External fixator versus elastic stable intramedullary nail for treatment of metaphyseal-diaphyseal junction fractures of the pediatric distal femur: a case-control study.

BACKGROUND: Several methods have been used for the treatment of pediatric distal femoral fractures, such as elastic stable intramedullary nail (ESIN), external fixator (EF) and plate osteosynthesis, but there has been no consensus about the optimal method. The purpose of this study was to compare the clinical outcome between EF and ESIN techniques used in metaphyseal-diaphyseal junction (MDJ) fractures of the pediatric distal femur. METHODS: We retrospectively analyzed operatively treated MDJ fractures of pediatric distal femur between January 2015 and January 2022. Patient charts were reviewed for demographics, injury and data of radiography. All of the patients were divided into EF and ESIN groups according to the operation techniques. Malalignment was defined as more than 5 degrees of angular deformity in either plane. Clinical outcomes were measured by Flynn scoring system. RESULTS: Thirty-eight patients were included in this study, among which, 23 were treated with EF, and 15 with ESIN. The mean follow-up time was 18 months (12-24 months). At the final follow-up, all of the fractures were healed. Although there were no statistical differences between the two groups in demographic data, length of stay, estimated blood loss (EBL), rate of open reduction, time to fracture healing and Flynn score, the EF was superior to ESIN in operative time, fluoroscopic exposure and time to partial weight-bearing. The EF group had a significantly higher rate of skin irritation, while the ESIN had a significantly higher rate of malalignment. CONCLUSION: EF and ESIN are both effective methods in the treatment of MDJ fractures of the pediatric distal femur. ESIN is associated with lower rates of skin irritation. However, EF technique has the advantages of shorter operative time, reduced fluoroscopic exposure, and shorter time to partial weight-bearing, as well as lower incidence of malalignment. LEVEL OF EVIDENCE: Level III.

Metaphyseal and Diaphyseal Contours: Variants and Pitfalls.

We discuss several variants of the metaphyseal and diaphyseal bone surfaces that may be misleading in clinical practice. They include metaphyseal stripes, spiculated metaphyseal cortex, cortical desmoid, laminated lateral supracondylar ridge, cortical vascular canals, variations in shape or lucency of normal tuberosities, cortical thickening of normal ridges, and well-organized undulated hyperostosis at the proximal phalanges.

Precision shaping of elastic stable intramedullary nail for the treatment of metaphyseal diaphysis junction fracture of the distal radius in children: a preliminary report in two centers.

BACKGROUND: This study introduces a novel retrograde precision shaping elastic stable intramedullary nailing (ESIN-RPS) technique and reports clinical outcomes in pediatric distal radius metaphyseal diaphysis junction (DRMDJ) fracture. METHODS: Data about DRMDJs were collected from February 1, 2020, to April 31, 2022 at two hospitals, retrospectively. All patients were treated with closed reduction and ESIN-RPS fixation. The operation time, blood loss, fluoroscopy times, alignment, and residual angulation on X-ray were recorded. At the last follow-up, the function of wrist and forearm rotation were evaluated. RESULTS: Totally, 23 patients were recruited. The mean time of follow-up was 11 months and the minimum was 6 months. The mean operation time was 52 min, and the mean fluoroscopies pulses were 6 times. The postoperative anterioposterior (AP) alignment was 93 ± 4% and the lateral alignment was 95 ± 3%. The postoperative AP angulation was (4 ± 1)°, and the lateral angulation was (3 ± 1)°. At the last follow-up, the evaluation of the Gartland and Werley demerit criteria of wrist revealed 22 excellent cases and 1 good case. The forearm rotation and thumb dorsiflexion functions were not limited. CONCLUSION: The ESIN-RPS is a novel, safe, and effective method for the treatment of pediatric DRMDJ fracture.

Fracture edge features of diaphyseal clavicular fractures: a morphologic study.

BACKGROUND: Previous researchers used transverse fractures centered over the midpoint of the clavicle as the diaphyseal clavicular fracture models. However, as a result of shear stress concentration in sigmoid-shaped structures, most diaphyseal clavicular fractures have coronal fracture edges and are located distal to the midpoint. The purpose of this study was to quantify the morphology and utilize these parameters to establish clinically relevant fracture models. METHODS: The computed tomographic DICOM data of 100 consecutive patients were included. We investigated the morphologic characteristics of the fracture edges after virtual fracture reduction. The fracture orientation was determined based on the normal vectors of the best-fit plane of the fracture edges. The fracture location was measured by the extreme points of the edges. The fracture configuration was evaluated using fracture maps. RESULTS: There were 28 simple, 43 wedge, and 29 multifragmentary types. Coronal oriented fracture edges accounted for more than 70% of the simple, wedge, and multifragmentary types. The most proximal point of the proximal edge was located at 46.7% (42.0%-56.5%), 47.6% (42.5%-50.1%), and 46.3% (42.0%-49.3%) of the endpoint line in the simple, wedge, and multifragmentary types, respectively (P = .548). The most distal point of the distal edge was located at 72.2% (68.4%-75.0%), 73.2% (69.5%-76.9%), and 74.0% (69.6%-77.1%) of the endpoint line (P = .353). The longest proximal main fragments occurred in the simple types at 71.9% (66.3%-75.4%) of the endpoint line (P < .001), and the shortest distal main fragments occurred in the multifragmentary types at 55.8% (49.8%-59.3%) of the endpoint line (P = .001). The heatmaps showed a high concentration of anteriorly distributed wedge fragments (88%; n = 38/43) and coronally distributed multifragmentary fragments (62%; n = 18/29). CONCLUSIONS: We showed that typical diaphyseal clavicular fractures have coronal fracture edges and are located within the distal half of the diaphyseal segment. The fractured fragments were initiated anteriorly in the wedge types and then propagated coronally in the multifragmentary types. The features of these fracture edges could be useful in designing osteotomy models and provide different perspectives of anterior and superior plating techniques.

Periosteal reaction-like lesions at the cranial aspect of the humeral diaphysis have a high prevalence in older, large breed dogs and may represent entheses of the superficial pectoral muscles.

Authors have commonly observed lamellar periosteal new bone formation at the cranial aspect of the humeral diaphysis in mediolateral radiographs of the humerus for large breed dogs with no evidence of pain or lameness. The aim of this retrospective, analytical study was to investigate the appearance and prevalence of "humeral periosteal reaction-like lesions" (HPRLL) in dogs and identify any predispositions. Mediolateral radiographs of humeri were evaluated and the presence and extent of "humeral periosteal reaction-like lesions" at the cranial aspect of the humerus were recorded. Macroscopic and histological examination of the humeri were performed for one dog with HPRLL. A total of 2877 mediolateral radiographs of 1727 dogs were included and focal or extended periosteal reaction-like lesions were found in 643 humeri of 387 dogs. Body weight ≥ 30 kg and age ≥ 7 years had a statistically significant, positive effect (P < 0.001) on the presence of HPRLL. German Shepherd dogs and Rottweilers were overrepresented in the group with HPRLL (P < 0.01). At the level of the HPRLL, the enthesis of the superficial pectoral muscles (M. pectoralis descendens and M. pectoralis transversus) to the Crista tuberculi majoris and Crista humeri were macroscopically and histologically identified. The authors propose that higher mechanical loads to the enthesis in large breed dogs may lead to physiological, age-related remodeling processes of the muscular attachment. The finding should not be confused with a pathological condition such as bone neoplasia.

Ulnar diaphyseal stress injuries: a case series.

AIM: To describe the demographics, clinical context, imaging findings, and management of a case series of ulnar diaphyseal stress injuries (UDSIs) and propose a unifying mechanism for these injuries based on the imaging findings. MATERIALS AND METHODS: Seven patients from University of Florida College of Medicine (seven total injuries; mean age: 19 ± 4.4 years; three females, four males) with available clinic and imaging data and without predisposing comorbidities were included in this retrospective study. The age, gender, laterality of injury with respect to the dominant hand, attributed inciting activity, imaging method, presence and location of stress injury findings, as well as the subsequent management were analysed. RESULTS: All patients were in the second or third decade of life and there was a slight male predominance to the case series (57%). All UDSIs in this series were unilateral. Fifty-seven percent of injuries involved the dominant ulna and all involved the ulnar diaphysis along the proximal-mid junction, mid diaphysis or mid-distal junction. All injuries involved portion of the ulnar origin of the flexor digitorum profundus (FDP). All patients were managed conservatively. CONCLUSION: UDSIs are uncommon and associated with a broad range of occupational or sports-related activities. All cases in this series involved the ulnar origin of the FDP suggesting an important role for the forces exerted by this muscular attachment on the underlying bone with regard to the development of UDSIs.

Retrospective clinical outcomes in the definitive treatment of high-energy tibial diaphyseal fractures using hexapod external fixator versus monolateral external fixator.

BACKGROUND: External fixation, which can preserve the biomechanical microenvironment of fracture healing, plays an important role in managing the high-energy fractures with poor surrounding soft tissues. The purpose of this study was to determine the differences of clinical outcomes, if any, between hexapod external fixator and monolateral external fixator in the definitive treatment of high-energy tibial diaphyseal fractures. METHODS: A total of 53 patients with high-energy tibial diaphyseal fractures and definitively treated by the hexapod external fixator (HEF) or monolateral external fixator (MEF) were retrospectively collected and analyzed, from March 2015 to June 2019. There were 31 patients in the HEF treatment, and the other 22 patients were managed by the MEF. The demographic data, surgical duration, external fixation time, final radiological results, complications, and clinical outcomes were documented and analyzed. Difficulties that occurred during the treatment were classified according to Paley. The clinical outcomes were evaluated by the Association for the Study and Application of the Method of Ilizarov criteria (ASAMI) at the last clinical visit. RESULTS: The mean surgical duration in the HEF group (62.4 ± 8.3 min) was shorter than that in the MEF group (91.4 ± 6.9 min) (P < 0.05). All patients acquired complete bone union finally. Patients in the HEF group (24.2 ± 3.1 weeks) underwent a shorter average external fixation time than that in the MEF group (26.3 ± 3.8 weeks) (P < 0.05). Satisfactory alignment was achieved in all patients without the need for remanipulation. The residual sagittal plane deformities in the HEF group were all less than that in the MEF group (P < 0.05). The complication rate was 35.5% in the HEF group, while 45.5% in the MEF group. There was no statistically significant difference between the two groups in ASAMI scores (P > 0.05). CONCLUSION: There is no statistically significant difference in finally clinical outcomes between hexapod external fixator and monolateral external fixator in the definitive treatment of high-energy tibial diaphyseal fractures. The hexapod external fixation treatment is a superior effective method, including advantages of stable fixation, less surgical duration, postoperatively satisfactory fracture reduction, and fewer complications.

Epidemiology of proximal and diaphyseal humeral fractures in children: an observational study from the Swedish Fracture Register.

BACKGROUND: Most fractures in children are fractures of the upper extremity. Proximal and diaphyseal humeral fractures account for a minority of these fractures. To our knowledge, few previous reports address these fractures. This study aimed to describe the epidemiology and current treatment of proximal and diaphyseal humeral fractures by using the Swedish Fracture Register (SFR). METHODS: In this nationwide observational study from the SFR we analysed data on patient characteristics, injury mechanism, fracture classification and treatment. We included patients aged < 16 years at time of injury with proximal or diaphyseal humeral fracture registered in 2015-2019. RESULTS: 1996 (1696 proximal and 300 diaphyseal) fractures were registered. Proximal fractures were more frequent in girls whereas diaphyseal fractures were more frequent in boys. The median age at fracture was 10 years in both fracture types but patient's age was more widespread in diaphyseal fracture (IQR 5-13 compared to IQR 7-12 in proximal). In both sexes, the most registered injury mechanism was fall. Horse-riding was a common mechanism of injury in girls, whereas ice-skating and skiing were common mechanisms in boys. Most proximal fractures were metaphyseal fractures. Most diaphyseal fractures were simple transverse or oblique/spiral fractures. The majority of fractures were treated non-surgically (92% of proximal and 80% of diaphyseal fractures). The treatment method was not associated with the patient's sex. Surgery was more often performed in adolescents. The most common surgical methods were K-wire and cerclage fixation in proximal fracture and intramedullary nailing in diaphyseal fracture. CONCLUSION: Following falls, we found sex-specific sport activities to cause most proximal and diaphyseal paediatric fractures. Further studies on prophylactic efforts in these activities are needed to investigate whether these fractures are preventable. The majority of the fractures were treated non-surgically, although surgical treatment increased with increasing age in both sexes. TRIAL REGISTRATION: Not applicable. The present study is a register-based cohort study. No health care intervention had been undertaken.

Radiographic Determination of the Distal Ulnar Diaphyseal Angle.

PURPOSE: Characterizing the distal ulnar diaphyseal angle (DUDA) may be important for anatomic recreation of the distal ulna during ulnar shortening osteotomy procedures using conventional straight plates. This study characterized the DUDA and determined side-to-side, age, and sex effects on DUDA magnitudes and locations. METHODS: Retrospective analyses of bilateral wrist radiographs were performed on 60 patients. The DUDA was defined as the angle of intersection between a line passing through the center of the distal ulnar metadiaphyseal region, in line with the landmarked long axis of the ulna, on a lateral radiograph. This inflection point was measured from the most distal aspect of the ulnar head and recorded as the DUDA tip-to-apex distance (TAD). Rater reliability was determined using the intraclass correlation coefficient. RESULTS: We found DUDAs in 94% of radiographs. The mean DUDA angle was 5.6° ± 2.6° and the mean TAD was 45.3 ± 9.5 mm. The Pearson correlation coefficients for side-to-side comparisons were 0.47 for the DUDA angle and 0.69 for the TAD. For male and female patients, the mean DUDAs were 5.4° ± 2.3° and 5.9° ± 2.9°, respectively, and the mean TADs were 47.8 ± 9.7 mm and 41.7 ± 7.9 mm, respectively. The DUDA angle and TAD had negligible associations with age (r = -0.15 and -0.08, respectively). At 0.74 (95% CI, 0.58-0.85), interrater reliability was good. At 0.93 (95% CI, 0.88-0.96), intrarater reliability was excellent. CONCLUSIONS: We demonstrated DUDAs, representing valgus deviations from the center axis and anteroposterior views of the ulna. Contralateral lateral wrist radiographs are moderate to strongly reliable in determining a DUDA. Rater reliability was good to excellent. CLINICAL RELEVANCE: Re-creation of the DUDA may benefit procedures such as ulnar shortening osteotomy, fractures, or malunion by contributing to knowledge of distal radioulnar joint biomechanics.

Femur morphology in healthy infants and young children.

The objective of this study was to characterize femur morphology in healthy infants and young children. Anterior-posterior (AP) radiographs of the femur from children age 0-3 years with no history of bone disease were obtained from two children's hospitals and one medical examiner's office. Femur morphological measures (bone length, minimum diaphysis diameter, growth plate width, and femur radius of curvature) and sectional structural measures were determined. Measures were described and compared based on subject age and mass. Relationships between measures and age and mass were evaluated. The 169 AP femur radiographs were obtained from 99 children (59.6% males, median age = 12.0 months, IQR = 0-27.5 months, median body weight = 10.0 kg, IQR = 4.4-15.6 kg). Femur length (rs  = 0.97, p < 0.001; rs  = 0.89, p < 0.001), trochanter width (rs  = 0.86, p < 0.001; rs  = 0.85, p < 0.001), minimum diaphysis diameter (rs  = 0.91, p < 0.001; rs  = 0.87, p < 0.001), and growth plate width (rs  = 0.91, p < 0.001; rs  = 0.84, p < 0.001) increased with age and weight, respectively. Cross-sectional area (rs  = 0.87; rs  = 0.86; p < 0.01), polar moment of inertia (rs  = 0.91; rs  = 0.87; p < 0.001), moment of inertia (rs  = 0.91; rs  = 0.87; p < 0.001), polar modulus (rs  = 0.91; rs  = 0.87; p < 0.001) and medullary canal diameter (rs  = 0.83, p < 0.001; rs  = 0.73, p < 0.001) at the minimum diaphysis also increased with age and weight, respectively. Changes during rapid bone growth are important to understanding fracture risk in infants and young children as they transition to independent walking. Femur length, trochanter width, minimum diaphysis diameter and growth plate width increased with age and weight. Structural properties associated with fracture resistance also increased with age and weight.

Closed reduction and locked intramedullary nailing of diaphyseal long bone fractures without intra-operative imaging and fracture table.

PURPOSE: Early closed reduction and locked intramedullary (IM) nailing has become the standard treatment for diaphyseal long bone fractures in high income countries. The low and middle income countries (LMICs) are still lagging behind in transiting from open surgical reduction and non-operative modalities to closed reduction due to lack of requisite equipment. However, some surgeons in LMICs are beginning to achieve closed reduction even without the equipment. METHODS: A prospective descriptive study was done on a total of 251 fresh diaphyseal fractures of the humerus, femur and tibia fixed with a locked nail over a 5½-year period. The fractures were grouped into those that had open reduction, closed reduction or reduction with a finger. RESULTS: Closed reduction was done for 135 (53.8%) fractures belonging to 123 patients. The mean and range of the patients' ages were 41.33 and 13-81 years, respectively. Males constituted 69.9% and mostly (48%) sustained fractures in motorcycle accident. There was a significant negative association between closed reduction and fracture-to-surgery interval (p < 0.001). Closed reduction also had positive associations with: (i) humerus and tibia fractures (p < 0.001), (ii) middle, distal and segmental fractures (p = 0.025), (iii) retrograde approach to femur fracture nailing (p < 0.001), and (iv) wedge or multifragmentary type femur fractures (p = 0.005). CONCLUSION: With constant practice, it is possible to achieve closed reduction of many fresh diaphyseal long bone fractures in spite of the limitations imposed on surgeons in LMICs by poor health systems and grossly inadequate fracture care facilities.

Focal Dome Osteotomy for the Treatment of Diaphyseal Malunion of the Lower Extremity.

The treatment of malunion of the lower extremity diaphysis is challenging. Diaphyseal osteotomies require extra care to promote bone healing. This may be enhanced through osteotomies, which do not produce bone gaps and allow for compression. The focal dome osteotomy allows for rotation around an axis to correct angular deformity. The production of a successful arcuate or focal dome osteotomy requires a suitable soft tissue host. The deformity analysis is not complex but essential to assess the feasibility of correction and is required for perfect execution of the osteotomy. This tutorial explains the technique for focal dome osteotomy to correct angular deformities of the lower extremities, specifically in the diaphysis. Surgical correction for malunion, infected malunion, and infected mal-nonunion case examples are discussed. With meticulous planning and surgical technique, the focal dome osteotomy is a viable option for correcting diaphyseal malunions with compression techniques that allow a stable construct for early weight-bearing.

Morphological divergence in the curvature of human femoral diaphyses: Tracing the central mass distributions of cross-sections.

The diaphysis of the human femoral bone has a physiological anterior curvature; additionally, there is a curvature to the medial side or lateral side. In addition to compression stress from gravity during standing, walking, and running, these bones are continuously exposed to complex stresses from the traction forces of the various strong muscles attached to them. The femoral diaphysis is subjected to these mechanical stresses, and the direction and size of its curvature are defined according to Wolff's law and the mechanostat theory of Frost. The purpose of this study was to quantitatively evaluate the curvature of the femoral diaphysis in Japanese skeletons by determining the curve connecting the central mass distributions (CMD) of cross-sectional images. A total of 90 right femora (46 males and 44 females) were randomly selected from modern Japanese skeletal specimens. Full-length images of these bones were acquired using a clinical computed tomography scanner. The range between the lower end of the lesser trochanter and the adductor tubercle of each femur was divided at regular intervals to obtain ten planes, and nine levels were analyzed. The CMD curve was determined by connecting the CMDs of each of the nine cross-sections. First, the CMD of a cross-section in each of the nine slices was calculated, and the nine trajectories were superimposed from above. Then, by converting the shape of the entire CMD curve to superimpose the coordinates of the endpoint on the starting point, a closed arc representing the curvature of the femur was determined. For both males and females, the patterns varied from mostly medial to largely lateral curvature. The size of the curvature also varied for individuals. By analyzing only the coordinates of the vertex of the CMD curve of each femoral bone, the outlines of the diaphyseal curvatures could be recognized. The femora were thereby divided into two groups: medial bending and lateral bending. Considering males and females together, the number in the lateral-curvature group (n = 51) was larger than that in the medial-curvature group (n = 39). Moreover, the average age of the lateral-curvature group was significantly higher than that of the medial-curvature group (p < 0.05). In males, with an increase in the cortical bone proportion of the cross-sectional area, the anterior vertex of diaphyseal bending tended to be more prominent. This cortical proportion was significantly higher in the medial-curvature groups than in the lateral-curvature group (p < 0.01). The phenomena observed in this study may be related to pathophysiologies such as atypical fractures of the femur and osteoarthritis of the knee joints.

Cortical parameters predict bone strength at the tibial diaphysis, but are underestimated by HR-pQCT and µCT compared to histomorphometry.

Cortical bone and its microstructure are crucial for bone strength, especially at the long bone diaphysis. However, it is still not well-defined how imaging procedures can be used as predictive tools for mechanical bone properties. This study evaluated the capability of several high-resolution imaging techniques to capture cortical bone morphology and assessed the correlation with the bone's mechanical properties. The microstructural properties (cortical thickness [Ct.Th], porosity [Ct.Po], area [Ct.Ar]) of 11 female tibial diaphysis (40-90 years) were evaluated by dual-energy X-ray absorptiometry (DXA), high-resolution peripheral-quantitative-computed-tomography (HR-pQCT), micro-CT (µCT) and histomorphometry. Stiffness and maximal torque to failure were determined by mechanical testing. T-Scores determined by DXA ranged from 0.6 to -5.6 and a lower T-Score was associated with a decrease in Ct.Th (p ≤ 0.001) while the Ct.Po (p ≤ 0.007) increased, and this relationship was independent of the imaging method. With decreasing T-Score, histology showed an increase in Ct.Po from the endosteal to the periosteal side (p = 0.001) and an exponential increase in the ratio of osteons at rest to those after remodelling. However, compared to histomorphometry, HR-pQCT and µCT underestimated Ct.Po and Ct.Th. A lower T-Score was also associated with significantly reduced stiffness (p = 0.031) and maximal torque (p = 0.006). Improving the accuracy of Ct.Po and Ct.Th did not improve prediction of the mechanical properties, which was most closely related to geometry (Ct.Ar). The ex-vivo evaluation of mechanical properties correlated with all imaging modalities, with Ct.Th and Ct.Po highly correlated with the T-Score of the tibial diaphysis. Cortical microstructural changes were underestimated with the lower resolution of HR-pQCT and µCT compared to the histological 'gold standard'. The increased accuracy did not result in an improved prediction for local bone strength in this study, which however might be related to the limited number of specimens and thus needs to be evaluated in a larger collective.

Relationship between bone strength index of the hemiparetic tibial diaphysis and muscle strength in people with chronic stroke: influence of muscle contraction type and speed.

This study was conducted to examine the association between the tibial bone strength index and leg muscle strength of different contraction types and speeds among people with chronic stroke. We found that concentric muscle power at moderate speed was more associated with tibial bone strength index than other types. INTRODUCTION: To compare the influence of muscle strength of different contraction types and speeds on the bone strength index of tibial diaphysis in people with chronic stroke. METHODS: Eighty individuals with chronic stroke (age: 62.6 ± 8.0 years; men/women: 46/34; post-stroke duration: 9.0 ± 5.4 years) underwent scanning of the tibia at the 66% site on both sides using peripheral quantitative computed tomography. Each participant was also evaluated for isometric and dynamic (at 60°/s and 120°/s) strength of knee flexors/extensors and ankle dorsiflexors/plantarflexors using an isokinetic dynamometer. For a given contraction type and speed, the strength values of the four muscle groups were summed to yield a composite score. Multiple regression analysis was used to identify the association of the percent side-to-side difference (%SSD) in tibial polar-stress-strain index (p-SSI) with %SSD in muscle strength of different contraction types and speeds. RESULTS: The p-SSI and all muscle strength parameters on the paretic side had lower values than the non-paretic side (p ≤ 0.001). The %SSD in concentric muscle power at angular speed of 60°/s (R2 = 0.317, p = 0.006) and 120°/s (R2 = 0.298, p = 0.020) remained independently associated with that in p-SSI, after controlling for age, sex, body mass index, post-stroke duration, motor impairment, spasticity, and physical activity level. The effect of isometric strength and eccentric muscle power was not significant in multivariate analysis. CONCLUSIONS: Concentric muscle power was more predictive of %SSD in p-SSI at the tibial diaphysis than other contraction types and may be an important target for intervention to promote bone health in people with chronic stroke.

Mapping cortical bone stiffness and mineralization from endosteal to periosteal surfaces of bovine mid-diaphyseal femur.

INTRODUCTION: While bone literature abounds with correlations of mechanical stiffness to mineralization, such correlations are reported without relating the findings to specific intracortical locations. This study reports on mapping of stiffness and mineralization distributions in ring-shaped cortical bone samples sliced from mid-diaphyseal bovine femur. Stiffness and mineralization measurements were conducted at points across the intracortical thickness along radial lines emanating from the inner (endosteal) surface to the outer (periosteal) surface. Measurements were taken along approximately 4 mm distance of cortical bone thickness. MATERIALS AND METHODS: Three experimental techniques were employed: Vickers microhardness (HV), energy-dispersive X-ray (EDX) spectroscopy, and computed tomography (CT). Stiffness values were extracted from the Vickers microhardness tests. Elemental mineralization values (calcium %wt. and phosphorus %wt.) were determined from EDX data. All measurements were repeated on three different femur bones taken from different bovines (collected fresh from butcher). RESULTS: The study plots stiffness values and elemental mineralization (calcium %wt. and phosphorus %wt.) versus cortical thickness. Both stiffness and Ca %wt. and P %wt. are found to track and to linearly increase when plotted along the radial distance. The stiffness and mineralization trends collected from Vickers and EDX measurements were verified by employing the CT number (Hounsfield units, HU) via CT scans of the same bone samples. Data fitting via statistical methods revealed that all correlations were statistically significant. CONCLUSION: Starting from endosteal to periosteal surfaces of mid-diaphyseal bovine femur, it was found that stiffness, mineralization, and HU values all exhibit increasing and correlating trends.

Changes in the intra- and peri-cellular sclerostin distribution in lacuno-canalicular system induced by mechanical unloading.

INTRODUCTION: Mechanical stimuli regulate Sclerostin (Scl), a negative regulator of bone formation, expression in osteocytes. However, the detailed Scl distribution in osteocytes in response to mechanical unloading remains unclear. MATERIALS AND METHODS: Twelve-week-old male rats were used. The sciatic and femoral nerves on the right side were excised as mechanical unloading treatment. A sham operation was performed on the left side. One week after neurotrauma, the bone density of the femora was evaluated by peripheral quantitative computed tomography, and immunofluorescence was performed in coronal sections of the femoral diaphysis. The mean fluorescence intensity and fluorescent profile of Scl from the marrow to the periosteal side were analyzed to estimate the Scl expression and determine to which side (marrow or periosteal) the Scl prefers to distribute in response to mechanical unloading. The most sensitive region indicated by the immunofluorescence results was further investigated by transmission electron microscopy (TEM) with immunogold staining to show the Scl expression changes in different subcellular structures. RESULTS: In femur distal metaphysis, neurotrauma-induced mechanical unloading significantly decreased the bone density, made the distribution of Scl closer to the marrow on the anterior and medial side, and increased the Scl expression only on the lateral side. TEM findings showed that only the expression of Scl in canaliculi was increased by mechanical unloading. CONCLUSIONS: Our results showed that even short-term mechanical unloading is enough to decrease bone density, and mechanical unloading not only regulated the Scl expression but also changed the Scl distribution in both the osteocyte network and subcellular structures.

Differences in fetal fractional limb volume changes in normal and gestational diabetic pregnancies: an exploratory observational study.

OBJECTIVE: Fetal fractional limb volume has been proposed as a useful measure for quantifying fetal soft tissue development. The aim of this study was to investigate the growth of fractional arm volume (AVol) and fractional thigh volume (TVol) of fetuses with maternal gestational diabetes (GDM) compared with those of fetuses with normal glucose tolerance (NGT). We hypothesised fetal fractional limb volume would be larger in the GDM group than in the NGT group in late gestation. DESIGN: Exploratory observational study. SETTING: Saitama Municipal Hospital. SAMPLE: A total of 165 (125 NGT and 40 GDM) singleton Japanese pregnant women. METHODS: AVol and TVol were assessed between 20 and 37 weeks' gestation as cylindrical limb volumes based on 50% of the fetal humeral or femoral diaphysis length. Women were diagnosed as GDM based on the criteria of the Japan Society of Obstetrics and Gynecology. MAIN OUTCOME MEASURES: AVol and TVol were compared between women with NGT and those with GDM at each gestational age period (2-week intervals from 20 to 37 weeks' gestation). RESULTS: Overall, 287 ultrasound scans were performed (NGT group, 205 scans; GDM group, 82 scans). There was no significant difference of AVol between the groups before 32 weeks' gestation. AVol was significantly larger in the GDM group than in the NGT group after 32 weeks' gestation (P < 0.05). TVol was not statistically different between the groups across gestation. CONCLUSIONS: Detection of variations in fetal AVol may provide greater insight into understanding the origins of altered fetal body proportion in GDM. TWEETABLE ABSTRACT: AVol, but not TVol, is significantly larger in fetuses with GDM than in those with NGT after 32 weeks' gestation.

morphomap: An R package for long bone landmarking, cortical thickness, and cross-sectional geometry mapping.

OBJECTIVES: This study describes and demonstrates the functionalities and application of a new R package, morphomap, designed to extract shape information as semilandmarks in multiple sections, build cortical thickness maps, and calculate biomechanical parameters on long bones. METHODS: morphomap creates, from a single input (an oriented 3D mesh representing the long bone surface), multiple evenly spaced virtual sections. morphomap then directly and rapidly computes morphometric and biomechanical parameters on each of these sections. The R package comprises three modules: (a) to place semilandmarks on the inner and outer outlines of each section, (b) to extract cortical thicknesses for 2D and 3D morphometric mapping, and (c) to compute cross-sectional geometry. RESULTS: In this article, we apply morphomap to femora from Homo sapiens and Pan troglodytes to demonstrate its utility and show its typical outputs. morphomap greatly facilitates rapid analysis and functional interpretation of long bone form and should prove a valuable addition to the osteoarcheological analysis software toolkit. CONCLUSIONS: Long bone loading history is commonly retrodicted by calculating biomechanical parameters such as area moments of inertia, analyzing external shape and measuring cortical thickness. morphomap is a software written in the open source R environment, it integrates the main methodological approaches (geometric morphometrics, cortical morphometric maps, and cross-sectional geometry) used to parametrize long bones.

Identifying and Assessing Inter-Muscular Fat at the Distal Diaphyseal Femur Measured by Peripheral Quantitative Computed Tomography (pQCT).

INTRODUCTION: Inter-/intramuscular fat can be assessed with peripheral Quantitative Computed Tomography (pQCT) and is of interest as an indicator of "muscle quality." Typical pQCT scan sites (forearm, lower leg) have a low amount of inter-/intramuscular fat, however distal diaphyseal femur scan sites with conspicuous inter-/intramuscular fat have been identified as potentially more prudent scan sites, even in healthy adolescents. However, current state of the art analysis methods require labor-intensive manual segmentation of the scan. The purpose of the present study was to evaluate the reliability of a novel open source automated enclosing convex polygon approach (source code https://github.com/tjrantal/pQCT, commit cec9bce) to quantify inter-/intramuscular fat from femoral pQCT scans in healthy adults. METHODOLOGY: The distal diaphyseal femur (25% of tibial length from the knee joint towards the hip) of 27 adults aged 18-50 yr were scanned twice, 1 wk apart, using pQCT. Subcutaneous fat, muscle, inter-/intramuscular fat, and marrow areas, and corresponding densities were evaluated using a method we have reported previously, as well as the novel enclosing convex polygon method. RESULTS: The session-to-session reliability of the assessments was fair to excellent using the previously reported method as indicated by intraclass correlation coefficient (ICC2,1) ranging from 0.45 to 1.00, while the novel method produced excellent reliability (ICC2,1 0.78-1.00). CONCLUSION: Distal diaphyseal femur appears to be a potentially informative and prudent scan site for inter-/intramuscular fat evaluation with pQCT.