Jeong Joon Yoo

Seoul National University, Sŏul, Seoul, South Korea

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Publications (71)162.07 Total impact

  • Soong Joon Lee · Hong Suk Kwak · Jeong Joon Yoo · Hee Joong Kim ·
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    ABSTRACT: We evaluated the short-term to midterm results of reoperation with bearing change to metal-on-polyethylene (MoP) after ceramic bearing fracture in ceramic-on-ceramic total hip arthroplasty. Nine third-generation ceramic bearing fractures (6 heads and 3 liners) were treated with bearing change to MoP. Mean age at reoperation was 52.7 years. Mean follow-up was 4.3 years. During follow-up, 2 of 3 liner-fractured hips and 1 of 6 head-fractured hips showed radiologic signs of metallosis and elevated serum chromium levels. Re-reoperation with bearing rechange to a ceramic head was performed for the hips with metallosis. One liner-fractured hip had periprosthetic joint infection. Dislocation occurred in 3 hips. From our experience, bearing change to MoP is not a recommended treatment option for ceramic bearing fracture in total hip arthroplasty.
    The Journal of arthroplasty 09/2015; DOI:10.1016/j.arth.2015.08.039 · 2.67 Impact Factor
  • Ji-Hye Lee · Jinwoo Nam · Hee Joong Kim · Jeong Joon Yoo ·
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    ABSTRACT: For successful tissue regeneration, effective cell delivery to defect site is very important. Various types of polymer biomaterials have been developed and applied for effective cell delivery. PLGA (poly lactic-co-glycolic acid), a synthetic polymer, is a commercially available and FDA approved material. Platelet-rich plasma (PRP) is an autologous growth factor cocktail containing various growth factors including PDGF, TGFβ-1 and BMPs, and has shown positive effects on cell behaviors. We hypothesized that PRP pretreatment on PLGA mesh using different methods would cause different patterns of platelet adhesion and stages which would modulate cell adhesion and proliferation on the PLGA mesh. In this study, we pretreated PRP on PLGA using three different methods including simple dripping (SD), dynamic oscillation (DO) and centrifugation (CE), then observed the amount of adhered platelets and their activation stage distribution. The highest amount of platelets was observed on CE mesh and calcium treated CE mesh. Moreover, calcium addition after PRP coating triggered dramatic activation of platelets which showed large and flat morphologies of platelets with rich fibrin networks. Human chondrocytes (hCs) and human bone marrow stromal cells (hBMSCs) were next cultured on PRP-pretreated PLGA meshes using different preparation methods. CE mesh showed a significant increase in the initial cell adhesion of hCs and proliferation of hBMSCs compared with SD and DO meshes. The results demonstrated that the centrifugation method can be considered as a promising coating method to introduce PRP on PLGA polymeric material which could improve cell-material interaction using a simple method.
    Biomedical Materials 04/2015; 10(2):025002. DOI:10.1088/1748-6041/10/2/025002 · 3.70 Impact Factor
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    ABSTRACT: Wear cannot be completely prevented after total hip arthroplasty. If severe polyethylene (PE) liner wear develops, the so-called catastrophic failure occurs and metallosis develops. We postulated that longevity of the new implant may be affected after revision surgery for metallosis following a catastrophic failure of a PE liner due to the substantial amount of PE wear particles and infiltration of the metal particles in this catastrophic condition. Twenty-three hips of 23 patients were identified because they showed metallosis during revision total hip arthroplasties performed in Seoul National University Hospital between January 1996 and August 2004. They were followed for at least 6.5 years after the index revision total hip arthroplasty. The clinical and radiological results of revision total hip arthroplasties in these patients were evaluated. The median Harris hip score increased from 60 points before revision total hip arthroplasties to 90 points at the final follow-up. Osteolysis was detected at an average of 9.3 years after revision total hip arthroplasties in 13 hips and acetabular cup loosening at average 9.8 years after revision total hip arthroplasties in 9 hips. With radiographic evidence of osteolysis and loosening as the end points, the 15-year survival rates were 28.2% and 56.0%, respectively. The survival rate of revision total hip arthroplasty in patients with metallosis following a catastrophic failure of a PE liner was low.
    Clinics in orthopedic surgery 03/2015; 7(1):46-53. DOI:10.4055/cios.2015.7.1.46
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    ABSTRACT: We designed this study to demonstrate recent trends in the proportion of adult hip research in orthopedics, to identify countries leading the adult hip research, and to evaluate the relationship between the economic power of the countries and their contributions. Studies published in seven select orthopedic journals were retrieved from PubMed. Among them, we determined the number of adult hip studies. The countries-of-origin of adult hip studies, and the economic power of the countries were investigated. A total of 7218 orthopedic publications and 1993 (27.6%) addressed adult hip research were identified. Adult hip studies increased from 313 (23.7%) in 2000 to 555 (27.9%) in 2011. Twenty-five countries accounted for 97.6% of the total number of adult hip studies, and gross domestic product correlated with publication volume (Spearman's rho, 0.723; p=0.000). Researchers from a limited number of developed countries have published their studies in the adult hip discipline.
    Yonsei Medical Journal 01/2015; 56(1):132-8. DOI:10.3349/ymj.2015.56.1.132 · 1.29 Impact Factor
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    ABSTRACT: We analyzed national data collected by the Health Insurance Review and Assessment Service in Korea from 2007 to 2011; 1) to document procedural numbers and procedural rate of bipolar hemiarthroplasty (BH), primary and revision total hip arthroplasties (THAs), 2) to stratify the prevalence of each procedure by age, gender, and hospital type, and quantified, 3) to estimate the revision burden and evaluate whether the burden is changed over time. Our final study population included 60,230 BHs, 40,760 primary THAs, and 10,341 revision THAs. From 2007 to 2011, both the number and the rate of BHs, primary THAs increased steadily, whereas there was no significant change in revision THAs. Over the 5 yr, the rate of BHs and primary THAs per 100,000 persons significantly increased by 33.2% and 21.4%, respectively. The number of revision THAs was consistent over time. The overall annual revision burden for THA decreased from 22.1% in 2007 to 18.9% in 2011. In contrast to western data, there were no changes in the number and rate of revision THAs, and the rates of primary and revision THAs were higher for men than those for women. Although 5 yr is a short time to determine a change in the revision burden, there have been significant decreases in some age groups. Graphical Abstract
    Journal of Korean Medical Science 06/2014; 29(6):852-8. DOI:10.3346/jkms.2014.29.6.852 · 1.27 Impact Factor
  • Hong Suk Kwak · Jinwoo Nam · Ji-Hye Lee · Hee Joong Kim · Jeong Joon Yoo ·
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    ABSTRACT: The objective of this study was to test the hypothesis that platelet-rich plasma (PRP) pretreatment on a poly-lactic-co-glycolic acid (PLGA) mesh scaffold enhances the healing capacity of the meniscus with human chondrocyte-seeded scaffolds in vivo, even when the seeded number of cells was reduced from 10 million to one million. A flexible PLGA mesh scaffold was pretreated with PRP using a centrifugal technique. One million human articular chondrocytes were seeded onto the scaffold by dynamic oscillation. After 7 days, scaffolds were placed between human meniscal discs and were implanted subcutaneously in nude mice for 6 weeks (n = 16/group). Fluorescence microscopy demonstrated uniform attachment of the chondrocytes throughout the scaffolds 24 h following seeding. Cell attachment analysis revealed a significantly increased number of chondrocytes on PRP-pretreated than non-treated scaffolds (p < 0.05). Field emission scanning electron microscopy revealed chondrocytes attached to the PRP-pretreated scaffolds interconnecting their cellular processes with the fibrin network at 24 h and day 7 of culture. Of the 16 constructs containing PRP-pretreated scaffolds implanted in mice, six menisci healed completely, nine healed incompletely and one did not heal. Histological results from the 16 control constructs containing non-treated scaffolds revealed that none had healed completely, four healed incompletely and 12 did not heal. The histological outcome between the groups was significantly different (p < 0.05). These findings suggest that human articular chondrocytes on PRP-pretreated PLGA mesh scaffolds demonstrate increased cell attachment and enhance the healing capacity of meniscus with a reduced number of seeding cells in a meniscal repair mouse model. Copyright © 2014 John Wiley & Sons, Ltd.
    Journal of Tissue Engineering and Regenerative Medicine 06/2014; DOI:10.1002/term.1938 · 5.20 Impact Factor
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    Pil Whan Yoon · Hong Suk Kwak · Jeong Joon Yoo · Kang Sup Yoon · Hee Joong Kim ·
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    ABSTRACT: We evaluated the clinical course of subchondral insufficiency fracture of the femoral head (SIFFH) and its characteristic findings with special regard to joint space narrowing (JSN). Thirty-one cases of SIFFH of mean age 68.9 yr initially underwent limited weight-bearing conservative treatment. During the follow-up period, the patients with intractable pain underwent total hip arthroplasty (THA). For radiographic evaluation, lateral center-edge angle, JSN and femoral head collapse (FHC) were documented, and the extent of FHC was classified as mild (<2 mm), moderate (2-4 mm), and severe (>4 mm). The progression or new development of FHC more than 2 mm was evaluated on sequential plain radiographs. The relationship between radiographic parameters and clinical outcomes were evaluated. THAs were performed in 15 cases (48.4%). There was no significant correlation between clinical outcomes and the extent of initial FHC. However, a significantly larger proportion of patients that underwent THA showed JSN and FHC progression compared to the symptom improvement group. The risk factor significantly associated with failed conservative treatment was JSN (P=0.038; OR, 11.8; 95% CI, 1.15-122.26). Clinical results of conservative treatment for SIFFH in elderly patients are relatively poor. The patients with JSN are at higher risk of failed conservative treatment. Graphical Abstract
    Journal of Korean medical science 04/2014; 29(4):593-8. DOI:10.3346/jkms.2014.29.4.593 · 1.27 Impact Factor
  • Jeong Joon Yoo · Hee Joong Kim · Sang-Min Seo · Kyung-Sik Oh ·
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    ABSTRACT: A hemiporous hydroxyapatite (HAp) scaffold was prepared to support the tissue engineered approach to the restoration of damaged bone. The scaffold comprised a porous cell-seeded part and a non-porous load bearing part. A wet processing technique of HAp suspensions was used to shape the hemiporous body. The structure of the porous part was tailored using a stack of heat treated porogen placed on the plaster. The prepared specimen had approximately 30 layers of connected pores, which could accommodate sufficient human bone marrow stromal cells (hBMSCs). The result of an in vitro test showed that hBMSCs successfully proliferated and produced extracellular matrices even at the pore in the deep portion of the scaffolds. The in vivo test in the distal femur of a rabbit showed the formation of new fibrous tissue and tubular vessels with red blood cells in the hBMSCs-seeded scaffold from the pores at the deepest portion as well as from the pore at the periphery of the scaffold. The result was in distinct contrast with the scaffold without cell loading. The preloading of cell was thus very effective in the migration of cells in spite of the unconfirmed connectivity among pores. The present casting approach had the merits of simplicity and versatility in tailoring the scaffold structure without an elaborate device. (c) 2013 Elsevier Ltd and Techna Group S.r.l. All rights reserved.
    Ceramics International 03/2014; 40(2):3079-3087. DOI:10.1016/j.ceramint.2013.09.138 · 2.61 Impact Factor
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    ABSTRACT: This study was undertaken to determine incidence, associated risk factors, and clinical outcomes of a diastasis of pubic symphysis. Among 4,151 women, who delivered 4,554 babies at the Department of Obstetrics of Seoul National University Bundang hospital from January 2004 to December 2006, eleven women were diagnosed as having a symptomatic diastasis of pubic symphysis. We estimated the incidence of the diastasis and identified the associated risk factors. To evaluate the pain relief and reduction of diastasis we followed up the 11 diastatic patients. The incidence of the diastasis was 1/385. Primiparity (P = 0.010) and twin gestation (P = 0.016) appeared as risk factors for diastasis by univairable analysis; and twin gestation appeared to be the only risk factor (P = 0.006) by logistic analysis. Two patients were operated due to intractable pain; and the remaining nine patients were treated conservatively. The diastatic gap decreased to less than 1.5 cm by 2 to 6 weeks after the diagnosis and then remained stationary. At a mean follow-up of 22.1 months (range, 12 to 47 months), five of 11 patients had persistent symphysis pubis dysfunction. Diastasis is more frequent than generally acknowledged. Pregnant women with multiple gestations should be informed about the potential risk of pubic symphysis diastasis.
    Journal of Korean medical science 02/2014; 29(2):281-6. DOI:10.3346/jkms.2014.29.2.281 · 1.27 Impact Factor
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    ABSTRACT: Patients with residual poliomyelitis can have advanced degenerative arthritis of the hip in the paralytic limb or the nonparalytic contralateral limb. Although THA is a treatment option for some of these patients, there are few studies regarding THA in this patient population. We therefore reviewed a group of patients with residual poliomyelitis who underwent cementless THA on either their paralytic limb or nonparalytic limb to assess (1) Harris hip scores, (2) radiographic results, including implant loosening, (3) complications, including dislocation, and (4) limb length discrepancy after recovery from surgery. From January 2000 to December 2009, 10 patients with residual poliomyelitis (10 hips, four paralytic limbs and six nonparalytic contralateral limbs) underwent THA using cementless prostheses. Harris hip scores, complications, and leg length discrepancy were determined by chart review, and confirmed by questionnaire and examination; radiographs were reviewed by two observers for this study. Followup was available for all 10 patients at a minimum of 3 years (median, 7 years; range, 3.4-13 years). Surgery was done at the same side of the paralytic limb in four hips and contralateral to the paralytic limb in six. All patients had pain relief and improvement in function; the Harris hip score improved from mean of 68 preoperatively to 92 at last followup (p = 0.043). However, only three patients had complete pain relief. One hip dislocated, which was treated successfully with closed reduction and a hip spica cast for 2 months. There was no loosening or osteolysis in this series. Leg length discrepancy improved after the index operation, but only in the THAs performed in the paralytic limbs. Cementless THA may be suitable for painful hips in adult patients with residual poliomyelitis. Nonetheless, these patients should be informed of the possibility of mild residual pain and persistent leg length discrepancy, particularly patients whose THA is performed on the limb that was not affected by polio (ie, the nonparalytic contralateral limb). Level IV, therapeutic study. See the Instructions for Authors for a complete description of levels of evidence.
    Clinical Orthopaedics and Related Research 11/2013; 472(3). DOI:10.1007/s11999-013-3338-3 · 2.77 Impact Factor
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    ABSTRACT: Total hip arthroplasty (THA) for severe developmental dysplasia of the hip (DDH) is a technically demanding procedure for arthroplasty surgeons, and it is often difficult to reduce the hip joint without soft tissue release due to severe flexion contracture. We performed two-stage THAs in irreducible hips with expected lengthening of the affected limb after THA of over 2.5 cm or with flexion contractures of greater than 30 degrees in order to place the acetabular cup in the true acetabulum and to prevent neurologic deficits associated with acute elongation of the limb. The purpose of this study is to evaluate the outcomes of cementless THA in patients with severe DDH with a special focus on the results of two-stage THA. Retrospective clinical and radiological evaluations were done on 17 patients with Crowe type III or IV developmental DDH treated by THA. There were 14 women and 3 men with a mean age of 52.3 years. Follow-ups averaged 52 months. Six cases were treated with two-stage THA followed by surgical hip liberalization and skeletal traction for 2 weeks. The mean Harris hip score improved from 40.9 to 89.1, and mean leg length discrepancy (LLD) in 13 unilateral cases was reduced from 2.95 to 0.8 cm. In the patients who underwent two-stage surgery, no nerve palsy was observed, and the single one-stage patient with incomplete peroneal nerve palsy recovered fully 4 weeks postoperatively. The short-term clinical and radiographic outcomes of primary cementless THA for patients with Crowe type III or IV DDH were encouraging. Two-stage THA followed by skeletal traction after soft tissue release could provide alternative solutions to the minimization of limb shortenings or LLD without neurologic deficits in highly selected patients.
    Clinics in orthopedic surgery 09/2013; 5(3):167-73. DOI:10.4055/cios.2013.5.3.167
  • Pil Whan Yoon · Ji Eun Kwon · Jeong Joon Yoo · Hee Joong Kim · Kang Sup Yoon ·
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    ABSTRACT: OBJECTIVES:: To evaluate the incidence of femoral neck fracture (FNF) after removal of a compression hip screw (CHS) without trauma and to determine the risk factors for this type of fracture. DESIGN:: Retrospective study of consecutive patient series SETTING:: University teaching hospital PATIENTS:: Sixty-seven patients with a mean age of 65.3 years (45 women and 22 men). INTERVENTION:: A total of 67 implants were removed in the presence of bony consolidation of the fracture site; most of them were due to hardware pain. MAIN OUTCOME MEASURES:: The incidence of FNF after a CHS removal, clinical parameters (age, gender, bone mineral density, body mass index, fracture stability), and radiological parameters (the femoral neck-shaft angle, femoral neck width, distance between thread of lag screw and neck cortex). Univariate analysis was performed for those parameters of the fracture group and the non-fracture group. To assess which variables were associated with FNF, a multiple logistic regression was used. RESULTS:: Six (9.0 %) FNFs occurred within 1 month after a CHS removal. The mean anterior and lateral neck widths were significantly smaller, and the mean anterior and inferior thread-to-cortex distances were significantly shorter in the fracture group compared with the non-fracture group. The risk factor significantly associated with FNF was the inferior thread-to-cortex distance (OR 0.462; 95% CI: 0.217; 0.988). CONCLUSIONS:: CHS should not be removed routinely due to the risk of FNF. Furthermore, attention should be paid to at risk patients with a hip screw positioned close to the inferior femoral neck cortex.
    Journal of orthopaedic trauma 05/2013; 27(12). DOI:10.1097/BOT.0b013e31829906a0 · 1.80 Impact Factor
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    Osung Lee · Jeong Joon Yoo · Hee Joong Kim ·
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    ABSTRACT: The goal of this study was to analyze the short to midterm results of Bernese periacetabular osteotomy for the patient with hip dysplasia.
    The Journal of the Korean Orthopaedic Association 01/2013; 48(6):433. DOI:10.4055/jkoa.2013.48.6.433
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    ABSTRACT: Purpose: In an alumina-on-alumina total hip arthroplasty (THA), recommended with a small inclination angle <45°, the acetabular component (cup) may be positioned more medially to be covered almost completely by host bone. The purpose of this study was to identify the correlating factors and to evaluate the outcomes of medial placement of the cup in patients with alumina-on-alumina THAs. Methods: Using the propensity score matching with age, gender, body mass index, initial diagnosis, and the length of follow-up as variables, 38 hips with a medialized cup and 38 hips with a non-medialized one were identified from 389 hips in 347 who patients underwent primary alumina-on-alumina THA and followed up for more than 7 years. Clinical and radiological outcomes were compared between the two groups. Results: Preoperative acetabular medial wall thickness and the cup inclination angle were significantly smaller in the medialization group compared to the non-medialization group. Center edge angle, cup size, and coverage by host bone were not significantly different between the two groups. The hip center of rotation was significantly medialized in the medialization group. The Harris hip scores were not significantly different between the two groups. No component loosening or osteolysis was observed and no revision was required in either groups. Conclusions: Thin acetabular medial wall and a small inclination angle of the cup were the correlating factors of medial placement of the cup in patients who underwent an alumina-on-alumina THA. Medial placement did not lead to differences in the clinical or radiological outcomes.
    Archives of Orthopaedic and Trauma Surgery 12/2012; 133(3). DOI:10.1007/s00402-012-1661-x · 1.60 Impact Factor
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    ABSTRACT: Umbilical cord blood (UCB) has recently been recognized as a new source of mesenchymal stem cells (MSCs) for use in stem cell therapy. We studied the effects of systemic injection of human UCB-MSCs and their conditioned medium (CM) on ovariectomy (OVX)-induced bone loss in nude mice. Ten-week-old female nude mice were divided into six groups: Sham-operated mice treated with vehicle (Sham-Vehicle), OVX mice subjected to UCB-MSCs (OVX-MSC) or human dermal fibroblasts (OVX-DFB) transplantation, OVX mice treated with UCB-MSCs CM (OVX-CM), zoledronate (OVX-Zol), or vehicle (OVX-Vehicle). Although OVX-Vehicle group exhibited significantly less bone mineral density (BMD) gain compared with Sham-Vehicle group, transplantation of hUCB-MSCs (OVX-MSC group) has effectively prevented OVX-induced bone mass attenuation. Notably, OVX-CM group also showed BMD preservation comparable to the OVX-MSC group. In addition, micro-CT analysis demonstrated improved trabecular parameters in both OVX-MSC and OVX-CM groups compared to OVX-Vehicle or OVX-DFB group. Histomorphometric analysis showed increased bone formation parameters, accompanied by increased serum procollagen type-I N-telopeptide levels in OVX-MSC and OVX-CM mice. However, cell trafficking analysis failed to demonstrate engraftment of MSCs in bone tissue 48 hrs after cell infusion. In vitro, hUCB-MSC CM increased alkaline phosphatase activity in human bone marrow-derived MSCs and mRNA expression of collagen type 1, Runx2, osterix, and alkaline phosphatase in C3H10T1/2 cells. Furthermore, hUCB-MSC CM significantly increased survival of osteocyte-like MLO-Y4 cells while it inhibited osteoclastic differentiation. To summarize, transplantation of hUCB-MSCs could effectively prevented OVX-mediated bone loss in nude mice which appears to be mediated by paracrine mechanism rather than direct engraftment of the MSCs.
    Tissue Engineering Part A 12/2012; 19(5-6). DOI:10.1089/ten.TEA.2012.0047 · 4.64 Impact Factor
  • Juyoung Kim · Hyeong Jo Yoon · Jeong Joon Yoo · Hee Joong Kim ·
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    ABSTRACT: OBJECTIVES:: We evaluated isolated fractures of the greater trochanter (IFGT) on plain radiographs with multiplanar reformation computed tomography (MPR CT). DESIGN:: Retrospective review of patients SETTING:: University teaching hospital PATIENTS:: This study included 27 consecutive patients with apparently isolated fractures of the greater trochanter MAIN OUTCOME MEASUREMENTS:: The clinical results, X-ray, CT, MRI, bone scintigraphy findings were investigated RESULTS:: Four of 27 cases demonstrated anterior cortical breakage or extensive damage of the trabecular bone in the intertrochanteric area on MPR CT images. Surgical fixation was necessary for these four cases. The other 23 cases, in which no structural damage was detected, were treated conservatively and the results were satisfactory without progression to a complete intertrochanteric fracture.All 9 cases evaluated with MR imaging demonstrated extension into the intertrochanteric area. In 5 cases, the extension crossed the midline on the mid-coronal image. Two of the cases were treated surgically because of anterior cortical breakage and extensive trabecular impaction on MPR CT, respectively. However, the other 3 cases and 4 cases with mild intertrochanteric extension were treated conservatively without problem. CONCLUSIONS:: The evaluation of IFGT with MPR CT was shown to be valuable for determining the optimal treatment method.
    Journal of orthopaedic trauma 11/2012; 27(8). DOI:10.1097/BOT.0b013e31827d0ad8 · 1.80 Impact Factor
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    ABSTRACT: We evaluated the outcomes of 64 consecutive revision total hip arthroplasties with an alumina-on-alumina bearing surface in 61 patients with osteolysis. No implants had been rerevised nor was osteolysis detected at a mean of 9.8 years (range, 7.0-13.1 years) postoperatively. There was 1 case of stem loosening but no cup loosening or alumina bearing fractures. Two surgical procedures were performed for an infection in 1 patient. Three dislocations occurred in 3 hips; all were treated with closed reduction and abduction bracing for 3 months. No further dislocations occurred. With any reoperation or radiographic evidence of osteolysis or loosening as the end point, the 7-year survival rate was 96.9% (95% confidence interval, 90.8%-100%). The alumina-on-alumina bearing surfaces used for revision total hip arthroplasty in patients with osteolysis were found to produce encouraging clinical results and implant survival rates at a minimum of 7 years postoperatively.
    The Journal of arthroplasty 11/2012; 28(1). DOI:10.1016/j.arth.2012.04.030 · 2.67 Impact Factor
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    ABSTRACT: The distal femur is a common site for benign or malignant bone tumors in children or adolescents. Distal femoral cortical irregularities at the posterior aspect of the distal femoral metaphysis must be differentiated from malignant bone tumors because they might be misinterpreted as malignant neoplasm. Plain radiographs of a 6-year-old girl complaining of left knee pain for 4 weeks showed cortical proliferation with excavation on her distal femoral metaphysis. Computed tomography, magnetic resonance imaging and bone scan helped to differentiate the cortical irregularity from malignant lesions. Therefore unnecessary invasive surgery was avoided in this patient.
    European Journal of Orthopaedic Surgery & Traumatology 11/2012; 23 Suppl 2. DOI:10.1007/s00590-012-1122-9 · 0.18 Impact Factor
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    ABSTRACT: Wet processing of hydroxyapatite is useful in the preparation of a green body with a complex structure such as a porous body. For successful wet processing, a suspension with low viscosity and high solid loading is essential. The optimization of the suspension is typically achieved through the careful control of the parameters such as the amount of dispersant and the pH. The milling time was also presented as a significant parameter for the preparation of the suspension in this work. Excessive milling brought about an increase in viscosity, which subsequently resulted in a green body with reduced density. Due to the loose network of primary particles in the green body, the densification was not successfully achieved. The loose packing in the green body was attributed to the reduction of the absolute zeta potential with the increase in milling time.
    Current Applied Physics 09/2012; 12:S71–S75. DOI:10.1016/j.cap.2012.02.023 · 2.21 Impact Factor
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    ABSTRACT: BACKGROUND: THA in patients younger than 30 years presents challenges because of uncertainties regarding the long-term survivorship of prostheses. Alumina-on-alumina bearings, which exhibit little long-term wear, may be a reasonable option but the long-term survivorship is unknown. QUESTIONS/PURPOSES: We determined (1) the survival rate of alumina-on-alumina bearings in patients younger than 30 years after a 10-year followup, (2) the incidence of audible hip clicking and squeaking, (3) radiographic evidence of osteolysis, and (4) the effects on pregnancy, childbirth, and career choice. METHODS: We retrospectively reviewed 62 patients who had 75 THAs with alumina-on-alumina bearings followed more than 10 years (average, 11.5; range, 10-13.5 years). Mean patient age at the time of surgery was 24 years (range, 18-30 years). All operations were performed using the same cementless implant at a single center. We determined survival, presence of osteolysis, and function (Harris hip score, WOMAC). RESULTS: The 10-year survival rate of alumina-on-alumina bearings in THAs, with revision for any reason as the end point, was 98.9%. Audible hip clicking and squeaking were identified in 10 hips and two hips, respectively. No osteolysis was detected. None of the 11 patients who became pregnant had been affected by their THA during pregnancy or childbirth. Seven of the 14 patients who were unemployed at the time of index surgery stated that their THA affected their job choice. CONCLUSIONS: We found a high 10-year survival of cementless alumina-on-alumina bearings in THAs in patients younger than 30 years. Lifetime events such as job choice, pregnancy, and childbirth should be considered when choosing THA for patients younger than 30 years. LEVEL OF EVIDENCE: Level IV, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.
    Clinical Orthopaedics and Related Research 07/2012; 470(12). DOI:10.1007/s11999-012-2493-2 · 2.77 Impact Factor

Publication Stats

749 Citations
162.07 Total Impact Points


  • 2007-2015
    • Seoul National University
      • • Medical Research Center
      • • Department of Orthopaedic Surgery
      Sŏul, Seoul, South Korea
    • Gyeongsang National University
      Shinshū, Gyeongsangnam-do, South Korea
  • 2003-2015
    • Seoul National University Hospital
      • Department of Orthopedic Surgery
      Sŏul, Seoul, South Korea
  • 2011
    • Harvard University
      Cambridge, Massachusetts, United States

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