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Use of a medial bone plate for repair of radius and ulna fractures in dogs and cats: a report of 22 cases.

OBJECTIVE: This study evaluates the technique of medial bone plating in the repair of radius fractures in dogs and cats. STUDY DESIGN: A retrospective study was made of patients diagnosed with fractures of the radius that were stabilized by application of a bone plate to the medial side of the bone. ANIMAL POPULATION: Sixteen client-owned dogs and 4 client-owned cats. The animals' ages varied from 5 months to 8 years, and their weight varied from 1.3 to 49 kgs. METHODS: Animals were evaluated using radiography or client assessment, or both. RESULTS: Medical plate application was technically easier to do than cranial plate application, the technique avoided the extensor tendons, and permitted greater versatility in the selection of smaller plates for the fixation of distal radius fractures. All fractures repaired by this method healed with no postoperative complications. CONCLUSIONS: Medial plate application may be used for osteosynthesis of distal or middiaphyseal radius fractures. Further studies are needed to evaluate the use of this technique in morphologically complex fractures. In patients with fractures of the proximal radius, cranial plate application is considered more appropriate. CLINICAL RELEVANCE: Medial plating of radial fractures has significant advantages compared with conventional plate application; it provides the surgeon with an alternative method of fixation for selected radius fractures in dogs and cats.

Animals↗

PubMed2005

Growth patterns at distal radius and tibial shaft in pubertal girls: a 2-year longitudinal study.

UNLABELLED: Bone changes, in terms of both size and BMD, were assessed longitudinally in pubertal girls. Before puberty, BMD at the distal radius declined, whereas bone size increased, suggesting that normal growing girls experience a transient period of increased bone fragility. This could explain the elevated low-trauma forearm fracture rates reported in earlier studies. INTRODUCTION: Longitudinal data on bone growth during puberty are sparse. Such information is needed to understand the sequence of biological changes, the physical and mechanical consequences for the growing skeleton, and the implications for later life. MATERIALS AND METHODS: The geometric properties and volumetric BMD (vBMD) of the distal radius and tibial shaft were measured using pQCT in 258 pubertal girls followed over 2 years. A new hierarchical linear statistical modeling approach was used to determine true longitudinal trends. RESULTS: The growth rates of cross-sectional area (CSA) and BMC of the distal radius peaked at 16 and 9 months before menarche, respectively. This growth asynchrony between bone size and mass meant that total vBMD of the distal radius declined until 1 year before menarche. At the tibial shaft, total vBMD and cortical vBMD increased monotonically without any such transient reduction. Cortical thickness increased linearly, which was accounted for mainly by bone formation at the periosteal surface before menarche, but by both periosteal and endocortical apposition after menarche. During puberty, the ratio of cortical-to-total CSA of the tibial shaft increased and that of marrow-to-total CSA decreased. CONCLUSIONS: The temporal pattern of bone growth during puberty differs at the distal radius and tibial shaft. A transient decrease in vBMD, arising from asynchronous bone size and mass growth, occurs only at the radius. In the tibia, the mechanism of cortical thickening changes from periosteal apposition premenarche to both periosteal and endocortical apposition postmenarche.

Adolescent↗

PubMed2002

Radius bone strength in bending, compression, and falling and its correlation with clinical densitometry at multiple sites.

This study comprehensively analyzes the ability of site-specific and nonsite-specific clinical densitometric techniques for predicting mechanical strength of the distal radius in different loading configurations. DXA of the distal forearm, spine, femur, and total body and peripheral quantitative computed tomography (pQCT) measurements of the distal radius (4, 20, and 33%) were obtained in situ (with soft tissues) in 129 cadavers, aged 80.16 +/- 9.8 years. Spinal QCT and calcaneal quantitative ultrasound (QUS) were performed ex situ in degassed specimens. The left radius was tested in three-point bending and axial compression, and the right forearm was tested in a fall configuration, respectively. Correlation coefficients with radius DXA were r = 0.89, 0.84, and 0.70 for failure in three-point bending, axial compression, and the fall simulation, respectively. The correlation with pQCT (r = 0.75 for multiple regression models with the fall) was not significantly higher than for DXA. Nonsite-specific measurements and calcaneal QUS displayed significantly (p < 0.01) lower correlation coefficients, and QUS did only contribute to the prediction of axial failure stress but not of failure load. We conclude that a combination of pQCT parameters involves only marginal improvement in predicting mechanical strength of the distal radius, nonsite-specific measurements are less accurate for this purpose, and QUS adds only little independent information to site-specific bone mass. Therefore, the noninvasive diagnosis of loss of strength at the distal radius should rely on site-specific measurements with DXA or pQCT and may be the earliest chance to detect individuals at risk of osteoporotic fracture.

Absorptiometry, Photon↗

PubMed2005

External fixation and bone grafting for collapsed and comminuted distal radius fracture.

OBJECTIVE: To study the therapeutic effect of collapsed and comminuted distal radius fracture. METHODS: Twenty-six patients with collapsed and comminuted distal radius fracture were hospitalized from July 1998 to June 2003. All fractures were treated by the methods of open reduction, sustained bone grafting and passing joint external fixator to restore the anatomic shape of distal radius. RESULTS: All 26 cases were followed up, and the results showed that the fractures have been united radiographically. The joint surfaces were intact and there was no length discrepancy occurred in patient's radius. The average volar tilt was 6 to 15 degrees and the average ulnar tilt was 18 to 25 degrees. According to the Dieust criterion, 19 cases were rated as excellent and 7 as good. CONCLUSIONS: The method that applying passing joint external fixator and bone grafting for the treatment of collapsed and comminuted distal radius fracture could maintain the stability of fracture and restore the length of radius and the intact of joint surface.

Adult↗

PubMed1984

Does bone measurement on the radius indicate skeletal status? Concise communication.

Single-photon (I-125) absorptiometry was used to measure bone mineral content (BMC) of the distal third of the radius, and dual-photon absorptiometry (Gd-153) was used to measure total-body bone mineral (TBBM), as well as the BMC of major skeletal regions. Measurements were done in normal females, normal males, osteoporotic females, osteoporotic males, and renal patients. The BMC of the radius predicted TBBM well in normal subjects, but was less satisfactory in the patient groups. The spinal BMC was predicted with even lower accuracy from radius measurement. The error in predicting areal density (bone mass per unit projected skeletal area) of the lumbar and thoracic spine from the radius BMC divided by its width was smaller, but the regressions differed significantly among normals, osteoporotics, and renal patients. There was a preferential spinal osteopenia in the osteoporotic group and in about half of the renal patients. Bone measurements on the radius can indicate overall skeletal status in normal subjects and to a lesser degree in patients, but these radius measurements are inaccurate, even on the average, as an indicator of spinal state.

Adult↗

PubMed1995

Vulnerability of the posterior interosseous nerve during proximal radius exposures.

This study describes the anatomy of the posterior interosseous nerve and proposes how to protect it during the different approaches to the proximal radius. Based on the findings presented here, the choice of the approach and the pitfalls that might cause posterior interosseous nerve injury were defined. Three surgical approaches were used on 30 cadaveric upper limbs: modified Henry's anterior approach, Thompson's posterior approach, and a modified Gordon-Boyd's approach. Important anatomic structures were localized, marked, and shown on radiographs. Plates and screws were applied through the different approaches to determine the relationship of the hardware to the posterior interosseous nerve. Measurements were taken between the humeroradial joint, as a reference point, and different important anatomic structures. It was concluded that the anterior approach to the proximal radius is relatively safe and offers the possibility of proximal and distal extension. Caution should be taken while applying screws, however, to avoid posterior interosseous nerve injury. The radius is superficial posteriorly, and many surgeons favor Thompson's approach for exposure of the proximal radius; nonetheless, it carries the risk of posterior interosseous nerve injury with exposure of the most proximal portion of the radius. The modified Gordon-Boyd's approach offers the advantage of exposing both the radius and the ulna, but necessitates excessive muscle stripping.

Bone Plates↗

PubMed1994

[Complex distal radius fracture: value of spongiosa-plasty in combination with external fixator treatment].

22 Patients with complex fracture of the distal radius (Fernandez III/Frykman VII-VIII/AO 23.C) underwent treatment with external fixation and auxiliary autologous bone grafting in purpose to reconstruct and stabilize the radiocarpal articular surface, reset the radius length, obtain a quicker bone healing and avoid secondary radius shortening after removing of the external fixation. In spite of reassessment of radius length in 80% and reconstruction of the radiocarpal articular surface in 75%, late control showed the development of radiological signs of radiocarpal arthritis. 50% of the patients have a moderate loss of strength and motility in the wrist; this seems to be a good result for a very negative selection of complex fractures of distal radius. We recommend autologous bone grafting in treatment of complex fractures of the distal radius with external fixation.

Adult↗

PubMed2001

Sizing the radius of the pore formed in erythrocytes and lipid vesicles by the toxin sticholysin I from the sea anemone Stichodactyla helianthus.

The radius of the pore formed by sticholysin I and II (StI, StII) in erythrocytes and sticholysin I in lipid vesicles was investigated. The rate of colloid osmotic lysis of human erythrocytes, exposed to one of the toxins in the presence of sugars of different size, was measured. The relative permeability of each sugar was derived and the pore radius estimated with the Renkin equation. The radius was similar for sticholysin I and II and was independent of the reference sugar chosen and of the toxin concentration applied. It was also the same when erythrocytes were pretreated with different toxin doses in the presence of a polyethylene glycol (PEG) large enough to prevent lysis and thereafter transferred to solutions containing oligosaccharides of different size where they did lyse at different rates. The osmometric behavior of large unilamellar vesicles (LUV) was thereafter used to estimate the toxin lesion radius in a model system. LUV transferred to a hyperosmotic solution with a certain sugar immediately shrank and then re-swelled at a rate dependent on the bilayer permeability to water and sugar. When LUV were previously permeabilized with StI, only a fraction of them, namely those not carrying pores, continued to behave as osmometers. By increasing the size of the added sugar and approaching the pore radius, the fraction of osmometric LUV increased. Relative permeabilities were derived and used to estimate a channel radius around 1.2 nm, both for sugars and for PEGs. In conclusion the sticholysin pore has a constant size independent of toxin concentration and similar in natural and artificial membranes, suggesting it has a fixed predominant structure.

Animals↗

PubMed2004

Correction of permeability with pore radius of tight junctions in Caco-2 monolayers improves the prediction of the dose fraction of hydrophilic drugs absorbed by humans.

PURPOSE: To improve predictions of fraction dose absorbed (Fa) for hydrophilic drugs, a correction of paracellular permeability using the pore radius of tight junctions (TJs) in Caco-2 monolayers was performed. METHODS: The apparent permeability coefficient (P9app)) of drugs was measured using the Caco-2 assay and the parallel artificial membrane permeation assay (PAMPA), and values were corrected with the pore radius of TJs. RESULTS: An equation for calculating the pore radius of TJs from the P(app) of lucifer yellow was obtained. The optimal pore radius of TJs in Caco-2 monolayers for predicting human Fa was calculated to be 7 A. The correlation between the actual and predicted Fa was improved by using the P(app) corrected with the pore radius of TJs. Permeability in the PAMPA, which was corrected using the pore radius and membrane potential, was well correlated with that in the Caco-2 assay. Most of the hydrophilic drugs tested in this study were absorbed mainly through the paracellular pathway. CONCLUSIONS: The results suggest the necessity of optimizing paracellular permeation for the prediction of Fa, and also the importance of the paracellular pathway to the absorption of hydrophilic drugs. This method might contribute to the setting of appropriate dosages and the development of hydrophilic drugs.

Absorption↗

PubMed2002

Central corneal thickness, radius of the corneal curvature and intraocular pressure in normal subjects using non-contact techniques: Reykjavik Eye Study.

PURPOSE: To establish a population profile of central corneal thickness (CCT), radius of the corneal curvature (CC) and intraocular pressure (IOP) and the relationships between them using non-contact techniques. METHODS: We used a population-based random sample of 415 male and 510 female Caucasians aged 50 years and older. CCT and the radius of CC were measured with Scheimpflug anterior segment photography. IOP was measured with air-puff tonometry. RESULTS: The mean IOP of right eyes was 15.1 mmHg (SD 3.3) among men and 15.8 mmHg among women (SD 3.1), which is a statistically significant difference. The mean radius of CC for male right eyes was 7.78 (SD 0.60) and for females 7.62 (SD 0.58) which is also statistically significant. Mean CCT for male right eyes was 0.528 mm (SD 0.041) and for females 0.526 mm (SD 0.037), which is not a significant difference. Linear regression analysis shows no relationship between the radius of CC and IOP or between age and radius of CC. Linear regression analysis of the relationship between CCT and IOP suggests higher IOP measurements with thicker corneas. There was no significant correlation between age and CCT. CONCLUSION: IOP was found to be independent of age and significantly higher in females than in males. Radius of CC was found to be age-independent and significantly steeper in females than in males. CCT appears to be independent of age and gender. Greater CCT is associated with higher mean IOP.

Age Factors↗

PubMed1999

The EyeSys videokeratoscopic assessment of apical radius and p-value in the normal human cornea.

The EyeSys videokeratoscope was used to assess the corneal topography in 98 subjects. Scatterplots of distance squared versus radius squared were plotted for the near horizontal and near vertical principal meridians of the two eyes. The regression lines allowed calculation of the surface apical radius and the p-value. The group average apical radius was 7.93 mm (horizontal) and 7.78 mm (vertical). The group average p-value was 0.76 (horizontal) and 0.82 (vertical). Both apical radius and p-value were similar when comparing the two eyes for both the horizontal and the vertical meridians. The two meridians in a single eye, however, had different values for both apical radius and p-value. Male apical radii were longer than those of females but the p-values were the same. There is no apparent association between age and either apical radius or p-value for the subjects used in this study. The asphericity of the cornea does not show any apparent association with corneal curvature in this group of subjects.

Adult↗

PubMed2006

Evaluation of surface tension and Tolman length as a function of droplet radius from experimental nucleation rate and supersaturation ratio: metal vapor homogeneous nucleation.

Zinc and silver vapor homogeneous nucleations are studied experimentally at the temperature from 600 to 725 and 870 K, respectively, in a laminar flow diffusion chamber with Ar as a carrier gas at atmospheric pressure. The size, shape, and concentration of aerosol particles outcoming the diffusion chamber are analyzed by a transmission electron microscope and an automatic diffusion battery. The wall deposit is studied by a scanning electron microscope (SEM). Using SEM data the nucleation rate for both Zn and Ag is estimated as 10(10) cm(-3) s(-1). The dependence of critical supersaturation on temperature for Zn and Ag measured in this paper as well as Li, Na, Cs, Ag, Mg, and Hg measured elsewhere is analyzed. To this aim the classical nucleation theory is extended by the dependence of surface tension on the nucleus radius. The preexponent in the formula for the vapor nucleation rate is derived using the formula for the work of formation of noncritical embryo [obtained by Nishioka and Kusaka [J. Chem. Phys. 96, 5370 (1992)] and later by Debenedetti and Reiss [J. Chem. Phys. 108, 5498 (1998)]] and Reiss replacement factor. Using this preexponent and the Gibbs formula for the work of formation of critical nucleus the dependence of surface tension on the radius R(S) of the surface of tension is evaluated from the nucleation data for above-mentioned metals. For the alkali metals and Ag the surface tension was determined to be a strong function of R(S). For the bivalent metals (Zn, Hg, and Mg) the surface tension was independent of radius in the experimental range. A new formula for the Tolman length delta as a function of surface tension and radius R(S) is derived by integration of Gibbs-Tolman-Koenig equation assuming that delta is a monotonic function of radius. The formula derived is more correct than the Tolman formula and convenient for the elaboration of experimental data. Using this formula the values of delta are determined as a function of R(S) from the experimental nucleation data. It is determined that all the metals considered are characterized by strong dependence of delta on radius; for the bivalent metals delta changes sign.

Journal Article↗

PubMed2001

Link between diurnal stem radius changes and tree water relations.

Internal water reserves are depleted and replenished daily, not only in succulent plants, but also in trees. The significance of these changes in tissue water storage for tree water relations was investigated by monitoring diurnal fluctuations in stem radius. In 6-year-old potted Norway spruce (Picea abies (L.) Karst.) trees, whole-tree transpiration rate (T), sap flow at the stem base and fluctuations in stem radius were measured at 10-min intervals over eight successive weeks. The dynamics of diurnal water storage in relation to the daily course of water movement was simulated and the contribution of stored water to T quantified. The finding that, in P. abies, the course of bark water content is linearly coupled to stem radius fluctuations provided the basis for linking stem radius changes to a functional flow and storage model for tree water relations. This model, which consists of physical functions only and is driven by a single input variable (T), accurately simulates the diurnal course of changes in stem radius and water storage of the tree crown and stem. It was concluded that fluctuations were mainly determined by the course of transpiration. The availability of soil water and the degree to which storage tissues were saturated were also factors affecting the diurnal course of stem radius changes. Internally stored water contributed to daily transpiration even in well-watered trees, indicating that stored water plays an important role not only during periods of drought, but whenever water transport occurs within the tree. Needle and bark water reserves were most heavily depleted during transpiration. Together they supplied approximately 10% of daily T on sunny days, and up to 65% on cloudy days. On a daily basis, the crown (mainly needles) contributed approximately eight times more water to T than the stem (mainly bark). The depletion of the two storage pools and the water movements observed in the trees always occurred in the same sequence. In the morning, T first caused a depletion of the water stored in the crown. It then caused depletion of bark storage tissues at ever increasing distances from the needles. Up to 75% of the transpired water could be withdrawn from storage tissues when the increase in T reached a maximum.

Circadian Rhythm↗

PubMed2002

Intrafocal pinning of distal radius fractures: a simplified approach.

Distal radius fractures are not often treated by plastic surgeons. At the authors' institution, plastic surgery manages half of all traumas below the elbow, including distal radius and forearm fractures. This opportunity gives the residents a unique perspective for comprehensive training in treating upper extremity injuries. Because a distal radius fracture is the most common fracture of the upper extremity, the authors describe the use of intrafocal pinning as a simple and effective approach in the treatment of extra-articular distal radius fractures (Colles' fractures). They conducted a prospective study of 18 patients with Colles' fractures treated sequentially at their institution from 1998 to 2001 using this technique. They measured ulnar variance and palmar tilt of the distal radius at the time of injury, after closed reduction, immediately postoperatively, and 11 weeks postoperatively. Acceptable distal radius reduction aims to achieve at least neutral ulnar variance and 0-deg palmar tilt. Compared with closed reduction, they achieved superior anatomic reduction with intrafocal pinning: ulnar variance, +2.6 mm vs. -1.4 mm; palmar tilt, -13.3 deg vs. +2.1 deg). These results were stable at the 11-week follow-up. Intrafocal pinning is a valuable tool in the management of Colles' fractures. It is simple to perform and to teach, and it produces results that are superior to closed reduction alone.

Adolescent↗

PubMed1995

Accuracy of videokeratography for instantaneous radius in keratoconus.

PURPOSE: Present videokeratographs provide corneal radius of curvature measurements in terms of axial (sagittal) radius and, for some instruments, instantaneous (tangential) radius. The EyeSys videokeratograph allows conversion from axial to instantaneous radius based on an algorithm, which assumes a basic corneal shape of elliptical form. METHOD: We tested the accuracy of the EyeSys instantaneous radius algorithm for 29 keratoconic corneas using the criterion that instantaneous radius of the cone apex could be determined accurately by aligning the cone apex with the optic axis of the videokeratoscope. RESULTS: There was a close relation between the instantaneous values obtained from the regular and apex alignments for the 17 eyes with cone apices below 55 D (95% limits of agreement -0.39 to 1.49 D), but not for the 12 eyes above 55 D (95% limits of agreement -4.87 to 6.61 D). The mean distance of the cone position from the center of the map was 1.16 mm for the instantaneous map and 1.59 mm for the axial map. CONCLUSION: Assuming the criterion for accuracy to be the corneal radii found when the videokeratograph was aligned with the cone apex, the instantaneous map for the EyeSys videokeratograph at regular alignment provided reasonably valid measurements for corneas up to 55 D, but large errors existed for some corneas of higher power.

Adolescent↗

PubMed2004

Geometric studies on variable radius spiral cone-beam scanning.

The goal is to perform geometric studies on cone-beam CT scanning along a three-dimensional (3D) spiral of variable radius. First, the background for variable radius spiral cone-beam scanning is given in the context of electron-beam CT/micro-CT. Then, necessary and sufficient conditions are proved for existence and uniqueness of PI lines inside the variable radius 3D spiral. These results are necessary steps toward exact cone-beam reconstruction from a 3D spiral scan of variable radius, adapting Katsevich's formula for the standard helical cone-beam scanning. It is shown in the paper that when the longitudinally projected planar spiral is not always convex toward the origin, the PI line may not be unique in the envelope defined by the tangents of the spiral. This situation can be avoided by using planar spirals whose curvatures are always positive. Using such a spiral, a longitudinally homogeneous region inside the corresponding 3D spiral is constructed in which any point is passed by one and only one PI line, provided the angle omega between planar spiral's tangent and radius is bounded by [omega - 90 degrees] < or = < epsilon for some positive epsilon < or = 32.48 degrees. If the radius varies monotonically, this region is larger and one may allow epsilon < or = 51.85 degrees. Examples for 3D spirals based on logarithmic and Archimedean spirals are given. The corresponding generalized Tam-Danielsson detection windows are also formulated.

Biophysical Phenomena↗

PubMed1998

The association between rates of wear in retrieved acetabular components and the radius of the femoral head.

Current evidence suggests that loosening of the acetabular socket is related to the volume of ultra-high molecular weight polyethylene wear debris generated at the articulating surfaces, through a process of bone resorption. Therefore it is important that the rate of volumetric wear is minimized in an attempt to extend the useful life of the procedure. Laboratory evidence indicates that a reduction in sliding distance would be beneficial in achieving this target and may be attained by a reduction in femoral head radius. To investigate the relationship between femoral head size and the rates of both volumetric wear and penetration, 200 acetabular components were retrieved at the time of revision surgery. The joints had femoral heads ranging in size from 11.1 to 19.8 mm radius. For those sockets that were loose at revision surgery, a significant correlation was observed, between the rate of volumetric wear and the radius of the femoral head. For this cohort an increase in radius of 1 mm resulted in an increased rate of volumetric wear of 5.1 (SE 1.4) mm3/yr. However, the explained variance in the regression was low and exemplifies the multifactorial nature of the wear process. In particular, it is anticipated that the activity of the patient will have a significant effect on the rate at which the debris is produced. No significant correlation was observed between the rate of linear wear and femoral head radius. These results would indicate a benefit in using head sizes of a smaller radius, which generate debris at a reduced rate, and therefore require more time to accumulate large volumes of wear products.

Aged↗

PubMed1981

The radius of gyration of L-arabinose-binding protein decreases upon binding of ligand.

The technique of small angle x-ray scattering has been employed to study the effect of sugars on the radius of gyration of the L-arabinose-binding protein, a component of the high affinity L-arabinose transport system in Escherichia coli. We find that the binding of L-arabinose to the "sugar-free" protein in solution causes a 0.94 +/- 0.33 A decrease in the radius of gyration while D-glucose, a nonbinder, produces no such effect. The radius of gyration calculated from the complete atomic co-ordinates of the crystal structure of L-arabinose-binding protein (solved with bound L-arabinose) corresponds to the experimentally determined value for the radius of gyration in the presence of L-arabinose. This reduction in radius of gyration can be best accounted for in terms of a substrate-induced cleft closure in which one lobe rotates relative to the other lobe. A compute modeling study indicates that a rotation of 18 degrees about a hinge deep in the base of the sugar-binding cleft between the two domains would produce the observed decrease in the radius of gyration. The findings (Newcomer, M. E., Gilliland, G. L., and Quiocho, F. A. (1981) J. Biol. Chem. 256, 13213-13222) that the L-arabinose molecule embedded in the cleft between two domains is completely inaccessible to the solvent is consistent with a closing of the cleft between the two lobes.

Arabinose↗