Gender differences in the ratio between humerus width and length are established prior to puberty

Hormonal Control of Bone Architecture Throughout the Lifespan: Implications for Fracture Prediction and Prevention

BACKGROUND

Skeletal modeling in childhood and adolescence and continuous remodeling throughout the lifespan are designed to adapt to a changing environment and resist external forces and fractures. The flux of sex steroids in men and women, beginning from fetal development and evolving through infancy, childhood, puberty, young adulthood, peri/menopause transition, and postmenopause, is critical for bone size, peak bone mass, and fracture resistance.

OBJECTIVE

This review will highlight how changes in sex steroids throughout the lifespan affect bone cells and the consequence of these changes on bone architecture and strength.

METHODS

Literature review and discussion.

RESULTS

The contributions of estrogen and testosterone on skeletal development have been difficult to study due to the reciprocal and intertwining contributions of one on the other. Although orchiectomy in men renders circulating testosterone absent, circulating estrogen also declines due to testosterone being the substrate for estradiol. The discovery of men with absent estradiol or resistance to estrogen and the study of mouse models led to the understanding that estrogen has a larger direct role in skeletal development and maintenance in men and women. The mechanistic reason for larger bone size in men is incompletely understood but related to indirect effects of testosterone on the skeleton, such as higher muscle mass leading to larger mechanical loading. Declines in sex steroids during menopause in women and androgen deprivation therapies in men have profound and negative effects on the skeleton. Therapies to prevent such bone loss are available, but how such therapies can be tailored based on bone size and architecture remains an area of investigation.

CONCLUSION

In this review, the elegant interplay and contribution of sex steroids on bone architecture in men and women throughout the lifespan is described.

The use of the pediatric physeal slide-traction plate in the treatment of neer–horwitz grade IV proximal humeral fractures in children: A case report and literature review

Background

Proximal humeral fractures (PHFs) are rare in children. Currently, the recommended surgical methods for severely displaced PHFs are closed reduction and percutaneous fixation using K-wires or intramedullary nailing, which can't provide firm internal fixation, especially for older and high-weight children. This study aimed to introduce a novel surgical approach, pediatric physeal slide-traction plate fixation (PPSP), for Neer–Horwitz grade IV PHFs in children.

Case summary

A 9-year-old boy presented with left shoulder pain and swelling due to a car accident. Physical examination revealed a positive shoulder deformity and local tenderness. On physical examination, we palpated bone friction without vascular and nerve damage. Based on imaging findings, we diagnosed Neer-Horwitz grade IV PHF. In view of the patient's condition, we performed PPSP after careful communication with the patient's parents. After 22 months of follow-up, the patient's left shoulder function was satisfactory, and there was no restriction of activities.

Conclusion

According to previous studies, PPSP is only used for femur fractures. To the best of our knowledge, this is the first in the treatment for PHFs. Given the satisfactory outcomes, it is a safe and effective method and may provide a reference to cure analogous patients in the future.

Growth to early adulthood following extremely preterm birth: the EPICure study

OBJECTIVE

To investigate growth trajectories from age 2.5 to 19 years in individuals born before 26 weeks of gestation (extremely preterm; EP) compared with term-born controls.

METHODS

Multilevel modelling of growth data from the EPICure study, a prospective 1995 birth cohort of 315 EP participants born in the UK and Ireland and 160 term-born controls recruited at school age. Height, weight, head circumference and body mass index (BMI) z-scores were derived from UK standards at ages 2.5, 6, 11 and 19 years.

RESULTS

129 (42%) EP children were assessed at 19 years. EP individuals were on average 4.0 cm shorter and 6.8 kg lighter with a 1.5 cm smaller head circumference relative to controls at 19 years. Relative to controls, EP participants grew faster in weight by 0.06 SD per year (95% CI 0.05 to 0.07), in head circumference by 0.04 SD (95% CI 0.03 to 0.05), but with no catch-up in height. For the EP group, because of weight catch-up between 6 and 19 years, BMI was significantly elevated at 19 years to +0.32 SD; 23.4% had BMI >25 kg/m² and 6.3% >30 kg/m² but these proportions were similar to those in control subjects. EP and control participants showed similar pubertal development in early adolescence, which was not associated with height at 19 years in either study group. Growth through childhood was related to birth characteristics and to neonatal feeding practices.

CONCLUSIONS

EP participants remained shorter and lighter and had smaller head circumferences than reference data or controls in adulthood but had elevated BMI.

Epidemiological Analysis of Displaced Supracondylar Fractures

INTRODUCTION

 Supracondylar fractures are one of the most common fracture patterns sustained by children, and one of the most common injuries requiring operative fixation. Understanding the complications associated with supracondylar fractures is vital for the practicing orthopedic surgeon. This analysis of supracondylar fractures examined the clinically important aspects including vascular injury, compartment syndrome, neurological injury, brachialis entrapment, associated injuries, and etiologies of injury. Recent advances in technology have resulted in a myriad of new forms of recreational equipment for children to play with. The purpose of this study is to compare the historical literature, the current literature, and a single surgeon's sample of supracondylar fractures. In addition, this study aims to evaluate if any changes in epidemiology or etiology have occurred due to the development of new recreational equipment.

OBJECTIVE

 The purpose of this study is to evaluate and provide a qualitative overview of the epidemiology of displaced supracondylar fractures, to compare historically reported numbers to more recent literature as well as a single surgeon sample, and to evaluate if changes in epidemiology or etiology have occurred due to the new recreational equipment that children use.

METHODS

Some 75 displaced supracondylar elbow fractures were reviewed. Data elements recorded from the electronic medical record (EMR) included patient age, gender, height, weight, handedness, date, time, location, mechanism, Gartland classification, concurrent injuries, and neurovascular status.  Results: In this study, there were 42 males and 33 females. The average age was six years. Some 70 of the 75 patients were older than the age three. One fracture was open, nine fractures had a pucker sign, seven presented with a nerve palsy, four presented without a pulse, and seven patients presented with an additional ipsilateral distal radius fracture. All fractures were the result of a fall. Falls from playground equipment resulted in 29 fractures. There were 10 from falls off of furniture, six from falls during sports, three from falls on the stairs, and three from fall off of bikes. The remaining fractures resulted from running, tripping, falling from a toy ball, sled, tree, wagon, fence, bounce house, van, deck, power wheels car, ATV, and a go-cart. Some 64 fractures were transferred from 27 different outside hospitals. Eleven fractures presented directly to the ED. Twenty-six fractures occurred during the summer, 20 occurred in the autumn, 6 occurred in the winter, and 23 occurred during the spring. Some 35 fractures occurred at home, 30 on the school grounds, four in a gymnasium, four in a park, one at a farm show, and one in a parking lot. Some 25 fractures were treated between midnight and 8 am, 16 were treated between 8 am and 5 pm, and 34 were treated between 5 pm and midnight.  Conclusion: Pediatric supracondylar fractures are common in children, and many of them require operative intervention. This study examined the most important aspects of supracondylar fractures. This update provides a look at the clinically important aspects of supracondylar fractures and compares them to previous teachings and canon. Despite the advancement and changes in recreational equipment that children are using, children are still sustaining supracondylar fractures in the most common ways including falls from playground equipment and falls from standing.

Stature estimation equations for South Asian skeletons based on DXA scans of contemporary adults

OBJECTIVES

Stature estimation from the skeleton is a classic anthropological problem, and recent years have seen the proliferation of population-specific regression equations. Many rely on the anatomical reconstruction of stature from archaeological skeletons to derive regression equations based on long bone lengths, but this requires a collection with very good preservation. In some regions, for example, South Asia, typical environmental conditions preclude the sufficient preservation of skeletal remains. Large-scale epidemiological studies that include medical imaging of the skeleton by techniques such as dual-energy X-ray absorptiometry (DXA) offer new potential datasets for developing such equations.

MATERIALS AND METHODS

We derived estimation equations based on known height and bone lengths measured from DXA scans from the Andhra Pradesh Children and Parents Study (Hyderabad, India). Given debates on the most appropriate regression model to use, multiple methods were compared, and the performance of the equations was tested on a published skeletal dataset of individuals with known stature.

RESULTS

The equations have standard errors of estimates and prediction errors similar to those derived using anatomical reconstruction or from cadaveric datasets. As measured by the number of significant differences between true and estimated stature, and the prediction errors, the new equations perform as well as, and generally better than, published equations commonly used on South Asian skeletons or based on Indian cadaveric datasets.

CONCLUSIONS

This study demonstrates the utility of DXA scans as a data source for developing stature estimation equations and offer a new set of equations for use with South Asian datasets.

Distinct Proximal Humeral Geometry in Chinese Population and Clinical Relevance

BACKGROUND

Replicating humeral anatomy during shoulder arthroplasty is important for good patient outcomes. The proximal humeral geometry of the Chinese population has been rarely reported. We analyzed the geometry of the proximal part of the humerus in Chinese subjects and compared it with that of Western populations and the dimensions of available prostheses.

METHODS

Eighty healthy Chinese subjects underwent computed tomography (CT)-arthrography. Three-dimensional (3D) digital humeral and glenoid models were reconstructed, and geometric parameters were measured. Humeral measurements included the radius of curvature, articular surface diameter and thickness, anterior-posterior/superior-inferior (AP/SI) articular surface diameter ratio, articular surface thickness/radius of curvature ratio, surface arc, inclination angle, retroversion angle, and medial and posterior offsets. Glenoid measurements included SI length, AP length, SI radius, and AP radius.

RESULTS

The average radius of curvature (and standard deviation) of the humeral head was 22.1 ± 1.9 mm, the articular surface diameter averaged 42.9 ± 3.6 mm, and the articular surface thickness averaged 16.9 ± 1.5 mm. There was strong linear correlation between the articular surface diameter and thickness (r = 0.696, p = 0.001), with a linear regression relationship of thickness = 0.357 × diameter + 1.615. The AP/SI articular surface diameter ratio averaged 0.93 ± 0.03; the articular surface thickness/radius of curvature ratio, 0.77 ± 0.05; the surface arc, 153° ± 5.6°; the inclination angle, 133° ± 3.1°; and the retroversion angle, 22.6° ± 10.2°. The medial and posterior offsets averaged 6.3 ± 0.9 mm and 0.4 ± 0.78 mm, respectively; the SI and AP lengths, 30.15 ± 3.70 mm and 20.35 ± 2.56 mm; and the SI and AP radii, 23.49 ± 2.48 mm and 25.54 ± 3.07 mm. Compared with the Western population, the Chinese cohort had a smaller radius of curvature (p < 0.001), smaller articular surface diameter (p = 0.009), larger articular surface thickness/radius of curvature ratio (p < 0.001), larger surface arc (p < 0.001), smaller inclination angle (p < 0.001), and smaller posterior offset (p < 0.001). Unlike the Western population, the Chinese population had higher glenohumeral conformity in the coronal plane than in the axial plane. Many manufacturers' shoulder prostheses do not adequately cover the range of humeral head dimensions in our Chinese cohort.

CONCLUSIONS

The geometric parameters of the humeri in the Chinese population differ from those in other populations. These differences have clinical relevance with regard to implant design and arthroplasty technique and likely affect clinical outcomes.

Multigenerational impact of maternal overnutrition/obesity in the sheep on the neonatal leptin surge in granddaughters

BACKGROUND/OBJECTIVES

We have reported that maternal overnutrition/obesity (OB) in sheep resulting from feeding 150% of National Research Council (NRC) requirements throughout gestation leads to maternal hyperglycemia and hyperinsulinemia. Further, newborn lambs born to OB vs control-fed (CON, 100% of NRC) ewes exhibited greater adiposity, increased blood cortisol, insulin and glucose and the elimination of the postnatal leptin spike seen in lambs born to CON ewes. This early postnatal leptin peak is necessary for the development of hypothalamic circuits, which program appetite in later life. This study evaluated the multigenerational impact of OB on insulin:glucose dynamics of mature female F1 offspring fed only to requirements throughout gestation and on their lambs (F2 generation).

DESIGN AND METHODS

Adult F1 female offspring born to OB (n=10) or CON (n=7) ewes were utilized. All F1 ewes were subjected to a glucose tolerance test at midgestation and late gestation. Jugular blood was obtained from F2 lambs at birth (day 1) through postnatal day 11, and plasma glucose, insulin, cortisol and leptin concentrations were determined. Dual-energy X-ray absorptiometry was utilized to determine bone mineral density, bone mineral content, lean tissue mass and fat tissue mass.

RESULTS

Fasted blood glucose and insulin concentrations were greater (P<0.05) in OBF1 than CONF1 ewes at midgestation and late gestation. Further, after glucose infusion, both glucose and insulin concentrations remained higher in OBF1 ewes (P<0.05) than CONF1 ewes, demonstrating greater insulin resistance. Blood concentrations of glucose, insulin and cortisol and adiposity were higher (P<0.01) in OBF2 lambs than CONF2 lambs at birth. Importantly, OBF2 lambs failed to exhibit the early postnatal leptin peak exhibited by CONF2 lambs.

CONCLUSIONS

These data suggest that these OBF2 lambs are predisposed to exhibit the same metabolic alterations as their mothers, suggesting a multigenerational programming effect.

Association between components of body composition and scoliosis: a prospective cohort study reporting differences identifiable before the onset of scoliosis

There is an increasing body of research suggesting that low body weight is associated with scoliosis, but this is based on case-control studies, which are prone to bias. No studies have investigated the components of body weight: fat and lean mass. We have therefore carried out the first population-based prospective study of the association between fat and lean mass at age 10 years assessed by dual-energy X-ray absorptiometry (DXA), with presence of scoliosis at age 15 years using the Avon Longitudinal Study of Parents and Children (ALSPAC). All children with scoliosis at age 10 years were excluded. Of 5299 children at age 15 years, 312 (5.9%) had scoliosis. Our results show a negative association between body mass index (BMI)/body weight at age 10 years and scoliosis at age 15 years, with a 20% reduced risk of scoliosis per SD increase in BMI (odds ratio [OR], 0.80; 95% confidence interval [CI], 0.70-0.92; p = 0.001). This association with BMI/body weight reflects associations with both fat mass and lean mass. After adjustment for age, gender, leg length, and fat mass per SD increase in lean mass, there was a 20% reduced risk of scoliosis (OR, 0.80; 95% CI, 0.65-0.97) and per SD increase in fat mass there was a 13% reduced risk of scoliosis (OR, 0.87; 95% CI, 0.74-1.03). In terms of adipocyte function, an inverse association was seen between leptin at age 10 years and scoliosis (OR for scoliosis per SD increase in leptin of 0.78; 95% CI, 0.63-0.99), and a positive association between adiponectin at age 10 years and scoliosis (OR for scoliosis per SD increase in adiponectin of 1.44; 95% CI, 0.99-2.10). This is the first study to address the association between the individual components of body weight and scoliosis in a prospective cohort study, and shows altered body composition that is present before the onset of clinically detected scoliosis.

Prevention of Osteoporosis and Bone Fragility

The importance of optimal bone growth in childhood and adolescence has been recognized as one of the key strategies in osteoporotic fracture prevention. Low birth size, poor childhood growth, and low peak bone mass at the cessation of growth have been linked to the later risk of osteoporosis and hip fracture. Formerly, the focus was merely on maximizing bone mineral accrual because a high peak bone mineral mass may prevent attainment of a critical “fracture threshold” associated with age-related bone loss and osteoporosis. More recently, the focus has shifted away from bone mineral accrual—as measured by dual-energy X-ray absorptiometry (DXA)—toward the optimization of bone strength. This is partly because of the advances in bone imaging that have enabled estimation of bone strength beyond bone mass. In this review, we briefly describe long-bone growth and structural development and our abilities to assess bone properties by medical imaging tools. In addition, we summarize the evidence of factors contributing to skeletal growth, bone fragility, and the development of strong, healthy bones.

Investigation of sex differences in hip structure in peripubertal children

CONTEXT

There is evidence that sex differences in hip structure are increased during puberty, possibly as a consequence of associated changes in body composition.

OBJECTIVES

The objective of the study was to explore relationships between sex, puberty, hip structure, and body composition.

DESIGN/SETTING

The design was a longitudinal birth cohort study: The Avon Longitudinal Study of Parents and Children.

PARTICIPANTS

Participants included 3914 boys and girls (mean age 13.8 yr).

OUTCOME MEASURES

Measures included dual-energy x-ray absorptiometry-derived femoral neck width (FNW), cortical thickness (CT), bending strength [cross-sectional moment of inertia (CSMI)], section modulus, buckling ratio (BR), and femoral neck and total hip bone mineral density.

RESULTS

FNW, CT, and CSMI were higher in boys, whereas BR was lower in girls (P<0.001). Differences in hip structure were studied according to puberty (self-completion Tanner stage questionnaires). FNW, CT, and CSMI were higher in Tanner stage IV/V vs. I/II, particularly in boys (P<0.001, puberty-sex interaction). BR was lower in Tanner stage IV/V, particularly in girls (P=0.008, puberty-sex interaction). Adjusting for height, fat mass, and lean mass resulted in differential attenuation in the sexes, such that CT attenuated by about 80% and about 40% in boys and girls, respectively (P=0.004, puberty-sex interaction for adjusted CT, Tanner stages I/II vs. IV/V). The difference in BR showed little attenuation after adjustment.

CONCLUSION

During puberty, hip-bending strength increases, particularly in boys, due to their greater FNW, reflecting changes in height, fat mass, and lean mass. In contrast, BR falls during puberty, particularly in girls, reflecting their smaller FNW relative to CT, involving mechanisms partly independent of height and body composition.

The association of disproportionate skeletal growth and abnormal radius dimension ratio with curve severity in adolescent idiopathic scoliosis

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.

The age of puberty determines sexual dimorphism in bone structure: a male/female co-twin control study

BACKGROUND

Taller stature and larger bone size in males are attributed to more rapid growth than in females. However, comparing sexes of the same age mismatches by pubertal stage, so males will be less mature than females. Comparing sexes of the same pubertal stage mismatches by age, so males will be older than females.

OBJECTIVE

We hypothesized that sex differences in stature and bone structure are the result of sex differences in the duration but not the rate of prepubertal and pubertal growth.

METHODS

We measured bone dimensions in 90 male/female co-twin pairs aged 7-18 yr using anthropometry and dual x-ray absorptiometry. Forty-two pairs had follow-up assessments. Within-pair differences were expressed as a percentage of the pair mean.

RESULTS

Thirty percent of the 1-1.5 sd sex difference in bone widths and midfemur bending strength observed in 11 postpubertal pairs was present in 43 prepubertal pairs. In prepubertal pairs, annual growth in leg length was about 1.5 times truncal growth, but neither rate differed by sex. During puberty, truncal growth in both sexes was higher than before puberty but did not differ by sex. The longer period of pre- and intrapubertal growth in males produced most of the sex difference in bone morphology observed in postpubertal twins.

CONCLUSION

Sex differences in bone morphology are the result of the later onset of puberty in males, not more rapid growth. Differences in bone widths are partly established before puberty.

Skeletal growth and peak bone strength

Bone size, shape and internal architecture, and not just bone mass, account for differences in bone strength between individuals, sexes and races. The differences in bone morphology in old age - whether an individual's bone size and mass occupy the 5th, 50th or 95th percentile - is determined early in life. Bone traits track from the position established early in life. Genetic and environmental factors establish the morphological features of bone through the cellular machinery of bone modelling and remodelling which adapts bone to its loading circumstance by modifying its size and shape and the distribution of its mass. The need for both strength for loading and lightness for mobility are achieved by deposition of bone where it is needed and removal of bone from where it is not. The machinery has enormous capacity during growth, as can be seen in the bone structure of the elite athlete, but not during advancing age because of changes in the cellular machinery itself and in systemic hormonal regulatory factors.

Bone fragility contributes to the risk of fracture in children, even after moderate and severe trauma

We prospectively examined whether the relationship between skeletal fragility and fracture risk in children 9.9 +/- 0.3 (SD) yr is affected by trauma level. Bone size relative to body size and humeral vBMD showed similar inverse relationships with fracture risk, irrespective of whether fractures followed slight or moderate/severe trauma.

INTRODUCTION

Fracture risk in childhood is related to underlying skeletal fragility. However, whether this relationship is confined to low-trauma fractures or whether skeletal fragility also contributes to the risk of fracture caused by higher levels of trauma is currently unknown.

MATERIALS AND METHODS

Total body DXA scan results obtained at 9.9 yr of age were linked to reported fractures over the following 2 yr in children from the Avon Longitudinal Study of Parents and Children. DXA scan results that were subsequently derived included total body less head (TBLH) bone size relative to body size (calculated from TBLH area adjusted for height and weight) and humeral volumetric BMD (vBMD; derived from subregional analysis at this site). Trauma level was assigned using the Landin classification based on a questionnaire asking about precipitating causes.

RESULTS

Of the 6204 children with available data, 549 (8.9%) reported at least one fracture over the follow-up period, and trauma level was assigned in 280 as follows: slight trauma, 56.1%; moderate trauma, 41.0%; severe trauma, 2.9%. Compared with children without fractures, after adjustment for age, sex, socioeconomic status, and ethnicity, children with fractures from both slight and moderate/severe trauma had a reduced bone size relative to body size (1133 cm(2) in nonfractured children versus 1112 cm(2) for slight trauma fractures, p < 0.001; 1112 cm(2) for moderate/severe trauma fractures, p = 0.001) and reduced humeral vBMD (0.494 g/cm(3) in nonfractured children versus 0.484 g/cm(3) for slight trauma fractures, p = 0.036; and 0.482 g/cm(3) for moderate/severe trauma fractures, p = 0.016).

CONCLUSIONS

Skeletal fragility contributes to fracture risk in children, not only in fractures caused by slight trauma but also in those that result from moderate or severe trauma.