bluuebunny/crossref_metadata_2025_split huggingface dataset:
Correlations of radiographic analysis of healing fractures with strength: A statistical analysis of experimental osteotomies
Authors: Panjabi Manohar M. , Walter Stephen D. , Karuda Mark , White Augustus A. , Lawson Jack P. 
Published: February 2005

AbstractThe assessment of fracture healing strength using routine roentgenograms is difficult and controversial. There are few experimental data that correlate radiographic appearance with the actual quantitative strength of healing fractures. However, this method is widely used in clinical practice. A study is presented in which transversely osteotomized rabbit tibiae were allowed to heal for 3 to 8 weeks. A pair of orthogonal roentgenograms was taken of each bone and the bones were tested for strength in a dynamic torsion testing machine. Statistical analyses were done to study the correlations between the roentgenographic and strength parameters. Cortical continuity was found to be the best single predictor of strength of a healing fracture (correlation coefficient r = 0.80). The least important predictor was the callus area (r = 0.17). Fracture displacement, callus thickness, and callus diameter had negative correlations. From these experimental findings in an animal model, we conclude that even under laboratory conditions the information gained from plain radiographs is not sufficient to accurately predict the strength of a healing fracture.
Ultrastructural aspects of nerves, bones, and vessels in hereditary sensory neuropathy
Authors: Teot L. , Arnal F. , Humeau C. , Pous J. G. , Dimeglio A. 
Published: February 2005

AbstractThis study concerns two children, from the same otherwise normal family, presenting progressive spontaneous amputations of the limbs, suggesting peripheral hereditary sensory neuropathy. Samples from the distal nerves and vessels and the distal tibial epiphyses were examined ultrastructurally. The nerves showed signs of degeneration, and a typical bone necrosis, without osteoclasts, was observed in the 2 cm margin of the samples. Simultaneous modifications of the vessels suggest a neurally initiated vascular reflex resulting in bone destruction. Theories that might explain the observations are discussed.
Effects of prosthetic acetabular replacement on strains in the pelvis
Authors: Lionberger D. , Walker P. S. , Granholm J. 
Published: February 2005

AbstractThe effects of cemented acetabular components on the strains in the pelvis were determined experimentally. Four components were tested: A plain metal hemisphere: a metal hemisphere with a triflange; a hemisphere with an iliac peg; and a hemisphere with a complete flange and a peg. Loading was carried out in neutral, flexion, and extension directions. The subchondral one was only slightly reamed, and extension directions. The subchondral bone was only slightly reamed, and components were cemented and tested successively. For the intact hip joint, the strains on the superior acetabular rim were much lower than those on the posterior rim. After placement of the components, the tensile strains on the rim decreased by 22–54% while the compressive strains increased by 0–25%. The bone on the medial inferior surface was subjected ot 65% less tensile strain and 48% more compressive strain in neutral and extension loading. There were no great differences between the four styles of acetabular component.
Evaluation of tibiofibular motion under load conditions by computed tomography
Authors: Jend H.‐H. , Ney R. , Heller M. 
Published: February 2005

AbstractEvaluation of tibiofibular motion in vivo has been possible only by invasive methods. A new nonivasive method has been developed that uses computed tomography (CT). A special device was constructed for use on the CT table to study fibular motion with load placed across the ankle. From dorsal to plantar flexion the fibula moved 1.1 ± 0.4 mm medially with an accompanying nonsignificant ventral shift and medial rotation. Application of load across the ankle did not significantly alter these findings. In a subgroup of predominantly females, plantar flexion of the ankle provoked a dorsal fibular motion of 0.7 ± 0.8 mm. In this subgroup application of load across the ankle reduced the medial and dorsal motion during the accompanying plantar flexion. The mechanism of these different movements can be deduced from the morphology of the ankle joint and its ligamentous and muscular guidance mechanism. The variable axis of joint movement and the insertion of the lateral ligament forced the fibula anterior in plantar flexion. When external talar rotation is present, the normal fibular motion is prevented unless load is applied across the ankle. The new investigative procedure permits study of the sequelae of traumatic and iatrogenic injuries to the fibula.
Effect of EHDP on fracture healing in dogs
Authors: Lenehan Timothy M. , Balligand Marc , Nunamaker David M. , Wood Frederick E. 
Published: February 2005

AbstractEthane‐1‐hydroxy‐1, 1‐diphosphonate (EHDP) was administered subcutaneously to mature beagle dogs at dose levels of 0.1, 0.5, and 5.0 mg/kg/day for a 20 week period to determine the drug's effects healing. Uniform, transverse fractures of the midshaft radius were created in one limb and treated by external splintage. Drug‐induced effects on fracture healing were monitored radiographically, histologically, and histomorphometrically; mechanical properties of the healing bones were determined in 4‐point bending tests. At a dose of 0.1 mg/kg/day, ultimate load at failure and flexural rigidity of the fractured limbs equated or exceeded that of saline control animals, and radiographic healing was normal. At a dose of 0.5 mg/kg/day ultimate load at failure and flexural rigidity of the fractured limbs proved inferior to saline control values, and radiographic healing appeared delayed. At a dosage of 5.0 mg/kg/day, there was obvious radiographic nonunion, and the callus of fractured radii had little inherent flexural rigidity or strength. Histomorphometrically, no differences were noted between control animals and the 0.1 or 0.5 mg/kg/day group; however, mineralization activity activity appeared totally disrupted at the higher dosage level (5.0 mg/kg/day). In the 5.0 mg/kg/day group, EHDP‐induced effects proved reversible with mineralization evident as early as 3 weeks following drug withdrawal. In mature beagle dogs EHDP proved to have dose‐dependent and reversible inhibitory effects on secondary fracture healing.
Ultrastructure of electrically induced osteogenesis in the rabbit medullary canal
Authors: Brighton Carl T. , Hunt Robert M. 
Published: February 2005

AbstractThe ultrastructural changes in the medullary canal of the adult male New Zealand white rabbit associated with the trauma of the insertion of an inactive cathode were compared to that associated with electrically induced osteogenesis from an active cathode delivering 20 μA constant direct current. In the vicinity of both an inactive and an active cathode, the medullary canal cellular content was replaced first by polymorphic cells and later by osteoblastic new bone formation. The polymorphic cells always appeared in the immediate vicinity of a capillary or other blood vessel. With time, the new bone formation in the medullary canal surrounding the inactive cathode disappeared, while new formation surrounding the active cathode progressively increased in amount. When the new bone formation in the medullary canal surrounding an inactive cathode disappeared, it was replaced by a network of polymorphic cells. When direct current was then applied to such an inactive electrode, the polymorphic cells were again rapidly replaced by bone. The close association of polymorphic cells with osteoblasts suggests that the former may be a precursor cell of the latter.
Mechanical factors in electrode‐induced osteogenesis
Authors: Spadaro J. A. , Mino D. E. , Chase S. E. , Werner F. W. , Murray D. G. 
Published: February 2005

AbstractPrevious experiments have suggested that mechanical activity of electrode implants may contribute to the observed bone formation that has been attributed to the electrical currents. This was tested by implanting movable and stationary wires in the medullary canal of the rabbit femora or tibiae. The moving implants uniformly showed significant medullary bone formation at the wire, whereas the stationary ones did not. This bone persisted for as long as 8 weeks and was mostly resorbed by 12 weeks as the implants became fixed. The new trabecular bone closely resembled that typically seen at electrically active implants. Implant motion may have a more important role in electrically induced osteogenesis than previously thought.
In vivo versus in vitro polymerization of acrylic bone cement: Effect on material properties
Authors: Bargar W. L. , Brown S. A. , Paul H. A. , Voegli T. , Hseih Y. , Sharkey N. 
Published: February 2005

AbstractFlexural strength and molecular weight of polymethylmethacrylate bone cement were determined for cement polymerized in vivo in a canine total hip replacement and cement from the same batch polymerized in vitro. Both in vivo and in vitro samples showed a slight increase in flexural strength and modulus at 2 weeks, followed by a nearly equivalent decline at 8 weeks. In vitro and in vivo samples exhibit a comparable stress to failure, but the in vivo samples show a significantly increased strain and decreased modulus. Cement from the proximal region of the prosthesis has significantly decreased flexural strength, lower modulus, and lower molecular weight than cement from the distal region and plug, suggesting that failures in the proximal region of a prosthesis may be due to inferior physical and mechanical properties of the bone cement in that region.
Tensile properties of the medial collateral ligament as a function of age
Authors: Woo Savio L‐Y. , Orlando Carlo A. , Gomez Mark A. , Frank Cyril B. , Akeson Wayne H. 
Published: February 2005

AbstractThe biomechanical properties of the rabbit medial collateral ligament (MCL) as a function of maturation and age were investigated. Femur–MCL–tibia (F‐M‐T) preparations were obtained from rabbits of different age groups (open or closed epiphysis). Parallel increases in the animal body weight and ligament cross‐sectional area were recorded with age. Cyclic and tensile failure tests were performed to obtain the structural properties of the F‐M‐T complex and the mechanical properties of the MCL substance. There were significant increases in the load at failure, energy‐absorbing capability of the bone–ligament junction, and in the tensile strength of the ligament substance as a result of maturation and subsequent aging. Increases in the area of hysteresis obtained during cyclic loading–unloading were also documented. At the closing of the epiphysis, the mode of failure of the F‐M‐T structure progressed from tibial avulsion to failure in the midsubstance of the ligament. An asynchronous rate of maturation was observed between the structural properties of the bone–ligament complex and the mechanical properties of the ligament substance.
Tibial epiphyseal development: A cross‐sectional histologic and histomorphometric study in the New Zealand white rabbit
Authors: Masoud Ibrahim , Shapiro Frederic , Moses Alan 
Published: February 2005

AbstractSequential histomorphometric studies on the developing rabbit tibia from birth to skeletal maturity demonstrate that growth plate height lessens as longitudinal growth diminishes. Differing rates of development proximally and distally are documented. Distally, growth plate height, width, and area and total epiphyseal area peak or reach near maximum values by 3 weeks, whereas proximally, they do so by 8 weeks (except for height, which also peaks at 3 weeks). The distal growth plate is being obliterated by 16 weeks, at which time the proximal growth plate remains well structured and open. The distal tibia and fibula develop as one tissue mass. The articular cartilage and epiphyseal cartilage are continuous from birth, whereas a single ossification center and a single growth plate are present by 8 weeks. The data point to the presence of intrinsic growth plate, as well as systemic, control mechanisms affecting skeletal growth. Knowledge of temporal and quantitative features of epiphyseal and growth plate development will greatly aid in the elucidation of the underlying controls.
Biochemistry and antigenicity of osteoarthritic and rheumatoid cartilage
Authors: Schurman David J. , Palathumpat Marykutty V. , Desilva Anil , Kajiyama Glen , Smith R. Lane 
Published: February 2005

AbstractThe purpose of this study was to test whether cartilage serves as the source or repository of antigenic components active in the stimulation of inflammation in rheumatoid arthritis through an analysis of peripheral blood lymphocyte proliferation. Articular cartilage samples were obtained from patients with osteoarthritis, rheumatoid arthritis, and ankylosing spondylitis undergoing joint replacement surgery. Each sample was homogenized and characterized biochemically with respect to the content of proteoglycan, collagen, and immunoglobulin. Proteoglycan content of rheumatoid cartilage was reduced by 71% when compared to osteoarthritic cartilage; the proteoglycan content of ankylosing spondylitis cartilage was reduced by 40% when compared to osteoarthritic cartilage. Immunoglobulins were detectable in all cartilage samples when analyzed by ELISA or endoplate titration. Lymphocyte proliferation, quantified by uptake of 3H‐thymidine, was unaltered by addition of cartilage fragments, low (saline) and high salt extracts (2.0 M CaCl2), or cartilage residues. Both autologous and heterologous lymphocytes were tested against the cartilage samples with no difference in reactivity. Purified bovine articular proteoglycans and Type II collagen were also inactive. Although tetanus toxoid and phytohemaglutinin were effective stimulants of proliferation, lymphocytes from arthritis patients were suppressed relative to those of normal individuals. Analysis of arthritic articular cartilage by these techniques failed to demonstrate the presence of antigen(s) stimulating proliferation of peripheral blood lymphocytes.
Age‐related changes in the kinetics of release of proteoglycans from normal rabbit cartilage explants
Authors: Sandy John D. , Plaas Anna H. K. 
Published: February 2005

AbstractThe release of proteoglycans from explant cultures of articular cartilage from immature and mature rabbits has been studied with the following results. At both ages the tissue proteoglycan was released in two phases: an initial extensive release (day 0 to 3) and a period of slow release (day 4 to 15). The percentage released in the initial phase was, however, significantly greater for mature (55%) than immature (38%) explants. At both ages the newly synthesized proteoglycans (in vivo labeled) were also released in two kinetic pools. Thus, graphical analysis of release data readily resolved the disappearance curves into two linear components with in vitro half‐lives of 1 day and 22 days. Again, the percentage in the short half‐life pool was much greater for mature (70%) than immature (40%) explants. At both ages the initial release was largely chondrocyte‐mediated since freeze‐thawing the tissue before culture markedly reduced proteoglycan release. At both ages the released proteoglycans were smaller than equivalent preparations of extracted proteoglycans and they were much less capable of forming aggregates with hyaluronate. The results show that there are age‐dependent changes in rabbit articular cartilage that increase the proportion of proteoglycans, both total and newly synthesized, that are susceptible to rapid chondrocyte‐mediated catabolism in explant cultures.
Tensile properties of human knee joint cartilage: I. Influence of ionic conditions, weight bearing, and fibrillation on the tensile modulus
Authors: Akizuki Shaw , Mow Van C. , Müller Francisco , Pita Julio C. , Howell David S. , Manicourt Daniel H. 
Published: February 2005

AbstractThe flow‐independent (intrinsic) tensile modulus of the extracellular matrix of human knee joint cartilage has been measured for normal, fibrillated, and osteoarthritic (removed from total knee joint replacements) cartilage. The modulus was determined in our isometric tensile apparatus and measured at equilibrium. We found a linear equilibrium stress‐strain behavior up to ∼15% strain. The modulus was measured for tissues from the high and low weight‐bearing areas of the joint surfaces, the medial femoral condyle and lateral patello femoral groove, and from different zones (surface, subsurface, middle, and middle‐deep) within the tissue. For all specimens, the intrinsic tensile modulus was always less than 30 MPa. Tissues from low weight‐bearing areas (LWA) are stiffer than those from high weight‐bearing areas (HWA). The tensile modulus of the ECM correlates strongly with the collagen/proteoglycan ratio; it is higher for LWA than for HWA. Osteoarthritic cartilage from total knee replacement procedures has a tensile stiffness less than 2 MPa.
Fibronectin and water content of articular cartilage explants after partial depletion of proteoglycans
Authors: Burton‐Wurster Nancy , Lust George 
Published: February 2005

AbstractThe aim of this study was to test the hypothesis that fibronectin in cartilage of osteoarthritic joints accumulates in increased quantities in response to a reduction in proteoglycan content in the matrix. We determined fibronectin content in an ELISA system, uptake of plasma 125I‐fibronectin from the medium, and glycosaminoglycan content by a dye method. The proteoglycan content of canine articular cartilage was reduced by co‐incubation of the cartilage with canine synovium, partially purified catabolin, or retinoic acid. Data suggested that proteoglycan loss alone was not sufficient to result in the increased fibronectin accumulation that has been reported in the deteriorating articular cartilage of osteoarthritic joints. Cartilage that lost as much as 75% of its proteoglycan content did not have increased fibronectin content and did not take up more fibronectin from the external medium. A related goal of this study was to evaluate the percentage of water in proteoglycan‐depleted but disease‐free cartilage, as the percentage of water is known to be elevated in osteoarthritic cartilage. Data indicated that the percentage of water in the depleted cartilage increased in proportion to the decrease in proteoglycan content, but the total amount of water in the cartilage did not increase; water content appeared to be unchanged. Under the conditions used, the proteoglycan content was reduced and the percentage of water was elevated, but fibronectin content was not increased. Thus, the cartilage incubated in vitro did not mimic osteoarthritic cartilage.
Antibiotic stability in an implantable pump
Authors: Perry Clayton R. , Ellington Lisa L. , Becker Annette , Vossen Mark K. , Burdge Robert E. , Greenberg Richard N. 
Published: February 2005

AbstractWe measured the stability of vancomycin, amikacin, netilmicin, tobramycin, gentamicin, clindamycin, and aztreonam in an implantable drug pump. Two pumps were filled with the antibiotic being tested and were incubated at 37° for 3 weeks. Samples were taken daily. At 3 weeks the pumps were disassembled and examined microscopically for signs of deterioration. If the pumps were intact, bioassays were used to quantitate the biologic activity of each daily antibiotic sample. Vancomycin degraded the pump. Amikacin, netilmicin, tobramycin, gentamicin, clindamycin, and aztreonam had no effect on the pump and maintained their biologic activity over the 3‐week period.
A comparison of various types of fixation devices for protection of the posterior cruciate ligament against a posterior drawer force
Authors: O'Meara Clifton B. , Tencer Allan F. , Ivey Frank M. , Woodard Peggy 
Published: February 2005

AbstractWe compared four different fixation devices to determine which offers the greatest relative protection to the posterior cruciate ligament (PCL) against elongation with an applied posterior drawer force. We designed a system to monitor and record the change in distance between an approximate origin and insertion of the PCL as known forces were applied posteriorly to the tibia with the femur fixed. Six fresh cadaver knees were used in this investigative series. They were first tested with the PCL intact, then with the PCL transected, and then with the various fixation devices applied. After comparing the results with transarticular pins and quadrilateral and anterior half‐frame external fixators, we found that transarticular fixation offers significantly greater protection to the PCL. This study may prove to be helpful to the orthopaedist when selecting ancillary fixation for posterior cruciate repair or reconstruction.
Load‐displacement behavior of sacroiliac joints
Authors: Miller J. A. A. , Schultz A. B. , Andersson G. B. J. 
Published: February 2005

AbstractWe measured the load‐displacement behavior of both single and paired sacroiliac (SI) joints in fresh cadaver specimens obtained from eight adults between the ages of 59 and 74 years. With both ilia fixed, static test loads were applied to the center of the sacrum along and about axes parallel and normal to the superior S1 endplate. Test forces up to 294 N were applied in the superior, inferior, anterior, posterior, and lateral directions. Moments up to 42 N‐m were applied in flexion, extension, lateral bending, and axial torsion. Displacement of the center of the sacrum were measured 60 s after each load increment was applied, using dial gauges and an optical lever system. The tests were then repeated with only one ilium fixed. Finally, the three‐dimensional location and overall geometry of each SI joint were measured. For an isolated left joint at the maximum test loads, the mean (SD) sacral displacements in the direction of the force ranged from 0.76 mm (1.41) in the medial to 2.74 mm (1.07) in the anterior direction. The mean rotations in the direction of the moments ranged from 1.40° (0.71) in right lateral bending to 6.21° (3.29) in clockwise axial torsion viewed from above. We also examined load‐displacement behavior under larger loads. Single sacroiliac joints resisted loads from 500 to 1440 N, and from 42 to 160 N‐m without over failure.
Porous hydroxyapatite as a bone graft substitute in diaphyseal defects: A histometric study
Authors: Holmes Ralph E. , Bucholz Robert W. , Mooney Vert 
Published: February 2005

AbstractPorous hydroxyapatite (IP200), formed by conversion of the Poritidae porites exoskeleton, has pores averaging 230 μm and pore interconnections averaging 190 μm in diameter. In the distal radial diaphyses of 14 dogs, bilateral 7.5 × 20mm cortical windows were created and fitted with 5 × 7.5 × 20 mm blocks of IP200 implants and liiac autograft. Both implanted and contralateral grafted radius specimens were retrieved at 3, 6, 12, 24, and 48 months. Unstained undecalcified sections were examined by microradiography and UV epi‐illumination. Stained undecalcified sections were examined by light microscopy and quantitated by histometric methods. Implant specimens demonstrated good union and bone ingrowth at all time intervals. The implant specimens were composed of (mean ± SE) 10.6% ± 1.0% soft tissue, 51.2% ± 1.3% bone, and 38.2% ± 1.0% IP200. The graft specimens showed good union with little apparent ingrowth at 3 months, followed by progressive appositional closure of cancellous spaces. The graft specimens contained 21.9% ± 0.9% bone at 3 months with increases at each time interval to 73.1% ± 8.7% at 48 months. The volume fraction and mean width of IP200 did not change with time, confirming the absence of implant biodegradation. The volume fraction and mean width of bone remained stable in the implant but increased in the graft specimens, corresponding to graft neocortex formation. It is concluded that implants initially filled in with bone while grafts initially replaced much of their spongiosa and subsequently filled in with bone. Histometry of untreated defects and measurement of mechanical properties are suggested for further study.