bluuebunny/crossref_metadata_2025_split huggingface dataset:
Telemeterized in vivo hip joint force data: A report on two patients after total hip surgery
Authors: Kotzar G. M. , Davy D. T. , Goldberg V. M. , Heiple K. G. , Berilla J. , Heiple K. G. , Brown R. H. , Burstein A. H. 
Published: February 2005

AbstractTwo telemeterized femoral components were implanted in two patients as part of normal total hip replacement procedures. The two components were instrumented to measure the three force components directed along: (a) the neck axis, (b) transverse to the neck axis and in the plane of the prosthesis, and (c) transverse to the neck axis and perpendicular to the plane of the prosthesis. Data were collected at multiple sessions during the early postoperative period for a number of standard activities, including gait, stair climbing, rising from a chair, single leg stance, double leg stance, ipsilateral and contralateral straight leg lifts while supine, ipsilateral flexion and extension while standing, and ipsilateral abduction while standing and lying on the contralateral side. These data are summarized and compared with the published results from analytic studies and with the results from previous studies using instrumented femoral components. Peak loads for gait during the period of study were roughly 2.7 body weights (BW) when the patients walked at their normal pace. Contact forces at the hip during stationary single leg stance approximated the peak loads during gait with values ranging from 2.1 to 2.8 BW. The highest forces recorded reached values approaching 5.5 BW and occurred during periods of instability while the patient engaged in stationary single leg stance. Our in vivo data indicate that forces generated during the above activities increase in magnitude quite rapidly during the early postoperative period and that during this period the patients have the ability to perform the activities of daily living without generating the high amplitude joint contact forces suggested by the results of dynamic studies. Joint contact forces during gait were found to depend on speed, but the high absolute magnitudes predicted by model studies were not supported by the in vivo data.
Evaluation of orthogonal mechanical properties and density of human trabecular bone from the major metaphyseal regions with materials testing and computed tomography
Authors: Ciarelli M. J. , Goldstein S. A. , Kuhn J. L. , Cody D. D. , Brown M. B. 
Published: February 2005

AbstractWe evaluated the orthogonal mechanical properties of human trabecular bone from the major metaphyseal regions with materials testing and quantitative computed tomography (CT). The proximal tibia, distal femur, proximal femur, distal radius, and proximal humerus from fresh cadaver specimens between the ages of 55 and 70 years were excised and prepared for experimentation. The bones were embedded and scanned at 1 or 1.5 mm intervals on a Technicare HPS 1440 and GE 9800 CT scanner. After scanning, the bones were sectioned, producing 8‐mm cubes of trabecular bone which were mechanically tested in uniaxial compression at a strain rate of 1%/s. The testing sequence consisted of preyield tests in two of the three orthogonal directions and failure in the third. After testing, the cubes were evaluated for apparent density and ash weight. The results of the study show that the strength and stiffness of trabecular bone varies significantly within metaphyseal regions and from metaphysis to metaphysis. The power and significance of relationships between density and modulus varied as a function of metaphyseal location. Both linear and nonlinear models were significant, suggesting that trabecular deformation occurs in response to both axial and bending loads. Finally, the need for architectural measures of trabecular bone to predict mechanical properties is emphasized.
Electrokinetic behavior of intact wet bone: Compartmental model
Authors: Walsh W. R. , Guzelsu N. 
Published: February 2005

AbstractStreaming potential experiments were performed on chemically‐treated intact wet bone plugs equilibrated in potential‐determining ion buffers. Comparison of calculated zeta (ζ) potentials from intact wet bone streaming potentials and bone particle electrophoresis indicates different values. Intact streaming potential experiments, where fluid is forced through the samples, represents flow, primarily through the vascular channel system, and contribution of the organically‐lined channels to the electrokinetic (ζ) potential. Bone particle electrophoresis represents mainly the electrokinetic contribution of exposed mineralized matrix. The organic linings present in the vascular chanel system limit potential‐determining ions' access to the mineralized matrix. These linings may have an important role in mineral homeostasis and control of ion fluxes between bone compartments.
Human carpal ligament recruitment and three‐dimensional carpal motion
Authors: Savelberg H. H. C. M. , Kooloos J. G. M. , De Lange A. , Huiskes R. , Kauer J. M. G. 
Published: February 2005

AbstractIn five fresh human cadaver wrist joints six carpal ligaments and seven carpal bones were marked with small, radio‐opaque pellets. Using a roentgenstereophotogrammetric measuring system, the ligamentous length changes and the kinematics of carpal bones were determined in different flexion and deviation positions of the hand. The data generated by this method differ significantly from lengthening data predicted by current concepts on carpal ligament functioning. The motions of carpal bones and the lengthening of the carpal ligaments were related to each other. It appeared that most carpal ligaments lengthen only during one half of a full movement cycle. Hence, ligaments seem to constrain either a dorsal‐ or a palmar‐directed motion of the hand, or an ulnar‐ or a radial‐directed motion of the hand. When the hand is in maximal radial deviation or maximal palmar flexion, none of the ligaments has a greater length than in the neutral situation. The tested parts of the lunatotriquetrum palmar ligament do not lengthen during any movement of the hand. Significant lengthening relative to the neutral situation was found for the radiocapitate palmar ligament (6.5% in maximal ulnar deviation and 11.7% in maximal dorsal flexion of the hand), and for the distal string of the radiolunate palmar ligament (6.4% in maximal ulnar deviation). It was confirmed that the carpals, apart from moving in the plane in which the hand motion takes place, also execute considerable out‐of‐plane motions during hand motions. The combination of these expermentally and simultaneously determined data on length change and on the movements of carpal bones are found to be necessary in order to give suitable explanations for the observed separate kinematical phenomena.
Ascorbic acid requirement for optimal flexor tendon repair in vitro
Authors: Russell Jean E. , Manske Paul R. 
Published: February 2005

AbstractNumerous studies from our laboratory have defined aspects of the repair process in a lacerated flexor tendon model, both in vivo and in vitro. Inherent in the development of a viable tissue or cell culture model system is the definition of the optimal media environment. Since our laboratory investigations of in vitro flexor tendon repair encompass the formation of numerous extracellular matrix proteins, we have defined the optimal level of ascorbic acid with which to study the tendon wound healing process. The ascorbic acid requirement for proline and lysine hydroxylase activity during collagen biosynthesis is well known, and the importance of this vitamin for matrix proteoglycan synthesis more recently has been appreciated. This report describes the effect of several levels of ascorbic acid on 3H‐thymidine incorporation, collagen and noncollagen protein synthesis, and glucose utilization and lactate production. Profundus flexor tendon segments were obtained from young adult New Zealand white rabbits and maintained in organ culture for periods of 1, 2, or 3 weeks. Ascorbic acid concentrations ranged from 50 to 300 μg/ml and were added fresh at each 48‐h media change. Tendon protein synthesis, glucose metabolism, and cell permeability/viability were significantly correlated with the level of ascorbic acid in the culture medium. The results suggest that ascorbic acid levels in excess of the traditional 50 μg/ml are necessary to optimally maintain flexor tendons from adult animals in organ culture with 48‐h media and ascorbate changes. Additionally, it may be necessary to determine the precise ascorbic acid requirement for individual tissues, since the specific tissue/cell and species requirement for ascorbate may vary.
Alterations in femoral and acetabular bone strains immediately following cementless total hip arthroplasty: An in vitro canine study
Authors: Page Alexandra , Jasty Murali , Bragdon Charles , Ito Keita , Harris William H. 
Published: February 2005

AbstractAlterations in strain patterns in both the femur and acetabulum of the dog, due to cementless total hip arthroplasty (THA), were evaluated by monitoring cortical bone strains before and immediately following implantation of components, using an accurate in vitro jig, simulating the loading of the canine hip in vivo. Femoral arthroplasty with straight stem, canal‐filling, femoral components, made of titanium‐based alloy, led to a statistically significant reduction of proximal femoral bone strains, with proximal medical compressive strains reduced, on average, to only 22% of intact strain magnitude (p < 0.01), even though the prostheses contained collars and were not fixed with cement. Strain alterations on the acetabulum, following cementless THA, were more complex and variable. Laterally, a significant decrease (p < 0.01) in periacetabular strains to between 20 and 60% of the intact state was observed, while medial wall strains varied inconsistently after arthroplasty. These strain alterations reflect major changes in mechanical loading of both the femur and acetabulum immediately following cementless THA, using components similar to those used clinically in humans. Major reductions in strains on the proximal femur occurred with cementless femoral components, while the change in strains on the acetabulum were variable, and could be a result of variations in fit and placement of components inherent even in well‐controlled implantation techniques. The physiologic in vitro loading of the canine femur with the pelvis, used to obtain these data, can be applied to future investigations exploring stress transfer around uncemented components and the relationship of stress transfer to morphological changes of bone, in the canine model.
Evidence of proteoglycan/proteoglycan interactions within aggregates
Authors: Kahn Anthony , Pottenger Lawrence A. , Phillips Frank M. , Viola Randall W. 
Published: February 2005

AbstractNonaggregated proteoglycan monomers, digested fragments of the monomers, as well as link proteins have been shown to self‐associate. These associations have not been shown to occur on the aggregate. However, previous reports, using the Kleinschmidt technique of monolayer electron microscopy, have noted proteoglycan subunits on the aggregate that appear to interact, either as branched proteoglycans or as proteoglycan subunits that appear to share the same attachment site on the hyaluronic acid chain. Branching and shared attachments were noted in all aggregates analyzed in this study. Increasing the average space between proteoglycan subunits on the reconstituted aggregated resulted in a significant decrease in branched proteoglycans, indicating either a weak association occurring on the aggregate, or an artifact created by a three‐dimensional structure being reduced to a two‐dimensional monolayer image. The shared attachments were independent of both the presence of link proteins and changes in spacing between proteoglycans, suggesting a proteoglycan—proteoglycan interaction occurring before aggregation. The interactions were not influenced by proteoglycan concentration at the time of aggregation. Link proteins, however, did increase the number of proteoglycans on the aggregate that could be cross‐linked with a bifunctional reagent, suggesting that link proteins facilitate proteoglycan—proteoglycan interactions.
Vascular assessment of the periarticular ligaments of the rabbit knee
Authors: Wallace C. Douglas , Amiel David 
Published: February 2005

AbstractWhile the rabbit is being extensively utilized in animal models for orthopaedic research, the vascular anatomy of the knee ligaments has not been thoroughly described in this species. This study demonstrates the blood supply to the infrapatellar fat pad, the cruciate ligaments, the medial collateral ligament (MCL), and the menisci, such that the effects of manipulating these tissue may be properly interpreted. Vascular injection with India ink and iodinated i.v. contrast dye was performed in 11 New Zealand white rabbits, and routine histology done on six. The large vessel anatomy is similar to that described for humans and dogs, with a descending geniculate artery, medial and lateral superior and inferior geniculate arteries, a posterior geniculate artery, and a recurrent anterior tibial artery. The microvascular anatomy is also similar in that the infrapatellar fat pad and synovial membrane are highly vascular, the menisci are vascularized from their periphery (being avascular centrally), and the medial collateral ligament is relatively well vascularized. A difference from dogs and humans is present in the anterior cruciate ligament (ACL), which is poorly vascularized, with a single artery on its anterior aspect. High magnification histologic evaluation reveals numerous capillaries in the substance of the MCL, while the ACL is nearly devoid of such vessels. The interspecies variation in vascular anatomy is a variable that must be taken into consideration in any surgical or traumatic animal model investigation of knee pathology.
Remodelling of bone around intramedullary stems in growing patients
Authors: Blunn Gordon W. , Wait Mary E. 
Published: February 2005

AbstractThe remodelling of bone around intramedullary cemented stems, used for the fixation of massive distal femoral replacements in young patients, has been studied. Several types of remodelling have been identif ed, and this is common to all of the retrieved specimens that have been in situ for periods of 6 to 18 months. Transection of cortical bone and the insertion of a massive prosthesis leads to (a) the formation of a pedicle of bone or bony bridge that grows from the transection site over the shaft of the prosthesis, (b) bone resorption at the transection site, (c) the development of an inner porotic cortex surrounding the intramedullary stem and subperiosteal bone formation, and (d) a shell of bone around the acrylic cement. The tibial component that allows continued growth of the proximal tibial physis consists of a press fit metallic plateau with a stem that slides into an ultra‐high‐molecular‐weight polyethylene sleeve inserted below the growth plate. A sclerotic layer of bone forms adjacent to a soft‐tissue interface around both the sleeve and the metallic component. Remodelling of bone around intramedullary stems is attributed either to a redeveloping blood supply or to load adaptive changes.
Changes in tibial bone mass after primary cementless and revision cementless total hip arthroplasty in canine models
Authors: Goethgen C. B. , Sumner D. R. , Platz C. , Turner T. M. , Galante J. O. 
Published: February 2005

AbstractThe purpose of this study was to examine right—left differences in tibial bone mass after unilateral (left) cementless total hip arthroplasty (THA). Of 39 dogs with THAs, 9 had primary cementless porous‐coated femoral stems for 6 months and 15 had similar stems for 2 years. Five dogs had aseptically failed cemented hips, and 10 had aseptically failed cemented hips that were revised with cementless porous‐coated femoral stems (5 without bone graft and 5 with autogenous bone graft). These animals were sacrificed 6 months after the revision surgery. The primary cementless dogs showed no right‐left difference in tibial bone mineral content (BMC) or cortical bone cross‐sectional geometry after 6 months, but after 2 years there was a distal right‐left difference in BMC of 6% caused by expansion of the medullary canal in the tibia of the operated limb. Tibial BMC was more than 20% lower in the operated limb of the failed cemented dogs, approximately 15% lower in the nongrafted group, and 7% lower in the grafted group. The right‐left tibial difference in BMC in the 2‐year primary cementless group is most probably because of subclinical disuse of the operated limb. Among the dogs with failed cemented stems, the lower right‐left difference in the two revised groups compared with the nonrevised group suggests that improved limb function after cementless revision THA may cause gain of previously lost bone.
In vivo flexion/extension of the normal cervical spine
Authors: Dvorak J. , Panjabi M. M. , Novotny J. E. , Antinnes J. A. 
Published: February 2005

AbstractTwenty‐two women (age range 25—49 years, average 30.9 years) and twenty‐two men (age range 23—42 years, average 31.6 years), all healthy and asymptomatic, underwent passive flexion/extension examinations of the cervical spine. Functional x‐rays were taken and analyzed using a computer‐assisted method that quantified intervertebral rotations, translations, and locations of the centers of rotation for each level C1‐C2—C6‐C7. The aim of the study was to establish values for these parameters for a normal population as related to age and gender. In the process, a statistically significant difference was found in the average value of rotation between male and female groups at the C5‐C6 level. A new parameter, the ratio between translation and rotation, was also established and may prove useful for clinical diagnoses. This parameter has a smaller error associated with it than do pure translations and may aid the clinician by helping to account for the large variation in rotatory ranges of motion within the population. This translation/rotation ratio indicated highly significant differences in the lower segments of the cervical spine between gender groups.
Effects of indomethacin on demineralized bone‐induced heterotopic ossification in the rat
Authors: DiCesare Paul E. , Nimni Marcel E. , Peng Lynnus , Yazdi Mohamadreza , Cheung David T. 
Published: February 2005

AbstractIndomethacin inhibits bone formation when treatment is initiated before the implantation of demineralized bone matrix (DBM). For the inhibition of bone induction to occur, indomethacin treatment had to be initiated 6 h or more before implantation of DBM. Initiating the drug treatment at or after the time of DBM implantation had no effects on the amounts of new bone formed. The inhibition by indomethacin is dose related over a range between 0.04 and 4 mg/kg body weight. Recovered day‐1 DBM implants, transplanted into indomethacin pre‐ and posttreated syngeneic rats, formed bone at the same rate as controls did. However, recovered day‐1 DBM implants lyophilized before transplantation showed decreased bone formation but significant dystrophic calcification as judged by a lower alkaline phosphatase activity and an elevated calcium content.
Regional blood flow and strontium‐85 incorporation rate in the rat hindlimb skeleton
Authors: Kirkeby Ole J. , Berg‐Larsen Trine 
Published: February 2005

AbstractRegional distribution of radioactive microspheres and 85Sr incorporation rate in the os ilium, femur, and tibia were determined in 44 rats. In 15 additional animals, regional blood flow was measured with the reference sample technique. Highest numbers of microspheres were found in the distal femoral and proximal tibial metaphyses. Highest blood flow rates were found in the os ilium, the caput femoris, and distal femoral and proximal tibial metaphyses. The diaphyses and epiphyses of the femur and tibia had a relatively lower perfusion. The regional 85Sr incorporation rate was correlated (r = 0.67) to the regional distribution of the microspheres. The dispersion of the data was large and this was mainly due to biological variation. The results describe the regional distribution of blood flow in the rat hindlimb and demonstrate a close association between blood flow and mineral turnover in normal rat skeletal tissue as shown by the correlation between microsphere and 85Sr incorporation rate distribution.
Determination of fixed charge density in cartilage using nuclear magnetic resonance
Authors: Lesperance Leann M. , Gray Martha L. , Burstein Deborah 
Published: February 2005

AbstractMany biomechanical and chemical properties of cartilage are dependent on the fixed charge density (FCD) of the extracellular matrix. In this study, nuclear magnetic resonance (NMR) spectroscopy was investigated as a nondestructive technique for determining FCD in cartilage. Sodium content was measured by NMR in cartilage explants and was compared with sodium content measured by inductively coupled plasma emission spectroscopy (ICP) in order to verify the total NMR visibility of sodium in cartilage. The ratio of NMR to ICP results was 1.02 ± 0.04 (calf, mean ± SD, n = 7) and 1.04 ± 0.11 (adult bovine, n = 8). Sodium concentration as measured by NMR was then used with ideal Donnan theory to compute estimates of FCD. For calf articular cartilage (AC) near physiological conditions, calculated FCD was −0.28 ± 0.03 M (n = 10). NMR measurements were then made for individual cartilage specimens sequentially equilibrated in baths of differing salt composition, pH, or ionic strength. For calf and adult AC, calculated FCD decreased dramatically between pH 3 and 2, with adult speciments becoming positively charged but calf tissue retaining a net negative charge. For calf AC equilibrated in 0.3–0.015 M NaCl, calculated FCD was observed to decrease slightly with decreasing bath ionic strength. For epiphyseal cartilage, FCD varied with the position of origin of the explant within the joint, ranging from − 0.19 to − 0.35 M in a manner that correlated with tissue glycosaminoglycan content. Preliminary NMR imaging experiments demonstrated similar variations of sodium concentration in intact ulnar epiphyseal cartilage. Collectively, these results demonstrate the ability of NMR to nondestructively follow FCD in cartilage. The technique is applicable to dynamic studies as well as to both in vitro and in vivo studies on living tissue.
Effect of hylan on cartilage and chondrocyte cultures
Authors: Larsen Nancy E. , Lombard Kathleen M. , Parent Edward G. , Balazs Endre A. 
Published: February 2005

AbstractThe protective role of hylan, a hyaluronan [hyaluronic acid (HA)] derivative, was studied in explanted bovine cartilage and isolated chondrocytes. Cartilage and chondrocytes were exposed to degradative enzymes (lysate from activated polymorphonuclear leukocytes), oxygen‐derived free radicals (ODFR), conditioned media from mononuclear cells (MCCM), and interleukin‐1 (IL‐1), in the presence and absence of hylan. The effect of HA was also studied. In cartilage explants susceptibility to pertubation was evaluated in terms of 35S release and proteoglycan depletion and was compared to control cultures; high viscosity hylan was found to reduce 35S release in cartilage explants caused by degradative enzymes, ODFR, MCCM, and IL‐1. The hylan effect was reversible and viscosity‐dependent. In chondrocyte cultures, high viscosity hylan was effective in reducing cell injury caused by degradative enzymes and ODFR. The data suggest that the glycosaminoglycan hylan, as well as native HA, may mediate exposure to and/or response to stimuli associated with initiation of degenerative processes in cartilage tissues.