Biomedical subjects

Shin-Yoon Kim

Publications and source records attributed to Shin-Yoon Kim.

At least 19 recordsLinked to original sources

PubMed2007

Ceramic liner fracture after cementless alumina-on-alumina total hip arthroplasty.

Advances in technology have reduced the risk of fracture of ceramic total hip arthroplasty implants, but concerns remain about fracture of both components. We retrospectively reviewed 133 patients (157 hips) who had cementless alumina-on-alumina total hip arthroplasties with a sandwich-type acetabular component. Six patients (seven hips) died and five patients (six hips) were interviewed by telephone (95% followup). The 122 patients (144 hips) examined had a minimum followup of 36 months (average, 45 months; range, 36-68 months). All acetabular cups and femoral stems were radiographically stable at the last followup. Five hips in five patients (3.5%) were revised because of ceramic liner fractures. Ceramic liner fractures occurred at a mean of 35 months (range, 24-48 months) postoperatively. Acetabular cups in the fracture group (n = 5) were more anteverted than those in the nonfracture group (n = 139). In three patients the fracture apparently occurred during squatting, resulting in hyperflexion and wide hip abduction. Early ceramic liner fracture was associated with impingement associated with excessive anteversion of the acetabular cup in Korean patients who habitually squat.

Adolescent↗

PubMed2007

Associations of catalase gene polymorphisms with bone mineral density and bone turnover markers in postmenopausal women.

BACKGROUND: Oxidative stress has been recently suggested to play a part in the development of osteoporosis. Catalase is a major antioxidant enzyme that detoxifies hydrogen peroxide by converting it into water and oxygen, thereby preventing cellular injury by oxidative stress. AIMS: To examine the associations between the catalase gene (CAT) polymorphisms and bone mineral density (BMD) and bone turnover markers in postmenopausal Korean women. METHODS: All exons, their boundaries and the promoter region (approximately 1.5 kb) were directly sequenced in 24 individuals. Among 18 variants identified by a direct sequence method, four polymorphisms were selected and genotyped in all study participants (n = 560). BMD at the lumbar spine and proximal femur was measured using dual-energy x ray absorptiometry. Serum osteocalcin concentrations and bone-specific alkaline phosphatase activity were determined by an immunoradiometric assay and an immunoassay, respectively. RESULTS: The mean (standard deviation) age of the participants was 59.4 (7.2) years. Multivariate analysis showed an association of the +22348C-->T polymorphism with BMD at the lumbar spine (p = 0.01 in the dominant model) and at femur neck (p = 0.05 in the dominant model), and with serum osteocalcin level (p = 0.008 in the dominant model). Haplotype analyses showed that HT4 (-20T, +144C, +22348T, +33078A) was significantly associated with higher BMD at various sites (p<0.001-0.03) and with lower serum osteocalcin levels (p = 0.01 in the codominant model). CONCLUSIONS: These findings indicate that the +22348C-->T polymorphism and HT4 of CAT may be useful genetic markers for bone metabolism.

Aged↗

PubMed2006

Methionine synthase reductase polymorphisms are associated with serum osteocalcin levels in postmenopausal women.

Homocysteine (Hcy) is thought to play an important role in the development of osteoporosis and fracture. Methionine synthase reductase (MTRR) is an enzyme involved in the conversion of Hcy to methionine. We hypothesized that certain genetic polymorphisms of MTRR leading to reduced enzyme activity may cause hyperhomocysteinemia and affect bone metabolism. We therefore examined the associations of the A66G and C524T polymorphisms of the MTRR gene with bone mineral density (BMD) and serum osteocalcin levels in postmenopausal women. Although we did not detect any significant associations between MTRR polymorphisms and BMD or serum osteocalcin levels, we found that the 66G/524C haplotype, which has reduced enzyme activity, was significantly associated with serum osteocalcin levels in a gene-dose dependent manner (P = 0.002). That is, the highest osteocalcin levels (34.5 +/- 16.8 ng/ml) were observed in subjects bearing two copies, intermediate osteocalcin levels (32.6 +/- 14.4 ng/ml) were observed in subjects bearing one copy, and the lowest levels of osteocalcin (28.8 +/- 10.9 ng/ml) were observed in subjects bearing no copies. These results suggest that the 66G/524C haplotype of the MTRR gene affect bone turn over rate.

Aged↗

PubMed2006

TGF-beta2 stimulates cranial suture closure through activation of the Erk-MAPK pathway.

Cranial sutures are important growth sites of the skull. During suture closure, the dura mater is one of the most important sources of various positive and negative regulatory signals. Previous results indicate that TGF-beta2 from dura mater strongly accelerates suture closure, however, its exact regulatory mechanism is still unclear. In this study, we confirmed that removal of dura mater in calvarial organ culture strongly accelerates sagittal suture closure and that this effect is further enhanced by TGF-beta2 treatment. TGF-beta2 stimulated cell proliferation in the MC3T3-E1 cell line. Similarly, it stimulated the proliferation of cells in the sutural space in calvarial organ culture. Furthermore, TGF-beta2-mediated enhanced cell proliferation and suture closure were almost completely inhibited by an Erk-MAPK blocker, PD98059. These results indicate that TGF-beta2-induced activation of Erk-MAPK is an important signaling component that stimulates cell proliferation to enrich osteoprogenitor cells, thereby promoting their differentiation into osteoblasts to achieve a rapid calvarial bone expansion.

Animals↗

PubMed2006

Retrograde nailing with subsequent screw fixation for ipsilateral femoral shaft and neck fractures.

INTRODUCTION: Although ipsilateral femoral shaft and neck fractures are difficult to treat, there is still no consensus on the optimal treatment of this complex injury. We report the results of treating the 17 fractures with a standard protocol of retrograde nailing for diaphyseal fractures and subsequent screw fixation for the femoral neck fractures. MATERIALS AND METHODS: Seventeen injuries (16 patients) sustained femoral shaft fractures, which were treated with retrograde intramedullary nails and subsequent screw fixation. Femoral neck fracture was noted before the operation in all patients except one. A femoral shaft fracture was always addressed first with unreamed retrograde nailing. Then, the femoral neck fracture was treated by cannulated screws or dynamic hip screw according to the level of fracture. RESULTS: The average time for union of femoral shaft fractures was 27.3 (14-60) weeks. Nonunion occurred in five patients, who required bone grafts or changes of fixation. The average time for union of femoral neck fractures was 11 (8-12) weeks. All united, except for one case of nonunion with avascuar necrosis, which was a Garden stage IV fracture. Functional results using Friedman-Wyman criteria were good in 16 cases, and fair in one. The only fair result was nonunion of the femoral neck, which had the joint arthroplasty. CONCLUSION: Retrograde nailing of femoral shaft fractures can provide an easy fixation and a favorable result for ipsilateral femoral neck fractures.

Adult↗

PubMed2006

Four novel RUNX2 mutations including a splice donor site result in the cleidocranial dysplasia phenotype.

Cleidocranial dysplasia (CCD) is an autosomal dominant disorder caused by haploinsufficiency of the RUNX2 gene. In this study, we analyzed by direct sequencing RUNX2 mutations from eleven CCD patients. Four of seven mutations were novel: two nonsense mutations resulted in a translational stop at codon 50 (Q50X) and 112 (E112X); a missense mutation converted arginine to glycine at codon 131 (R131G); and an exon 1 splice donor site mutation (donor splice site GT/AT, IVS1 + 1G > A) at exon 1-intron junction resulted in the deletion of QA stretch contained in exon 1 of RUNX2. We focused on the functional analysis of the IVS1 + 1G > A mutation. A full-length cDNA of this mutation was cloned (RUNX2Deltae1) and expressed in Chinese hamster ovary (CHO) and HeLa cells. Functional analysis of RUNX2Deltae1 was performed with respect to protein stability, nuclear localization, DNA binding, and transactivation activity of a downstream RUNX2 target gene. Protein stability of RUNX2Deltae1 is similar to wild-type RUNX2 as determined by Western blot analysis. Subcellular localization of RUNX2Deltae1, assessed by in situ immunofluorescent staining, was observed with partial retention in both the nucleus and cytoplasm. This finding is in contrast to RUNX2 wild-type, which is detected exclusively in the nucleus. DNA binding activity was also compromised by the RUNX2Deltae1 in gel shift assay. Finally, RUNX2Deltae1 blocked transactivation of the osteocalcin gene determined by transient transfection assay. Our findings demonstrate for the first time that the CCD phenotype can be caused by a splice site mutation, which results in the deletion of N-terminus amino acids containing the QA stretch in RUNX2 that contains a previously unidentified second nuclear localization signal (NLS). We postulate that the QA sequence unique to RUNX2 contributes to a competent structure of RUNX2 that is required for nuclear localization, DNA binding, and transactivation function.

Adolescent↗

PubMed2006

Results after operative treatment of transverse acetabular fractures.

BACKGROUND: Treatment of the transverse acetabular fracture is known to have worse results than other fracture types, although this fracture belongs to the elementary fracture group. The operative results of the transverse acetabular fracture, however, have not been well documented. To determine the results and factors that affect the choice of operative treatment for transverse acetabular fractures, we retrospectively reviewed 15 cases of transverse fracture. METHODS: A total of 15 patients had a transverse fracture, with an average follow-up period of 43 months; there were 8 patients with and 7 without a posterior wall fracture. There were 11 men and 4 women, with a mean age of 46.6 years. In seven cases there was also comminution of the weight-bearing dome. The surgical approaches used were the anterior ilioinguinal approach in 4 patients, the posterior approach in 10 patients, and the combined approach in 1 patient. Postoperative radiographic results were evaluated by Matta's criteria. Final clinical results were evaluated by a modified Merle d'Aubigne scoring system. RESULTS: All of the fractures healed. The average time for fracture healing was 17.5 weeks. Postoperative radiology revealed six cases of anatomical reduction, five cases of imperfect reduction, and four cases of poor reduction. According to the clinical results, nine patients had satisfactory results (three excellent, six good), and six had unsatisfactory results (three fair, three poor). Regarding complications, there were four cases of traumatic osteoarthritis and three of heterotopic ossification. The patients with an anatomical reduction had a higher satisfactory result rate. Comminution of the transverse fracture seemed to have an adverse influence on the postoperative radiologic result as well as a correlation with the development of traumatic arthritis. CONCLUSIONS: Transverse acetabular fractures, if not reduced anatomically, may have a tendency toward traumatic osteoarthritis and poor clinical outcome. Comminution of the dome may portend poor results.

Acetabulum↗

PubMed2006

Valgus intertrochanteric osteotomy for non-union of femoral neck fracture.

In spite of improved surgical techniques and fixation devices, non-union still reportedly occurs in 10-30% of cases of femoral neck fracture. A variety of methods of treatment that preserve the femoral head have been described, yet there are few reports on the results of valgus intertrochanteric osteotomy in cases of femoral neck non-union. We treated 11 such cases with valgus intertrochanteric osteotomy performed at one centre and using a single surgical technique. The cases were evaluated clinically and radiographically at a mean of 4.9 years. All of the non-unions were shown radiographically to have healed by an average of 12.5 weeks. Functional outcome was excellent for nine patients and poor for two who underwent subsequent total hip arthroplasty for avascular necrosis of the femoral head. We conclude that valgus intertrochanteric osteotomy is an effective treatment for femoral neck non-union, but avascular necrosis of the femoral head is a possible complication.

Adult↗

PubMed2006

Early failure of hemispheric hydroxyapatite-coated acetabular cups.

UNLABELLED: Total hip arthroplasties with hydroxyapatite coatings have shown encouraging results after early-term followup. We presumed hydroxyapatite-coating on a smooth hemispheric press-fit acetabular cup would enhance bone osseointegration and maintain stability of cup after midterm (minimum 5-year) followup. Sixty-three patients had 70 consecutive total hip arthroplasties. Five patients (eight hips) died from problems unrelated to surgery. The remaining patients (62 hips) were followed up for an average of 7 years (range, 6-9 years). The mean age of the patients was 49 years (range, 23-61 years). The average Harris hip score improved from 59 points (range, 32-82 points to 82 points (range, 37-100 points) at final followup. There were seven acetabular component revisions. Of the 55 unrevised cups, 47 hips (85%) were stable by bony ingrowth, five hips (9%) were fibrous stable, and three hips (5%) were unstable with cup migration. Osteolysis around the cup was observed in 18 hips (33%). The average polyethylene wear rate was 0.15 mm/year. Survival rates of the cups at 6 and 8 years were 94.3% and 60.5%, respectively. Total hip arthroplasties using an hydroxyapatite-coated smooth hemispheric acetabular cup showed an unexpected high failure rate in terms of fixation, occurrence of osteolysis, and revision after midterm followup. LEVEL OF EVIDENCE: Therapeutic study, Level IV (case series). See the Guidelines for Authors for a complete description of levels of evidence.

Acetabulum↗

PubMed2006

Lateral growth disturbance of the proximal femur in premature infants who had neonatal sepsis.

This is a retrospective review of four patients in whom a pattern of growth disturbance of the proximal femur with the bony bridge developed. They were born prematurely with low birth weight at birth and they had a suspicious sepsis, but they did not have any signs of localized infection. All presented with a progressive gait disturbance and a leg-length discrepancy. Radiographs showed an anterior tilting of the capital femoral epiphysis. Computed tomography and magnetic resonance imaging showed partial physeal closure with bony bridges. This case series suggests an association between neonatal sepsis of prematurity and growth disturbance of the proximal femur.

Developmental Disabilities↗

PubMed2006

Preparation and characterization of anodized titanium surfaces and their effect on osteoblast responses.

In this study, titanium (Ti) surface was modified by anodizing with a mixture of beta-glycerophosphate sodium and calcium (Ca) acetate, and the anodized surfaces were characterized by scanning electron microscopy, X-ray diffraction, and electron probe microanalysis. In vitro osteoblast response to anodized oxide was also evaluated. The anodic oxide produced was observed to have interconnected pores (0.5-2 microm in diameter) and intermediate roughness (0.60-1.00 microm). In addition, anodic oxide was observed to have amorphous and anatase oxide. Calcium and phosphorus ions were deposited on the Ti oxide during anodization. Osteoblast differentiation, as indicated by alkaline phosphatase production, was enhanced on anodized surfaces. It was thus concluded from this study that Ca phosphate can be deposited on Ti surfaces by anodization. It was also concluded that the phenotypic expression of osteoblast was enhanced by the presence of Ca phosphate and higher roughness on anodized Ti surfaces.

Acetates↗

PubMed2006

Prediction of collapse in femoral head osteonecrosis: a modified Kerboul method with use of magnetic resonance images.

BACKGROUND: The hypothesis that the combined necrotic angle measurement from magnetic resonance imaging scans predicts the subsequent risk of collapse in hips with femoral head necrosis was tested. METHODS: Thirty-seven hips with early stage osteonecrosis in thirty-three consecutive patients were investigated. With use of the modified method of Kerboul et al., we measured the arc of the femoral surface involved by necrosis on a midcoronal as well as a midsagittal magnetic resonance image (rather than an anteroposterior and a lateral radiograph) and then calculated the sum of the angles. On the basis of the magnitude of the resulting combined angle, hips were classified into four categories: grade 1 (<200 degrees), grade 2 (200 degrees to 249 degrees), grade 3 (250 degrees to 299 degrees), and grade 4 (>/=300 degrees). After the initial evaluations, the hips were randomly assigned to a core decompression group or a nonoperative group. Patients underwent regular follow-up until femoral head collapse or for a minimum of five years. RESULTS: Seven grade-4 hips and sixteen grade-3 hips had development of femoral head collapse by thirty-six months. Six of the nine grade-2 hips and none of the five grade-1 hips collapsed (log-rank test, p < 0.01). None of the four hips with a combined necrotic angle of </=190 degrees (the low-risk group) collapsed, all twenty-five hips with a combined necrotic angle of >/=240 degrees (the high-risk group) collapsed, and four (50%) of the eight hips with a combined necrotic angle between 190 degrees and 240 degrees (the moderate-risk group) collapsed during the study period. CONCLUSIONS: The Kerboul combined necrotic angle, as ascertained with use of magnetic resonance imaging scans instead of radiographs, is a good method to assess future collapse in hips with femoral head osteonecrosis. LEVEL OF EVIDENCE: Prognostic Level I. See Instructions to Authors on jbjs.org for a complete description of levels of evidence.

Adolescent↗

PubMed2005

Association study of semaphorin 7a (sema7a) polymorphisms with bone mineral density and fracture risk in postmenopausal Korean women.

Bone mineral density (BMD), the major factor determining bone strength, is closely related to osteoporotic fracture risk and is determined largely by multiple genetic factors. Semaphorin 7a (SEMA7A), a recently described member of the semaphorin family, has been shown to play a critical role in the activation of monocyte/macrophages that share progenitors with bone-resorbing osteoclasts and thus might contribute to osteoclast development. In the present study, we directly sequenced the SEMA7A gene in 24 Korean individuals, and identified 15 sequence variants. Five polymorphisms (+15667G > A, +15775C > G, +16285C > T, +19317C > T, +22331A > G) were selected and genotyped in postmenopausal Korean women (n = 560) together with measurement of the areal BMD (g/cm2) of the anterior-posterior lumbar spine and the non-dominant proximal femur using dual-energy X-ray absorptiometry. We found that polymorphisms of the SEMA7A gene were associated with the BMD of the lumbar spine and femoral neck. SEMA7A + 15775C > G and SEMA7A+22331A > G were associated with low BMD of the femoral neck (P = 0.02) and lumbar spine (P = 0.04) in a recessive model. SEMA7A-ht4 also showed an association with risk of vertebral fracture (OR = 1.87-1.93, P = 0.02-0.03). Our results suggest that variations in SEMA7A may play a role in decreased BMD and risk of vertebral fracture.

Absorptiometry, Photon↗

PubMed2005

The bone-related Zn finger transcription factor Osterix promotes proliferation of mesenchymal cells.

Osterix is a bone-related transcription factor that functions genetically downstream of Runx2, which controls both growth and differentiation in osteoblasts. Here we assessed the biological function of Osterix in mesenchymal cells that are not normally committed to the osteogenic lineage. Stably transfected NIH3T3 fibroblasts that express exogenous Osterix were examined for their ability to convert into osteoblastic cells by analyzing gene expression profiles of bone phenotype related markers, as well as by measuring bone nodule formation and cell proliferation. Forced expression of Osterix stimulates osteopontin gene expression but not the expression or activity of other bone-related markers, including collagen type I, alkaline phosphatase, osteocalcin, or osteonectin. Moreover, cells stably expressing Osterix do not induce bone nodule formation. Strikingly, both polyclonal and monoclonal cells expressing Osterix exhibit enhanced proliferation. Collectively, these results indicate that Osterix is insufficient to establish osteogenic lineage commitment, perhaps due to the ability of Osterix to promote cell growth. We propose that regulatory pathways operating upstream of or in parallel with Osterix are required for osteogenic conversion of uncommitted mesenchymal cells.

Animals↗

PubMed2005

Fatty marrow conversion of the proximal femoral metaphysis in transient bone marrow edema syndrome.

INTRODUCTION: In the proximal femoral metaphysis, hematopoietic marrow is predominant during the adult stage of life. The conversion of hematopoietic marrow to fatty marrow in the proximal femoral metaphysis has been suggested as an etiologic factor of ischemia in the pathogenesis of femoral head osteonecrosis. To determine whether the chronology of fatty marrow conversion of the proximal femoral metaphysis is related to transient bone marrow edema syndrome of the hip, a case control study was conducted on 10 patients with the disease. MATERIALS AND METHODS: There were 8 men and 2 women with a mean age of 33 years (range 19-45 years). The 10 patients were matched with 20 controls for gender and age (5-year range). T1-weighted MRI scans of their hips were reviewed. Marrow of the greater trochanter becomes fatty before puberty, and thus, the greater trochanter can be used as a built-in control. The signal intensity of the proximal femoral metaphysis was compared to that of the greater trochanter. RESULTS: In all patients, the signal intensity of the proximal femoral metaphysis was isointense (fatty marrow) relative to that of the greater trochanter. In control subjects, the signal intensity was isointense in 8 (40%) and hypointense (hematopoietic marrow) in 12 (60%) (p < 0.05). CONCLUSION: The current study shows that the proximal femoral metaphysis is predominantly fatty in transient bone marrow edema syndrome. The conversion of hematopoietic to fatty marrow is known to correlate with decreases in intramedullary blood flow. Thus, the current study suggests that an ischemia of the proximal femur secondary to fatty marrow conversion of the proximal femoral metaphysis might be a cause of transient bone marrow edema syndrome of the hip.

Adult↗

PubMed2005

Association of the OSCAR promoter polymorphism with BMD in postmenopausal women.

UNLABELLED: In an effort to identify genetic polymorphisms in potential candidate genes for osteoporosis, 10 variants were identified in the OSCAR gene using direct DNA sequencing, and 560 postmenopausal women were genotyped at five SNP loci, using the TaqMan method. The rare allele (G allele) of OSCAR-2322A>G (SNP in the 5' flanking region) showed significant association with lower BMD at various bone sites in postmenopausal women (n = 560). INTRODUCTION: BMD is the major factor for determining bone strength and osteoporotic fracture risk and is determined by both environmental and multiple genetic factors. The osteoclast-associated receptor (OSCAR) plays a critical role in osteoclast differentiation and thus is an important candidate gene for the modulation of BMD. MATERIALS AND METHODS: Through direct sequencing in 24 Korean individuals, 10 sequence variants were identified: 2 in the 5' flanking region, 7 in the exons (including 6 nonsynonymous single-nucleotide polymorphisms [SNPs]), and 1 in an intron. Five of these polymorphisms were selected for larger-scale genotyping in postmenopausal women (n = 560). Areal BMD (g/cm2) of the anterior-posterior lumbar spine and the nondominant proximal femur was measured using DXA (Lunar Expert XL and Hologic QDR 4500-A). Lateral thoracolumbar radiographs were obtained in all subjects. RESULTS: Using multiple regression analysis and controlling for age, years since menopause, height, weight, and evaluation machine as covariates, the rare allele (G allele) of OSCAR-2322A>G showed significant association with lower BMD at various bone sites in postmenopausal women. CONCLUSION: These findings suggest that the promoter variant in OSCAR gene (OSCAR-2322A>G) might be one of genetic determinants of BMD in postmenopausal women.

Absorptiometry, Photon↗

PubMed2005

Total hip arthroplasty with the use of nonmodular cementless acetabular component.

Sixty-seven hips in 63 patients who underwent total hip arthroplasties with the use of the nonmodular cementless acetabular component and alumina-on-polyethylene bearing surface were available for complete clinical and radiographic review at a mean follow-up period of 7 (range 5-9) years. The mean age was 59 years (range 34-75) years. The mean preoperative Harris hip score of 50 points improved to 93 points at final follow-up. One (1.5%) hip required revision for a recurrent dislocation. No component was loose radiographically at final follow-up. The mean linear wear rate was 0.07 (range 0.01-0.23) mm/y. At a mean follow-up of 7 years, there was no aseptic loosening. Further follow-up, however, is necessary to determine the potential advantage of nonmodular acetabular component for the development of pelvic osteolysis.

Adult↗

PubMed2005

Uncemented Harris-Galante total hip arthroplasty in patients with osteonecrosis of the femoral head. A 10-16-year follow-up study.

BACKGROUND: There have only been a few reports regarding the long-term results of uncemented THAs in patients with osteonecrosis. PATIENTS AND METHODS: We evaluated the long-term results of 65 consecutive uncemented total hip arthroplasties (Harris-Galante type I prostheses) in 54 men (59 hips) and 5 women (6 hips) with osteonecrosis of the femoral head. The mean age was 53 (33-64) years. The mean duration of follow-up was 12.5 (10-16) years. RESULTS: 9 femoral stems and 3 acetabular metal shells were revised. 2 polyethylene liners were changed due to excessive wear. A girdlestone procedure was done in 2 patients (2 hips) due to delayed deep infection. The mean polyethylene wear was 0.14 mm per year. 3 non-revised hips had pelvic osteolysis and 18 had femoral osteolysis. The 15-year survival rates, using failure defined as the removal of any component for any reason, were 85 (95% CI; 79-91)% for the acetabular and 80 (74-86)% for the femoral component and 70 (63-77)% for any of the components. INTERPRETATION: The first generation of the HGP design was frequently associated with pain, unstable fixation, and osteolysis. Excessive wear was frequent. The cup showed better durability than the stem.

Adult↗