Area Of Mid-shaft Research Articles

The issues and complexities of establishing methodologies to differentiate between vertical and horizontal impact mechanisms in the analysis of skeletal trauma: An introductory femoral test

Understanding skeletal trauma characteristics is fundamental for the examination and interpretation of blunt force trauma (BFT). BFT is the most complex type of trauma to interpret based on the analysis of skeletal fractures alone, with comminuted fractures presenting additional complications to assess and interpret. Considerable variation exists within each type of BFT injury dependent on direction, magnitude of force, plus a myriad of biological/environmental factors. Given the complex processes governing the nature of BFT skeletal injuries determining whether differences between impact mechanisms and skeletal trauma can be quantified requires investigation. Aim: this study aims to determine the feasibility of quantifying outcomes between two separate loading conditions by using a formula created from transformed variables recorded from specific trauma cases involving BFT to the femur. Methodology: Displacement, comminution, and femoral midshaft area data were recorded from full body postmortem computed tomography scans of 103 individuals (males, mean age 42.5, and females, mean age 48.9) where cause of death was the result of rapid horizontal deceleration impact events (pedestrian motor vehicular accidents, n = 59) and vertical (>3-metre falls, n = 44). These measurements were standardised and transformed into a continuous variable. Independent t-tests, binary logistic regression and K Nearest- Neighbours (KNN) were used to analyse the data. Results: The standardised values showed mean group differences between falls (9.62) and pedestrian motor vehicular impacts (pedestrian MVAs) (9.53), however, these results were not statistically significant. The results indicate that similarities in variance between types of trauma outcomes and impact mechanisms demonstrate low equivalency (samples have limited differences), and the overall limitations in relying on using single elements to explain complex skeletal trauma outcomes.

“Wrap Around” Pedicled Muscle Flaps for the Treatment of Recurrent Forearm Synostosis

Three proximal and 2 mid shaft recurrent radioulnar synostoses were managed with a "wrap around" vascularized muscle interposition after excision of the heterotopic bone. A proximally pedicled brachioradialis flap was used for the proximal forearm and elbow synostoses, and the flexor carpi ulnaris muscle was used for the midshaft area. Anatomy of the flaps and the technical details of each procedure are thoroughly described. After a mean follow-up period of 8 years (range 3-14 years), there were no recurrences. The functional outcome regarding forearm rotation, elbow motion, and working capacity was highly satisfactory in all 5 patients.

Evidence for an extensive collagen type III proximal domain in the rat femur: II. Expansion with exercise

Exercise in youth may affect bone “quality” as well as quantity. Using the rat model, 1.5-month-old females were divided into four weight-matched groups, exercised short-term (6 weeks, E s, n = 20) and long-term (14 weeks, E L, n = 10) by access to monitored running wheels, and corresponding “sedentary” controls (S S short-term, n = 20; S L long-term, n = 10). Femora were either plastic-embedded or fresh-frozen. Transverse histological slices, 100 μm thick, were cut midshaft, while similar cryosections, 8 μm thick, were prepared from the same site and also coronal to the femoral neck region. An image analyser measured femoral neck and midshaft microarchitecture, while immunostaining localized collagen type III-rich fibres (CIII, an index of Sharpey fibre insertions) and osteopontin-rich osteons (OPN, an index of remodelling). Exercise increased cortical bone (proximal width +18%, midshaft area +7%). It also raised cancellous bone volume (+25%) by trabecular thickening (+30%) with more intraosseous vascularity and new trabecular interconnections (node-terminus ratio, +57%; trabecular pattern factor, −147%; marrow star volume. −48%). In the cortex a prominent discrete subperiosteal domain became wider (+50% midshaft) with exercise and contained more numerous (+15%) CIII-stained fibres. In contrast the encircled inner bone developed more numerous (+14%) OPN-rich osteons. It is concluded that short-term voluntary exercise augments both cortical and cancellous microarchitecture. It also alters protein composition, such that expanding arrays of Sharpey’s fibres within a circumferential proximal domain (Part I) interconnect more powerfully with the musculature and interface more robustly with the core bone that in response becomes more vascular and biodynamic, providing further insight into how muscle mass may be skeletally translated.

Pediatric forearm fractures: Indications, technique, and limits of conservative management

Although several minimal invasive techniques for the operative management of pediatric forearm fractures have been developed recently, conservative treatment still remains the option with the lowest risk for small patients. We present the results of our clinical and radiological follow-up after an average of 52.4 months (4-112) in 102 pediatric patients. All fractures were treated conservatively. There were 68 fractures (66.7 %) of the distal third of the forearm, 30 fractures (29.4 %) of the midshaft area, and four fractures (3.9 %) in the proximal third of the shaft. Greenstick fractures were seen in 58 cases (56.8 %), complete fractures with displacement of both corticalices in 26 patients (25.5 %), and folding fractures in 18 cases (17.7 %). With the exception of one fracture with the necessity of remanipulation after redisplacement in the cast, all fractures healed uneventfully without any further intervention. Functional results were excellent with a free range of motion of the wrist and elbow and without any signs of muscular atrophy in 96 children (94.1 %) at the time of follow-up. Six patients, however, showed a significant loss of forearm rotation of an average of 25 degrees (15 degrees -50 degrees ). In four of these six patients, the fracture had been situated in the proximal and midshaft area. Thus, two out of four fractures of the proximal forearm (50.0 %) showed a poor functional outcome. On the basis of our data we recommend conservative management for (closed) pediatric fractures of the distal and midshaft area. Operative treatment is indicated in forearm fractures close to the elbow.

Pediatric forearm fractures: indications, technique, and limits of conservative management

Although several "minimal invasive" techniques for the operative management of pediatric forearm fractures have been developed recently, conservative treatment still remains the option with the lowest risk for small patients. We present the results of our clinical and radiological follow-up after an average of 52.4 months (4-112) in 102 pediatric patients. All fractures were treated conservatively. There were 68 fractures (66.7 %) of the distal third of the forearm, 30 fractures (29.4 %) of the midshaft area, and four fractures (3.9 %) in the proximal third of the shaft. Greenstick fractures were seen in 58 cases (56.8 %), complete fractures with displacement of both corticalices in 26 patients (25.5 %), and folding fractures in 18 cases (17.7 %). With the exception of one fracture with the necessity of remanipulation after redisplacement in the cast, all fractures healed uneventfully without any further intervention. Functional results were excellent with a free range of motion of the wrist and elbow and without any signs of muscular atrophy in 96 children (94.1 %) at the time of follow-up. Six patients, however, showed a significant loss of forearm rotation of an average of 25 degrees (15 degrees -50 degrees ). In four of these six patients, the fracture had been situated in the proximal and midshaft area. Thus, two out of four fractures of the proximal forearm (50.0 %) showed a poor functional outcome. On the basis of our data we recommend conservative management for (closed) pediatric fractures of the distal and midshaft area. Operative treatment is indicated in forearm fractures close to the elbow.

The effect of local controlled release of sodium fluoride on the stimulation of bone growth.

This study was performed to test the feasibility of using a biodegradable delivery system for the local controlled release of sodium fluoride as a mechanism for the stimulation of local bone growth. Sodium fluoride grains were mixed with poly-DL-lactic acid (PLA), and the mixture was then dissolved in acetone. After driving off the solvent, sheets of this material were rolled into rods 3.2 mm in diameter and 28.6 mm long. These were inserted into the intramedullary canals of the right femora of adult New Zealand White rabbits. A sham implant, made the same way but containing no fluoride, was inserted into the contralateral left leg. The effects of three different concentrations of sodium fluoride, 0.125 g NaF/g PLA, 0.250 g NaF/g PLA, and 0.500 g NaF/g PLA, were determined after a 4-week implantation period. In a second set of experiments, the concentration was fixed at 0.500 g NaF/g PLA with implantation durations of 4, 8, and 16 weeks. Expressed in terms of property ratios (experimental/control), bending strengths of the femora were significantly raised in most groups with the notable exception of Group 3 (0.500 g NaF/g PLA, 4 weeks). Cross-sectional area ratios in the distal femora were increased in all groups compared to right/left values for a normal unoperated group (p less than 0.05), with the highest ratio being 1.50 (SD = 0.44) for Group 4 (0.500 g NaF/g PLA, 8 weeks). Only Group 4 animals showed significant (p less than 0.05) increases in midshaft area ratio and none had responses proximally. Growth rates, measured by sequential fluorochrome labeling of bone followed the area ratio data and were only significant for the distal femora.

A New Femoral Component Design Based on the Trabecular Systems of the Proximal Femur

This investigation presents a new design of the femoral component used in total hip arthroplasty. The design utilizes a tensile component which screws into the femoral stem from the lateral side of the femur. The potential advantages of utilizing such a component are 1) PMMA cement may be not needed to hold the implant in place, 2) better stress distribution in the region of the greater trochanter is achieved, 3) reduced stress levels in the implant, and 4) the femoral stem may be shortened to reduce the amount of reaming required. Two dimensional, plane stress finite element models of the proximal end of a normal femur, a femur with the new implant design, and a femur with a control Charnley-Cobra femoral component were developed. Loads simulating a one-legged stance were applied on the models. The normal and shear stresses, the octehedral shearing stress and the directions of principal stress were calculated for comparison with the normal femur. There was distinct improvement in bone stress distribution for the femur with the experimental implant as compared to the femur with the control prosthesis. The stress concentration normally observed in the mid-shaft area of the Charnley femoral stem was also not seen in the new design.

Femoral mechanics in the lesser bushbaby (Galago senegalensis): structural adaptations to leaping in primates.

One method used to examine the relationship between behavioral strategies and anatomical adaptation is to study the results of mechanical stress associated with a given behavior and compare this with skeletal adaptations to other behaviors. This comparative approach is appropriate for highlighting combinations of features that are specializations to specific types of behavior. The purpose of this paper is to compare femoral mechanics in Galago senegalensis with previously collected data for macaques and humans as a basis for discussing structural adaptations in the primate hindlimb to leaping. The stiffness and load carrying capabilities of the femoral diaphyses of 27 G. senegalensis were analyzed using the SCADS computer program. The data suggest that the galago femur is well adapted to sustain large sagittal plane compressive loads rather than large bending loads. The straightness of the femoral shaft and large midshaft area moments of inertia prevent buckling from these large compressive loads. Calculations indicate that the ratio of critical buckling load to body weight in galago is 31 times that in macaques and 55 times that in humans. The femur of this saltatory primate is morphologically adapted to resist buckling when subjected to large compressive loads, while those of macaques and humans are better adapted to resist bending moments caused by ground reaction forces acting on the extended limb. The differences between galago on the one hand and macaques and humans on the other suggest that relatively smaller moments about the hip and relatively larger moments about the knee accompany more quadrupedal and bipedal walking, while habitual leaping is associated with relatively larger moments about the hip. These data reinforce the apparent similarity of the mechanical effects of quadrupedal and bipedal locomotion on the femur and dissimilarity with femoral mechanics in habitually saltatory primates.

In utero allogeneic bone transplantation in primates: roentgenographic and histological observations.

Intrauterine allogeneic bone transplantation was performed on 25 monkey fetuses at 120 to 135 days of gestation. Two surgical techniques for orthotopic transplantation of the humeral midshaft were utilized: (1) A segment (5 to 7 mm) of fetal humerus was transplanted from fetus (donor) to fetus (recipient). An intramedullary pin (Kirschner orthopedic wire) was used for fixation of the severed humerus. (2) Without severing the humerus, a midshaft area (5 to 7 mm X 5 to 6 mm) was surgically ablated. A bone paste composed of crushed bone particles mixed with an agar-enriched culture medium was sculpted to fill this lesion. We used fresh frozen or fresh allograft tissue with equal success. Postsurgical observations included serial roentgenographic and histological evaluation of humeral osteogenesis, as well as postnatal assessment of limb use. The contralateral arm served as a control. Our findings indicate that the immune surveillance system of fetal monkeys may be tolerant of these bone allografts; alternatively, healing by substitution may also occur. The roentgenographic and histological results demonstrate that both of the transplantation procedures used here achieved restoration of the long bone. The use of bone paste allowed us to sculpt the allograft to the desired conformation. These results from laboratory primate models encourage continued investigation of fetal allogeneic bone transplantation, because of its ultimate potential for intrauterine repair of skeletal anomalies in man.

Confirmation of the sex difference in continuing subperiosteal apposition.

AbstractA major sex difference in the rate of continuing bone expansion was confirmed for 5660 adult subjects of European ancestry. The five‐decade gain in metacarpal midshaft area amounted to 8.4% in 3455 females and 2.8% in 2205 males. There was no systematic age effect on the length of the second metacarpal. Accordingly, both bone expansion and the marked sex difference in its magnitude may be attributed to sex‐specific aspects of ageing much like the sex difference in endosteal surface loss.