Publications (10)17.59 Total impact
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Article: Structural, densitometric and biomechanical evaluations of Chinese patients with long-term bisphosphonate treatment.
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ABSTRACT: The association of long-term bisphosphonate treatment for osteoporosis and related safety problems such as atypical fractures were not clearly defined. This study was to evaluate the structural, densitometric and biomechanical properties of the prolonged bisphosphonate-loaded bones. Bone mineral density (BMD) at hip and femoral midshaft, bone cross-sectional area, moment of inertia of both femurs, bone formation and resorption biochemical markers were compared between 28 elderly with at least 4 years of bisphosphonate treatment from 2002 through 2006 and age-matched group of 37 elderly. The total hip BMD and t-score were found not different between two groups. However, bisphosphonate treated patients were found to have significantly lower bone mineral content in the femoral shaft (P < 0.05); morphological study showed lower cross-sectional area in subtrochanteric and mid-diaphyseal region and thus significantly lower moment of inertia (P < 0.01). High resolution-peripheral quantitative computed tomography showed significantly decreased trabecular density, bone volume ratio, trabecular number but increased trabecular spacing in tibia and distal radius. Finite element analysis further confirmed significantly lower stiffness and failure load in tibia. Biochemical studies also showed lower bone resorption and severely suppressed bone formation activity (P < 0.001). The unchanged total hip BMD between two groups confirmed the beneficial effects of bisphosphonate on trabecular bone, thus preventing osteoporotic fractures at large in previous studies. However, the inferior structural, densitometric and biomechanical properties at cortical bones, especially femur midshaft, need a special attention to look into the association between long-term bisphosphonate intake and the occurrence of stress fractures. When patients taking bisphosphonate complain of proximal thigh pain or discomfort, plain X-ray film can be the first line screening. All patients prescribed with bisphosphonate should be informed of such a complication though we must stress its rarity.Chinese medical journal 01/2013; 126(1):27-33. · 0.86 Impact Factor -
Article: Quantitative Ultrasound for Predicting Curve Progression in Adolescent Idiopathic Scoliosis: A Prospective Cohort Study of 294 Cases Followed-Up Beyond Skeletal Maturity.
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ABSTRACT: Adolescent idiopathic scoliosis (AIS) is prevalent among adolescents and can carry significant morbidities. We evaluated the use of quantitative ultrasound (QUS) for predicting curve progression in patients with AIS. We recruited 294 girls with AIS at a mean age of 13.4 years, and they were prospectively followed beyond skeletal maturity for curve progression. We recorded 3 calcaneal QUS measurements at baseline, namely broadband ultrasound attenuation (BUA), velocity of sound (VOS), and stiffness index (SI). Logistic regression analysis indicated that SI, age, menarchal status, and Cobb angle were significant prognostic factors to be included in the final prediction model. The adjusted odds ratio of curve progression for Z-score of SI≦0 was 2.00 (95% CI: 1.08-3.71). The area under the ROC curve was 0.831 (95% CI: 0.785-0.877). The results of this study indicate that SI was an independent and significant prognostic factor for AIS and could be considered in addition to other prognostic factors when estimating the risk for curve progression and planning treatment for patients with AIS.Ultrasound in medicine & biology 12/2012; · 2.02 Impact Factor -
Article: Abnormal bone quality in adolescent idiopathic scoliosis: a case-control study on 635 subjects and 269 normal controls with bone densitometry and quantitative ultrasound.
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ABSTRACT: A case-control study comparing bone quality in Adolescent Idiopathic Scoliosis (AIS) with normal controls. To evaluate bone quality with quantitative ultrasound (QUS) in AIS and normal controls so as to detect any derangement in bone quality among AIS subjects. AIS is characterized by complex spinal deformities. Despite its high prevalence and clinical impact in adolescents, etiology of AIS remains unknown but one possible mechanism is related to derangement of bony mechanical stability, as quantified by bone mineral density (BMD) and bone quality. AIS is known for its association with osteopenia, but little is known about the bone quality in AIS. With technological advancement, QUS can provide objective measurement of bone quality. In this study, we sought to compare bone quality in AIS with normal controls using QUS in addition to the conventional BMD measurement. Six hundred thirty-five AIS girls and 269 age-matched normal girls were investigated. Broadband ultrasound attenuation (BUA), velocity of sound (VOS), and stiffness index (SI) were measured over the nondominant calcaneus using QUS. The results were correlated with anthropometric measurement, radiologic assessment, and BMD of both hips. The z-score of BMD at the femoral neck of AIS subjects (-0.47 ± 0.97) was significantly lower than that of normal controls (-0.12 ± 1.01, P < 0.001). Crude comparison showed that BUA, VOS, and SI of AIS group were 3.8% (P < 0.01), 0.5% (P = 0.042), and 6.9% (P < 0.01) lower than controls, respectively. After controlling confounding from maturity, body weight, body height, and BMD with multiple linear regression analysis for both mild (Cobb's angle ≤ 25°) and severe (Cobb's angle > 25°) curves, BUA and SI were found to be statistically significantly lower in AIS as compared with controls (P < 0.05). In addition to higher prevalence of osteopenia, AIS patients were also found to have deranged bone quality. These might contribute to the etiopathogenesis of spinal deformities in AIS.Spine 01/2011; 36(15):1211-7. · 2.08 Impact Factor -
Article: Type IIB human skeletal muscle fibers positively correlate with bone mineral density irrespective to age.
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ABSTRACT: Age-associated decrease in type IIA/B human skeletal muscle fibers was detected in human biopsies in our previous study. The relationship between change in muscle fiber typing and bone mineral density (BMD) is, however, unknown either cross-sectionally or longitudinally. We therefore conducted a cross-sectional study to investigate their correlation using human muscle biopsies. Forty human subjects aged (53.4 ± 20.2) years were recruited. Histomorphometric parameters of their muscle biopsies were measured by ATPase staining and image analysis, including average area percentage, fiber number percentage, mean fiber area, and area percentage of connective tissues. Hip and spine BMD was measured by dual-energy X-ray absorptiometry. Partial correlation with adjusting age was performed. Type IIB muscle fiber was found positively correlated with hip BMD irrespective to age and demonstrated significantly stronger relationship with BMD among all fiber types, in terms of its cross-sectional area (r = 0.380, P = 0.029) and size (r = 0.389, P = 0.025). Type IIA muscle fibers associated with hip BMD in mean fiber area only (r = 0.420, P = 0.015). Type IIB muscle fiber may play an important role in maintaining bone quality. This may also be a relatively more sensitive fiber type of sarcopenia and osteoporosis. These findings further consolidate the muscle-bone relationship.Chinese medical journal 11/2010; 123(21):3009-14. · 0.86 Impact Factor -
Article: The association of disproportionate skeletal growth and abnormal radius dimension ratio with curve severity in adolescent idiopathic scoliosis.
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ABSTRACT: Abnormal anthropometric measurements during the peripubertal growth spurt have been documented in adolescent idiopathic scoliosis (AIS). Magnetic resonance (MR) imaging studies of the spine have suggested a disproportionate endochondral and membranous ossification in AIS. The present study aimed at investigating whether disproportional ossification and skeletal growth occurred in the peripheral bone of AIS patients using the radius as the target bone. Skeletally mature AIS girls with different severity (n = 290) and age-matched control healthy girls (n = 80) were recruited. The anthropometric parameters were recorded. The midshaft of non-dominant radius was scanned with peripheral quantitative computed tomography (pQCT) and the radius diameter was calculated from the cross-sectional area. Radius dimension ratio was derived from the ratio of radius diameter to radius length. The anthropometric parameters were compared between AIS and control with adjustment for age. The radius dimension ratio was further correlated with curve severity in AIS girls using Pearson's correlation test. The analysis showed that the arm span and radius length were slightly longer in AIS girls. The BMI of AIS girls was significantly lower than the controls. The radius dimension ratio in severe AIS girls was significantly lower than the controls and the ratio of AIS girls correlated with the curve severity (r = -0.120; p = 0.039). The abnormal radius dimension ratio supported the presence of systemic growth abnormalities in AIS. Disproportional endochondral-membranous ossification could explain for the observation. The observation of the association of radius dimension ratio with curve severity provides an important potentially clinically measurable parameter for further longitudinal studies on the prognostication of curve progression in AIS.European Spine Journal 05/2010; 19(5):726-31. · 1.97 Impact Factor -
Article: Re: Szalay EA, Bosch P, Schwend RM, et al. Adolescents with idiopathic scoliosis are not osteoporotic. Spine 2008;33:802-6.
Spine 01/2010; 35(1):130; author reply 130-1. · 2.08 Impact Factor -
Article: A relook into the association of the estrogen receptor [alpha] gene (PvuII, XbaI) and adolescent idiopathic scoliosis: a study of 540 Chinese cases.
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ABSTRACT: A genetic association study of estrogen receptor-[alpha] gene (ESR1) with adolescent idiopathic scoliosis (AIS) in Chinese. To investigate whether: 1) PvuII and XbaI polymorphisms in ESR1 are predisposition factor for AIS and 2) these polymorphisms correlate with the severity of curvature in AIS. A common single nucleotide polymorphism (SNP) in ESR1 (XbaI) was found to be associated with curve severity in Japanese AIS patients recently. The role of ESR1 as a predisposition gene using a case-control design in other ethnic groups is required to confirm the previous associations. A total of 540 Chinese AIS girls with Cobb angle above 20 degrees were recruited as cases together with 260 healthy controls. The effect of ESR1 SNPs on severity of scoliosis was analyzed in a subgroup of AIS patients (n = 364) followed up until skeletal maturity with the maximum Cobb angle recorded. Two SNPs in ESR1 were genotyped by PCR-restriction fragment length polymorphism in all subjects. The allelic frequency of X allele was 23% in both case and control groups. The P allele was found at allelic frequency of 40% and 36% in the case and control groups, respectively. No association between the two ESR1 SNPs and the occurrence of AIS by both genotype and haplotype analysis could be established, suggesting that both SNPs were not predisposition alleles for AIS. AIS patients with different genotypes showed no difference in the maximum Cobb angle. No association was found between the genotype and anthropometric measurements in AIS patients. The previously reported association with curve severity could not be replicated in our large series of Chinese AIS patients. The current study also did not show any association of the 2 SNPs with increased risk of having AIS.Spine 11/2006; 31(21):2463-8. · 2.08 Impact Factor -
Article: A Relook Into the Association of the Estrogen Receptor α Gene (PvuII, XbaI) and Adolescent Idiopathic Scoliosis: A Study of 540 Chinese Cases
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ABSTRACT: Study Design. A genetic association study of estrogen receptor-α gene (ESR1) with adolescent idiopathic scoliosis (AIS) in Chinese. Objectives. To investigate whether: 1) PvuII and XbaI polymorphisms in ESR1 are predisposition factor for AIS and 2) these polymorphisms correlate with the severity of curvature in AIS. Summary of Background Data. A common single nucleotide polymorphism (SNP) in ESR1 (XbaI) was found to be associated with curve severity in Japanese AIS patients recently. The role of ESR1 as a predisposition gene using a case-control design in other ethnic groups is required to confirm the previous associations. Methods. A total of 540 Chinese AIS girls with Cobb angle above 20° were recruited as cases together with 260 healthy controls. The effect of ESR1 SNPs on severity of scoliosis was analyzed in a subgroup of AIS patients (n = 364) followed up until skeletal maturity with the maximum Cobb angle recorded. Two SNPs in ESR1 were genotyped by PCR-restriction fragment length polymorphism in all subjects. Results. The allelic frequency of X allele was 23% in both case and control groups. The P allele was found at allelic frequency of 40% and 36% in the case and control groups, respectively. No association between the two ESR1 SNPs and the occurrence of AIS by both genotype and haplotype analysis could be established, suggesting that both SNPs were not predisposition alleles for AIS. AIS patients with different genotypes showed no difference in the maximum Cobb angle. No association was found between the genotype and anthropometric measurements in AIS patients. Conclusion. The previously reported association with curve severity could not be replicated in our large series of Chinese AIS patients. The current study also did not show any association of the 2 SNPs with increased risk of having AIS.Spine 09/2006; 31(21):2463-2468. · 2.08 Impact Factor -
Article: Correlations of calcaneal QUS with pQCT measurements at distal tibia and non-weight-bearing distal radius.
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ABSTRACT: Quantitative ultrasound (QUS) is used for prediction for risks of osteoporotic fractures at various skeletal sites, irrespective of weight-bearing or non-weight-bearing skeletons. In the current study, we investigated the correlation between calcaneal QUS measurements (BUA, VOS, and Soundness) and volumetric trabecular, cortical, and its integral bone mineral density (tBMD, cBMD, and iBMD) using peripheral quantitative computed tomography (pQCT) of the weight-bearing distal tibia and non-weight-bearing distal radius in 198 healthy Chinese women between 40 and 62 years of age. Results showed that BUA, VOS, and Soundness measured by calcaneal QUS were significantly correlated with tBMD, cBMD, and iBMD of both distal tibia and distal radius (r = 0.210-0.447; all P < 0.01). The correlation coefficients of all the individual parameters between calcaneus and distal tibia were correspondingly higher (r = 0.214-0.447; all P < 0.01) than that of distal radius (r = 0.210-0.368; all P < 0.01). QUS Soundness showed the highest correlation (r = 0.447; P < 0.01) with tBMD of distal tibia when comparing with all other parameters between these two measurement devices. Stronger "within-device" correlations (r = 0.640-0.764; all P < 0.01) were found in pQCT measurements between distal tibia and radius. In addition, the largest and significant age-related decline was found in tBMD of the distal radius measured by pQCT and Soundness of the QUS measurement in the postmenopausal group. In conclusion, heel QUS measurement demonstrated slightly better correlation with trabecular bone of the weight-bearing skeleton than that of the non-weight-bearing skeleton measured by pQCT.Journal of Bone and Mineral Metabolism 01/2004; 22(5):486-90. · 2.27 Impact Factor -
Article: Trabecular bone status in ultradistal tibia under habitual gait loading: a pQCT study in postmenopausal women.
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ABSTRACT: This study investigated regional volumetric trabecular bone mineral density (tBMD) and bone area at the ultradistal tibia in Chinese women using peripheral quantitative computed tomography. Fifty-six postmenopausal women aged 47-62 yr participated in BMD measurements at baseline and 22 of them were followed at both 1-yr and 3-yr follow-up scans. Regional baseline tBMD, rate of annual bone loss, and trabecular bone area were determined. Baseline measurements showed that the tBMD of both the posterior (252.9+/-63.4 mg/cm(3)) and medial (226.6+/-68.9 mg/cm(3)) regions was significantly higher than that of the anterior (126.3+/-61.9 mg/cm(3)) and lateral regions (149.8+/-50.6 mg/cm(3)), respectively (p<0.001). Both the 1-yr and 3-yr follow-up measurements showed that there was significant physiological annual tBMD loss on an average of 1.61%, at the four regions. Inter-slice regional tBMD and trabecular bone area measurements demonstrated a significant linear decrease from the distal to proximal aspects (p<0.001). Findings suggest that dynamic compressive loading during the heel strike and the body weight vector shifting toward the medial aspect during the stance phase in a normal gait might account for the regional tBMD differences. Increased tBMD and bone area toward the distal tibial endplate may adapt to withstand the axial impact loading. However, the low-impact weight-bearing nature of a normal gait may not be osteogenic to prevent regional bone loss. An exercise program specific to the women at risk should be contemplated.Journal of Clinical Densitometry 9(2):175-83. · 1.29 Impact Factor
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Institutions
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2004–2012
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The Chinese University of Hong Kong
- • Department of Orthopaedics and Traumatology
- • Department of Chemical Pathology
Hong Kong, Hong Kong
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