyuck Min KWON ; Yong-Gon KOH ; Seong-Mun HWANG ; Kwan Kyu PARK ; Kyoung-Tak KANG
Yonsei Medical Journal 2025;66(6):383-389
Purpose:
This study focused on analyzing the contact pressure and area on different patellar component designs in total knee arthroplasty (TKA) to evaluate biomechanics related to the patellofemoral (PF) joint.
Materials and Methods:
The patellar components studied included the dome design, modified dome design, and anatomical design implants. Using finite element analysis and mechanical testing, the pressure and area were evaluated. The first loading condition was simulated at flexion angles of 0°, 15°, 45°, 90°, 120°, and 150°. The second loading condition was simulated for a clinically relevant scenario, involving a 2-mm medial shift at a flexion angle of 45°.
Results:
For both the modified dome and anatomical designs, the contact area and pressure increased with the flexion angle. The dome design reached its maximum contact area at a flexion angle of 120°. Among the designs, the anatomical design had the largest contact area and a lower contact pressure compared to the dome and modified dome designs. However, when a medial shift of 2 mm was simulated at a 45° flexion angle, which can occur clinically, the anatomical design showed edge contact, leading to higher contact pressure and reduced contact area. In contrast, the modified dome design demonstrated the lowest contact pressure and the greatest contact area under the same shifted conditions.
Conclusion
These findings suggest that the design of the patellar component significantly affects patellar biomechanics and stability. Specifically, the modified dome design showed improved biomechanical effects in clinically relevant scenarios. Therefore, patellar components with a modified dome design are expected to better manage PF joint pain and reduce complications in TKA.
4.Influence of Patellar Implant Shape on Patellofemoral Contact Pressure Using Finite Element Analysis
Hun Sik CHO ; Hyoung-Taek HONG ; Hyuck Min KWON ; Yong-Gon KOH ; Seong-Mun HWANG ; Kwan Kyu PARK ; Kyoung-Tak KANG
Yonsei Medical Journal 2025;66(6):383-389
Purpose:
This study focused on analyzing the contact pressure and area on different patellar component designs in total knee arthroplasty (TKA) to evaluate biomechanics related to the patellofemoral (PF) joint.
Materials and Methods:
The patellar components studied included the dome design, modified dome design, and anatomical design implants. Using finite element analysis and mechanical testing, the pressure and area were evaluated. The first loading condition was simulated at flexion angles of 0°, 15°, 45°, 90°, 120°, and 150°. The second loading condition was simulated for a clinically relevant scenario, involving a 2-mm medial shift at a flexion angle of 45°.
Results:
For both the modified dome and anatomical designs, the contact area and pressure increased with the flexion angle. The dome design reached its maximum contact area at a flexion angle of 120°. Among the designs, the anatomical design had the largest contact area and a lower contact pressure compared to the dome and modified dome designs. However, when a medial shift of 2 mm was simulated at a 45° flexion angle, which can occur clinically, the anatomical design showed edge contact, leading to higher contact pressure and reduced contact area. In contrast, the modified dome design demonstrated the lowest contact pressure and the greatest contact area under the same shifted conditions.
Conclusion
These findings suggest that the design of the patellar component significantly affects patellar biomechanics and stability. Specifically, the modified dome design showed improved biomechanical effects in clinically relevant scenarios. Therefore, patellar components with a modified dome design are expected to better manage PF joint pain and reduce complications in TKA.
5.Influence of Patellar Implant Shape on Patellofemoral Contact Pressure Using Finite Element Analysis
Hun Sik CHO ; Hyoung-Taek HONG ; Hyuck Min KWON ; Yong-Gon KOH ; Seong-Mun HWANG ; Kwan Kyu PARK ; Kyoung-Tak KANG
Yonsei Medical Journal 2025;66(6):383-389
Purpose:
This study focused on analyzing the contact pressure and area on different patellar component designs in total knee arthroplasty (TKA) to evaluate biomechanics related to the patellofemoral (PF) joint.
Materials and Methods:
The patellar components studied included the dome design, modified dome design, and anatomical design implants. Using finite element analysis and mechanical testing, the pressure and area were evaluated. The first loading condition was simulated at flexion angles of 0°, 15°, 45°, 90°, 120°, and 150°. The second loading condition was simulated for a clinically relevant scenario, involving a 2-mm medial shift at a flexion angle of 45°.
Results:
For both the modified dome and anatomical designs, the contact area and pressure increased with the flexion angle. The dome design reached its maximum contact area at a flexion angle of 120°. Among the designs, the anatomical design had the largest contact area and a lower contact pressure compared to the dome and modified dome designs. However, when a medial shift of 2 mm was simulated at a 45° flexion angle, which can occur clinically, the anatomical design showed edge contact, leading to higher contact pressure and reduced contact area. In contrast, the modified dome design demonstrated the lowest contact pressure and the greatest contact area under the same shifted conditions.
Conclusion
These findings suggest that the design of the patellar component significantly affects patellar biomechanics and stability. Specifically, the modified dome design showed improved biomechanical effects in clinically relevant scenarios. Therefore, patellar components with a modified dome design are expected to better manage PF joint pain and reduce complications in TKA.
6.A Novel Robot-Assisted Kinematic Measure for Children with Attention-Deficit/Hyperactivity Disorder: A Preliminary Study
Aran MIN ; Johanna Inhyang KIM ; Hak Jong NOH ; Moon Sang KIM ; Hyo-Shin LEE ; Mun-Taek CHOI ; Kyuha LEE ; Jun-Ho SEO ; Ga Hyun LEE ; Seong-kyu KANG ; Dong Hyun AHN
Psychiatry Investigation 2021;18(7):645-651
Objective:
Attention-deficit/hyperactivity disorder (ADHD) is a neurodevelopmental disorder characterized by inattention, hyperactivity, and impulsivity. In contrast to neurocognitive measurements of inattention and impulsivity, there has been limited research regarding the objective measurement of hyperactivity in youths with ADHD. The purpose of the present study was to investigate the clinical effectiveness of a newly developed Robot-assisted Kinematic Measure for ADHD (RAKMA) in children with ADHD.
Methods:
In total, 35 children with ADHD aged 5 to 12 years and 50 healthy controls (HCs) were recruited, and the parents completed the Child Behavior Checklist and the Korean ADHD Diagnostic Scale. RAKMA performance was represented by RAKMA stimulus–response and hyperactivity variables. We compared the RAKMA performance of those with ADHD and with that of HCs and also investigated the correlation between the RAKMA variables and ADHD clinical scale scores.
Results:
Significant differences between the ADHD and HC groups were observed regarding most RAKMA variables, including correct reactions, commission errors, omission errors, reaction times, migration distance, and migration speed scores. Significant correlations were detected between various ADHD clinical scale scores and RAKMA variables.
Conclusion
The RAKMA was a clinically useful tool for objectively measuring hyperactivity symptoms in children with ADHD. Further studies with larger samples are warranted.
7.A Novel Robot-Assisted Kinematic Measure for Children with Attention-Deficit/Hyperactivity Disorder: A Preliminary Study
Aran MIN ; Johanna Inhyang KIM ; Hak Jong NOH ; Moon Sang KIM ; Hyo-Shin LEE ; Mun-Taek CHOI ; Kyuha LEE ; Jun-Ho SEO ; Ga Hyun LEE ; Seong-kyu KANG ; Dong Hyun AHN
Psychiatry Investigation 2021;18(7):645-651
Objective:
Attention-deficit/hyperactivity disorder (ADHD) is a neurodevelopmental disorder characterized by inattention, hyperactivity, and impulsivity. In contrast to neurocognitive measurements of inattention and impulsivity, there has been limited research regarding the objective measurement of hyperactivity in youths with ADHD. The purpose of the present study was to investigate the clinical effectiveness of a newly developed Robot-assisted Kinematic Measure for ADHD (RAKMA) in children with ADHD.
Methods:
In total, 35 children with ADHD aged 5 to 12 years and 50 healthy controls (HCs) were recruited, and the parents completed the Child Behavior Checklist and the Korean ADHD Diagnostic Scale. RAKMA performance was represented by RAKMA stimulus–response and hyperactivity variables. We compared the RAKMA performance of those with ADHD and with that of HCs and also investigated the correlation between the RAKMA variables and ADHD clinical scale scores.
Results:
Significant differences between the ADHD and HC groups were observed regarding most RAKMA variables, including correct reactions, commission errors, omission errors, reaction times, migration distance, and migration speed scores. Significant correlations were detected between various ADHD clinical scale scores and RAKMA variables.
Conclusion
The RAKMA was a clinically useful tool for objectively measuring hyperactivity symptoms in children with ADHD. Further studies with larger samples are warranted.
8.Ruptured Tubal Pregnancy with Massive Retroperitoneal Hemorrhage.
Soonchunhyang Medical Science 2017;23(1):61-64
Ectopic pregnancy is an implantation of the fertilized ovum on a place except the endometrium. Most of the ectopic pregnancies are located at the fallopian tube. Few cases of retroperitoneal hematoma associated with ectopic pregnancy have been reported on previously; in each the retroperitoneal space had been the site of implantation. In contrast, we treated a patient with an ectopic pregnancy that implanted in the tube and then perforated through into the retroperitoneal space. To our knowledge this is very rare case of retroperitoneal hematoma caused by a ruptured tubal pregnancy.
Endometrium
;
Fallopian Tubes
;
Female
;
Hematoma
;
Hemorrhage*
;
Humans
;
Laparoscopy
;
Pregnancy
;
Pregnancy, Ectopic
;
Pregnancy, Tubal*
;
Retroperitoneal Space
;
Zygote
9.Complete tubular duplication of colon in an adult: a rare cause of colovaginal fistula.
Hae Il JUNG ; Hyoung Uk LEE ; Tae Sung AHN ; Jong Eun LEE ; Hyun Yong LEE ; Seong Taek MUN ; Moo Jun BAEK ; Sang Ho BAE
Annals of Surgical Treatment and Research 2016;91(4):207-211
Alimentary tract duplications are uncommon congenital anomalies that usually present during the first decade of life. Complete duplication of the colon in adults is very rare and difficult to diagnose preoperatively. We report a case of a 40-year-old female with complete tubular duplication which was initially misdiagnosed as a salpingeal abscess due to colovaginal fistula.
Abscess
;
Adult*
;
Colon*
;
Female
;
Fistula*
;
Humans
10.A comparison of oxycodone and fentanyl in intravenous patient-controlled analgesia after laparoscopic hysterectomy.
Nan Seol KIM ; Kyu Sik KANG ; Sie Hyeon YOO ; Jin Hun CHUNG ; Ji Won CHUNG ; Yonghan SEO ; Ho Soon CHUNG ; Hye Rim JEON ; Hyung Youn GONG ; Hyun Young LEE ; Seong Taek MUN
Korean Journal of Anesthesiology 2015;68(3):261-266
BACKGROUND: We planned to compare the effect of intravenous oxycodone and fentanyl on post-operative pain after laparoscopic hysterectomy. METHODS: We examined 60 patients were randomized to postoperative pain treatment with either oxycodone (n = 30, Group O) or fentanyl (n = 30, Group F). The patients received 10 mg oxycodone/100 microg fentanyl with ketorolac 30 mg before the end of anesthesia and then continued with patient-controlled analgesia for 48 h postoperatively. RESULTS: The accumulated oxycodone consumption was less than fentanyl during 8, 24 and 48 h postoperatively. Numeric rating score of Group O showed significantly lower than that of Group F during 30 min, 2, 4, 8 and 24 h postoperatively. The incidences of adverse reactions were similar in the two groups, though the incidence of nausea was higher in the Group O during the 24 and 48 h postoperative period. CONCLUSIONS: Oxycodone IV-PCA was more advantageous than fentanyl IV-PCA for laparoscopic hysterectomy in view of accumulated oxycodone consumption, pain control and cost beneficial effect. However, patient satisfaction was not good in the group O compared to group F.
Analgesia, Patient-Controlled*
;
Anesthesia
;
Fentanyl*
;
Humans
;
Hysterectomy*
;
Incidence
;
Ketorolac
;
Nausea
;
Oxycodone*
;
Pain, Postoperative
;
Patient Satisfaction
;
Postoperative Period

Result Analysis
Print
Save
E-mail