• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
• /
• 2002.10b
• /
• pp.365-366
• /
• 2002

The sliding wear behavior of ultra high molecular weight polyethylene (UHMWPE) was examined on a novel low temperature degradation-free zirconia/alumina composite material and conventional alumina and zirconia ceramics used for femoral head in total hip joint replacement. The wear of UHMWPE pins against these ceramic disks was evaluated by performing linear reciprocal sliding and repeat pass rotational sliding tests for one million cycles in bovine serum. The weight loss of polyethylene against the novel low temperature degradation-free zirconia/alumina composite disks was much less than those against conventional ceramics for all tests. The mean weight loss of the polyethylene pins was more io the linear reciprocal sliding test than in the repeal pass rotational sliding lest for all kinds of disk materials. Neither the coherent transfer film nor the surface damage was observed on the surface of the novel zirconia/alumina composite disks during the test. The observed r,'stilts indicated that the wear of the polyethylene was closely related to contacting materials and kinematic motions. In conclusion, the novel zirconia/alumina composite leads the least wear of polyethylene among the tested ceramics and demonstrates the potential as lhe alternative materials for femoral head in total hip joint replacement.

• Journal of Korean Foot and Ankle Society
• /
• v.11 no.1
• /
• pp.111-114
• /
• 2007

Open calcaneal fracture with more than lateral half of bone loss and soft tissue defect occurred in 17 year-old male patient due to motor vehicle accident. Soft tissue defect included heel pad, peroneal tendon. Bone loss involved mainly most part of inferior tuberosity but not subtalar joint. Open dressing and debridement were done daily in operating room and antibiotics administration was started. After granulation tissue formed, femoral head allograft was performed and fixed with 6.0 mm screws to replace bone defect. Soft tissue defect was covered with latissimus dorsi musculocutaneous free flap. No sign of infection nor major osteolysis was observed in 15 months follow up period. Soft tissue defect was covered with latissimus dorsi musculocutaneous free flap.

• Journal of Veterinary Clinics
• /
• v.18 no.3
• /
• pp.243-248
• /
• 2001

Radiographic findings of degenerative joint disease (DJD) in the coxofemoral joints were studied in 108 dogs referred to Veterinary Medical Teaching Hospital, College of Veterinary Medicine, Seoul National University. Radiographic findings were identified with a extended ventrodorsal projection. Clinical signs such as pain in the affected joint, exercise intolerance, lameness, crepitation on flexion and extension of the joint and decreased range of motion, were shown in 40% and radiographic changes of bilateral coxofemoral joints were identified in 69% of a group of dogs. There are no sex predilections. Thirty-seven dogs were diagnosed as canine hip dysplasia (CHD; 10 cases), avascular necrosis of the femoral head (Legg-Calves-Perthes disease [LCPD]; 12 cases), fracture of the acetabulum (1 case), luxation(10 cases) and subluxation (15 cases), however, luxation and subluxation were identified in 11 dogs affected with CHD and LCPD. Causes of DJD in others (71case) were not identified. Radio-graphic findings identified included osteophyte formation at the attachment of the joint capsule (70%), sclerosis of the subchondral bone of the cranial acetabular edge (47%), remodeling of the femoral head (34%), thickening of the femoral neck(31%), perichondral osteophyte formation (31%), joint laxity (30%) and so on. All of the dogs diagnosed as CHD were large breed such as Retriever, Germain Shepherd, and Weimaraner and their age was under 1 year. This condition occurred bilaterally in 70% of affected animals. Dogs diagnosed as LCPD were young (under 1 year), small breed dogs. The incidence of LCPD is greater in Yorkshire Terrier, Miniature Pinscher and Poodle. This condition occurred unilaterally in 67% of affected animals. Clinical signs of dogs with unknown cause were shown in 15% and this condition occurred bilaterally in 75% of affected animals. Radiographic findings varied with patient's age and breed, however, the most common finding was osteophyte formation at the attachment of the joint capsule.

• IMMUNE NETWORK
• /
• v.22 no.3
• /
• pp.25.1-25.11
• /
• 2022

IL-34 can promote osteoclast differentiation and activation, which may contribute to steroid-induced osteonecrosis of the femoral head (ONFH). Animal model was constructed in both BALB/c and IL-34 deficient mice to detect the relative expression of inflammation cytokines. Micro-CT was utilized to reveal the internal structure. In vitro differentiated osteoclast was induced by culturing bone marrow-derived macrophages with IL-34 conditioned medium or M-CSF. The relative expression of pro-inflammation cytokines, osteoclast marker genes, and relevant pathways molecules was detected with quantitative real-time RT-PCR, ELISA, and Western blot. Up-regulated IL-34 expression could be detected in the serum of ONFH patients and femoral heads of ONFH mice. IL-34 deficient mice showed the resistance to ONFH induction with the up-regulated trabecular number, trabecular thickness, bone value fraction, and down-regulated trabecular separation. On the other hand, inflammatory cytokines, such as TNF-α, IFN-γ, IL-6, IL-12, IL-2, and IL-17A, showed diminished expression in IL-34 deficient ONFH induced mice. IL-34 alone or works in coordination with M-CSF to promote osteoclastogenesis and activate ERK, STAT3, and non-canonical NF-κB pathways. These data demonstrate that IL-34 can promote the differentiation of osteoclast through ERK, STAT3, and non-canonical NF-κB pathways to aggravate steroid-induced ONFH, and IL-34 can be considered as a treatment target.

• Journal of Biomedical Engineering Research
• /
• v.29 no.6
• /
• pp.451-456
• /
• 2008

Total knee arthroplasty(TKA) using computer-assisted navigation has been increased in order to improve the accuracy of femoral and tibial components implantation. Recently, a few clinical studies have reported on the femoral stress fracture after TKA using computer-assisted navigation. The purpose of this study is to investigate the stress concentration around the femoral pin-hole for different pin-hole diameter, the modes of pin penetration by finite element analysis to understand the effects of pin-hole parameters on femoral stress fracture risk. A three-dimensional finite element model of a male femur was reconstructed from 1 mm thick computed tomography(CT) images. The bone was rigidly fixed to a 25 mm above the distal end and 1500 N of axial compressive force and 12 Nm of axial torsion were applied at the femoral head. For all cases, transcortical pin penetration mode showed the highest stress fracture risk and unicortical pin penetration mode showed the lowest stress concentration. Pin-hole diameter increased the stress concentration, but pin number did not increase the stress dramatically. The results of this study provided a biomechanical guideline for pin-hole fracture risk of the computer navigated TKA.

• Hip & pelvis
• /
• v.34 no.1
• /
• pp.35-44
• /
• 2022

Purpose: Osteosynthesis has been recommended for treatment of Pauwels type III femoral neck fractures in young patients. However, no implant of choice has been reported so far. This study was conducted in order to compare the fixation stability of two conventional fixation methods with three different novel fixed angle devices in this type of fracture. Materials and Methods: A total of 25 composite femurs (4th Generation Saw bone; Pacific Research Laboratories, USA) corresponding to human bone were used. Pauwels type III fracture type was uniformly reproduced. Specimens were fixed with a cannulated screw, cannulated screw with cable, and Intertan nail, dynamic hip screw, and IKEY nail. Measurement of failure loads and the rotational change of the femoral head fragment was performed for evaluation of fixation stability. Results: All implants were compared with cannulated screw and dynmaic hip screw. No meaningful improvement was observed for the cannulated screw with cable compared with the cannulated screw and dynamic hip screw. Meaningful improvement in load-to-failure and y-rotation and z-rotation was observed for both the Intertan nail and IKEY nail compared with the cannulated screw. However, compared with the dynamic hip screw, only the IKEY nail showed improvement in the same profile but the Intertan nail did not. Conclusion: Among novel fixed angle devices, meaningful improvement was observed for the IKEY nail compared with conventional implants. Strengths of this implant include biomechanical stability and simplicity of surgical technique, indicating that it may be another good option for osteosynthesis of Pauwels type III femoral neck fractures.

• Journal of the Korean Orthopaedic Association
• /
• v.56 no.4
• /
• pp.305-309
• /
• 2021

Purpose: This study analyzed the increase in disposal rate of femoral heads in the bone bank of a single hospital from medical disease and drug history, as assessed by the Korean health insurance review and assessment service. Materials and Methods: The disposal rate and cause of 340 femoral heads were analyzed according to the regulations of the bone bank based on the standard model of the Ministry of food and drug safety. Results: One hundred and seven (33%) of 323 femoral heads collected from 2009 to 2018, and 65 (46%) of 142 femoral heads collected from 2015 to 2018 were discarded. The most common causes were related to the history of dementia and the administration of radioisotope for nuclear medicine. Conclusion: The current methods and screening tools can lead to errors in disposing of the available tissues in a bone bank. Thus, improved standards and screening methods are needed.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
• /
• 2004.11a
• /
• pp.355-361
• /
• 2004

Ceramic femoral heads in the total hip replacement have been developed to reduce the polyethylene liner wear, Alumina and zirconia (3Y-TZP) having the excellent tribological properties are coupled against acetabular cups of polyethylene and are used in clinical application worldwide. However, alumina has a risk of catastrophic failure, and zirconia has the low temperature degradation in spite of enhanced fracture toughness. Recently, novel zirconia/alumina composite is very attractive due to the low temperature degradation (LTD)-free character and high fracture toughness. In the present study, we focus on the wear of ceramic on ceramic, which are able to be used as femoral heads and acetabular cups. Therefore, LTD-free zirconia/alumina composites with three compositions are made in a form of disk and cylinder, and the wear of the composites is performed on pin-on-disk type wear tester. The wear is conducted with or without lubricant. All the composites fabricated with the different composition show the good wear resistance.

• Journal of the Korean Arthroscopy Society
• /
• v.2 no.1
• /
• pp.1-3
• /
• 1998

The PCL reconstruction in chronic isolate PCL reconstruction was still controversy. 1) In isolate PCL deficient knee, functionally not so bad as like ACL deficient knee. 2) The result of the PCL reconstruction was not as good as ACL reconstruction. Therefore, isolate PCL injuries has been treated as nonoperatively. Hey Grovere, who was the first to attempt an intra-articular reconstruction of the PCL, utilized the semi-tendinous tendon other static procedures have been described in only a few cases with very limited follow-up. Dynamic procedures utilizing the medial head of the gastrocnemius has been reported by Hugston and Degenhardt, Kennedy and Grainger, and Insall and Hood. These procedures did not improve static stability. Dr Clancy, who was introduce the use of BPTB for the PCL reconstruction transtibial and femoral tunnel. From 1995, untill early 1990 PCL reconstruction was done as tend as placement of the isometric point. Physiometic placement of Anatomical placement of the femoral tunnel in PCL reconstruction were introduced in 1995. Tibial Inlay Technique was reported by Dr Berg in 1995. The main advantage of the tibial Inlay Technique was to avoid fraying of the graft at the posterior tibial tunnel orifice. In complete PCL ruptured and severely posterior unstable knee, dual femoral tunnel technique will be to get better result than one bundle technique. To achieve restoration of normal posterior laxity, it is critical to address the posterior as well as the posterolateral structures. Futher research is necessary to evaluate new surgical approches such as double-bundle reconstructions and tibial inlay techniques as well as improved techniques for capsular and collateral ligament injuries.

• Journal of Veterinary Clinics
• /
• v.37 no.2
• /
• pp.67-74
• /
• 2020

The purpose of this study is to identify clinical features of sound (non-lame) dogs with medial patellar luxation (MPL). Medical records of 72 dogs diagnosed with MPL were retrospectively reviewed. There were no significances in breed, sex, body weight, body condition score (BCS), osteoarthritis (OA) score, inclination of the femoral head angle (IFA), and mechanical medial proximal tibial angle (mMPTA) between sound and lame dogs, respectively. The mean age of sound dogs was significantly higher than that of lame dogs (P < 0.05), especially in MPL grade 3. The frequency of sound dogs with MPL grade 1 and 2 was 2.3 times higher than that of sound dogs with MPL grade 3 and 4 (P < 0.05). The anatomical lateral distal femoral angle (aLDFA) of sound dogs was significantly lower than that of lame dogs (P < 0.05). However, there were no statistical differences in aLDFA between sound and lame dogs in MPL grade 1, 2, and 4, except for MPL grade 3. This study suggests that in case of MPL grade 1 and 2, frequency of sound dogs is significantly high, and also that in MPL grade 3, if mean ± (standard deviation) age of the dogs is 7.4 ± 3.6 years old and the aLDFA is 105.6 ± 4.1 degrees, they are very highly possible to be sound dogs.